Abstracts from the 2021 AMSA Reciprocal Meat Conference

1 ALTERNATIVE MERCHANDISING STRATEGY OF THE BEEF TOP ROUND

B. Epperson^1*, J. Van Buren¹, J. Nasados¹, J.Lancaster¹, P. Bass¹, K. Smith¹, M. Colle¹, K. Puga¹, B. Buseman¹, and K. Insausti Barrenetxea², ¹Animal, Veterinary, and Food Science, University of Idaho, Moscow, Idaho, USA; ²Agricultural Engineering School-IS Food, Public University of Navarra, Pamplona, Spain, *eppe6047@vandals.uidaho.edu

Objectives: Whole top rounds can lack color uniformity, causing discounts at the retail counter and profit loss due to color having a large influence on consumers’ willingness to purchase. The primary objective of this study was to compare the deep portion, superficial portion, and whole beef top round steaks (semimembranosus [SM] muscle) for consumer willingness to purchase based upon visual appraisal of steak pictures.

Materials and Methods: USDA Choice top rounds (Institutional Meat Purchase Specifications 168; n = 12) were purchased from a commercial food distributer and aged from 21 to 24 d from their pack date before the removal of the SM. Five steaks were cut from each SM proximally to distally and systematically assigned to 0, 1, 2, 3, or 4 d of retail display. Steaks were displayed in a glass-fronted retail display case at 3°C. On the assigned day of retail display, whole steaks were pictured 15 inches above the steak. This was then followed by separation of the deep/superficial portions approximately 5 cm from the steak’s superficial edge. Individual pictures of the deep and superficial portions were then taken as described earlier. The survey was distributed online though Qualtrics. Pictures were randomized, and each participant evaluated 18 images. After evaluating each picture, participants were asked whether they would purchase the steak. If yes, they were asked how much they would be willing to pay per pound ($2.58, $3.58, $4.58, $5.58, or >$6.58). If no, they were asked why not, with options including the amount of trim, toughness, color, and amount of marbling. Data were analyzed using the glimmix procedure of SAS (SAS Institute Inc., Cary, NC).

Results: Significance was determined at P < 0.05. A total of 265 consumers completed the survey, and 3,507 purchase decisions were made. For willingness to purchase, there was not an interaction (P = 0.1761) between day of retail display and steak portion. However, there was a difference (P < 0.001) between steak portions. Consumers preferred the superficial portion over the whole steak and the whole steak over the deep portion. There was also a difference (P < 0.001) between days of retail display. Interestingly, in general, consumers preferred steaks on days 1, 2, and 3 over steaks on days 0 and 4 of retail display.

Conclusion: In conclusion, consumers were more willing to purchase the superficial portion of the SM over the whole steak. This could allow for an alternative merchandising strategy of the top round, which potentially would add value to the beef round.

Keywords: alternative fabrication, consumer survey, top round

2 NUTRIENT PROFILE COMPARISON OF PLANT-BASED MEAT ALTERNATIVES AND GROUND PORK

C. J. Swing ¹, M. J. Hernandez ^1*, T. W. Thompson ¹, O. B. Guimaraes ¹, I. Geornaras ¹, T. E. Engle ¹, K. E. Belk ¹, C. L. Gifford ², and M. N. Nair ¹, ¹Animal Science, Colorado State University, Fort Collins, Colorado, USA; ²Animal Science, University of Wyoming, Laramie, Wyoming, USA, *michaelj.hernandez@colostate.edu

Objectives: Animal-based meat products are an important source of nutrients in human diets; however, plant-based meat alternatives (PBMA) have been gaining popularity in recent years, and it could be an important source of nutrients for some consumers. However, a substantial knowledge gap exists about the full nutrient profile of PBMA and animal-based meat products. Therefore, the nutrient profiles of original and current formulations of popular PBMA, such as the Beyond Meat Burger (BMB1 and BMB2), the Impossible Food Burger (IFB1 and IFB2), and Morning Star’s Black Bean Burger, were assessed in comparison with 80/20 ground pork (GP) for proximate, mineral, vitamin, fatty acid, and amino acid profiles.

Materials and Methods: The BMB1, BMB2, IFB1, IFB2, Black Bean Burger, and GP products were purchased at foodservice companies and supermarkets from 6 randomly selected cities throughout the United States. Six replicates (n = 6) of each food product (i.e., one replicated per city) were formed into 113-g patties and either left raw or cooked on preheated aluminum skillets to an internal temperature of 71°C. Both raw and cooked products were frozen in liquid nitrogen and immediately homogenized until a uniform powder was obtained. Homogenized samples of raw and cooked products were then analyzed for proximate, mineral, vitamin, fatty acid, and amino acid profiles according to official procedures put forth by the AOAC. Simple means and standard deviations of each nutrient in each product were calculated, and statistical differences were determined at an alpha level of 0.05 using an analysis of variance with Tukey adjusted P values.

Results: Crude protein and fat content did not differ (P > 0.05) between the PBMA and GP after cooking. Sodium, calcium, and iron content were considerably greater (P < 0.05) in all PBMA than GP. Magnesium content in BMB2 and IFB2 were also greater (P < 0.05) than in GP, as was Vitamin E content in all PBMA, when compared with GP. IFB1 and IFB2 products were either numerically comparable to or statistically greater than (P < 0.05) GP in each B vitamin assessed, except pantothenic acid (B₅), for which GP was greater (P < 0.05). Total saturated and monounsaturated fatty acid content was numerically greater in BMB2 and IFB2 than GP. Total essential amino acid content was numerically greater in BMB2 than in GP, although anabolically important essential amino acids, such as methionine and lysine, were substantially greater (P < 0.05) in GP than in all the PBMA evaluated.

Conclusion: High sodium and saturated fatty acid content in PBMA may be a health concern for some consumers. The high concentrations of calcium, magnesium, and thiamin (B₁) and the presence of other nutrients found in PBMA could have implications for bioavailability. Therefore, the integration of dietary nutrients into the food matrix of PBMA and bioavailability of nutrients should be further investigated.

Keywords: plant-based meat alternatives, animal-based meats, amino acid profile, fatty acid profile

3 CHANGES IN THE PERCEPTION OF GROUND BEEF QUALITY AS A RESULT OF PRICE PER POUND LABELING

E. S. Beyer^1*, K. M. Harr¹, S. G. Davis¹, K. J. Farmer¹, M. D. Chao¹, J. L. Vipham¹, M. R. Zumbaugh¹, and T. G. O’Quinn¹, ¹Animal Sciences and Industry, Kansas State University, Manhattan, Kansas, USA, *erbeyer@ksu.edu

Objectives: The objective of this study was to determine the effect of perceived palatability on ground beef patties by providing consumers with differing price per pound labels.

Materials and Methods: Ground beef chubs (n = 15) of 80% lean, 20% fat composition were procured from a beef processor from the same lot. Patties were formed 11 d after processing into 151.2 g patties using a commercial patty former. Every 2 patties were packaged together with a 4-digit identification code with one of the following price labels: Ultra-High, High, Medium, Low, Ultra-Low and no information (NONE). For all panels, samples were thawed 24 h in advance, cooked to an endpoint temperature of 71°C on Cuisinart Clamshell Grill. The consumers (n = 105) were asked to evaluate each sample independently with the following information provided prior to sampling: $13.78/kg Ultra-High; $11.02/kg High; $8.27/kg Medium; $5.51/kg Low; $2.75/kg Ultra-Low or no information provided. Each round, all consumers were given the same information about the price per pound for each sample. The consumers were asked to evaluate each sample for tenderness, juiciness, texture liking, flavor liking, and overall liking. Additionally, the consumers were asked to list whether the sample was acceptable for all traits. The consumers reported their likelihood to purchase each sample. Data were analyzed using SAS Proc GLIMMIX as a completely randomized design.

Results: There were no differences (P > 0.05) among any of the various price labels for tenderness, texture liking, and overall liking. Consumers were equally as likely (P > 0.05) to purchase all samples regardless of the price label. However, the consumers listed price as one of the top purchasing motivators, similar (P > 0.05) to fat content and appearance. Consumers found the Ultra-High, Medium, and Ultra-Low price label to be more juicy (P < 0.05) than the Low price or NONE label. Also, consumers gave a higher (P < 0.05) flavor liking score to the Ultra-High, High, Medium, and Ultra-Low price labels in comparison with the NONE label. The Ultra-High and Medium price labels had a greater (P < 0.05) change in ratings for overall liking than the Ultra-low and Low price labels when compared with the NONE label. Furthermore, almost every price label for every trait resulted in increased (P < 0.05) palatability ratings, aside from the Low price label for juiciness, tenderness, and overall liking. A greater (P < 0.05) percentage of samples with the Ultra-High and Medium price level were rated as acceptable for juiciness in comparison with the low price and NONE label. A greater (P < 0.05) percentage of samples labeled with the Ultra-High and Medium price labels were considered acceptable for flavor in comparison with all other price labels. Lastly, a greater (P < 0.05) percentage of samples labeled with the Ultra-High, High and Medium price labels were considered acceptable overall when compared with the NONE label.

Conclusion: Even though all samples were the same, consumer perceptions of palatability traits were influenced by price labels. Although the higher price was perceived to have advantages in some quality aspects, consumers were still not more likely to purchase the higher-priced sample. This indicates that, even though consumers perceived the quality to be higher with a higher price label, the added quality did not justify their willingness to purchase it over the lower perceived quality and lower-priced samples.

Keywords: ground beef, labeling, palatability, price, purchasing

4 TRAINED SENSORY EVALUATION OF PLANT-BASED GROUND BEEF ALTERNATIVES IN COMPARISON WITH GROUND BEEF OF VARIOUS FAT PERCENTAGES

S. Davis^1*, K. Farmer¹, E. Beyer¹, K. Harr¹, S. Bigger², D. Thomson³, M. Chao¹, J. Vipham¹, M. Zumbaugh¹, M. Apley², D. Blasi¹, S. Ensley², M. Haub⁴, M. Miesner², A. Tarpoff¹, K. Olson¹, and T. O’Quinn¹, ¹Animal Science and Industry and ²College of Veterinary Medicine, Kansas State University, Manhattan, Kansas, USA; ³Animal Science, Iowa State University, Ames, Iowa, USA; ⁴Nutrition, Dietetics, and Health, Kansas State University, Manhattan, Kansas, USA, *sgdavis@ksu.edu

Objectives: The objective of this study was to determine whether current plant-based protein ground beef alternatives (GBA) offer similar palatability characteristics to ground beef (GB) patties of varying fat percentages.

Materials and Methods: Fifteen different production lots (n = 15/fat level) of 1.36 kg GB chubs of 3 different fat levels (10%, 20%, and 30%) were collected from retail markets in the Manhattan, KS, area. Additionally, GBA products including a soy- and potato-protein–based Foodservice GBA (FGBA), a pea-protein–based Retail GBA (RGBA), and a Traditional soy-protein–based GBA (TGBA) (n = 15 production lots/product) currently available at commercial channels were obtained from retail markets and a commercial foodservice chain. All GB and GBA treatments were hand-formed into 151-g patties and frozen at −40°C until analysis. Patties were thawed and cooked to an endpoint temperature of 71°C on a clamshell-style grill, cut into 6 wedges, and served within 5 min of cooking. Panelists (n = 120) were trained based on American Meat Science Association (AMSA) protocols and evaluated cooked internal color and beef and non-beef odor for each sample. Each sample was evaluated for juiciness, tenderness, beef flavor identity, beef flavor intensity, off-flavor, and texture. Each characteristic was evaluated on a continuous line scale, with anchors set at 0 and 100 and a midpoint of 50. All data were analyzed as a completely randomized design with treatment as a fixed effect.

Results: For all palatability traits evaluated, GB samples were different (P < 0.05) than all GBA samples. All GB samples were juicier, were less tender, had higher beef flavor ID and intensity ratings, were firmer, and had lower off-flavor ratings than all GBA samples (P < 0.05). Of the GBA samples, TGBA was the least juicy (P < 0.05). For tenderness, all GBA samples were rated more tender (P <0.05) than all GB samples, and for texture, all GB samples were firmer (P < 0.05) than all GBA samples. The RGBA and TGBA samples were the softest (P < 0.05). For beef flavor identity, all GB samples were rated higher (P < 0.05) than GBA samples. The GBA samples were all rated similar for beef flavor identity (P > 0.05). For beef flavor intensity, all GB samples rated higher (P < 0.05) than all GBA samples. For off-flavor intensity, all GB samples had less (P < 0.05) off-flavor intensity than all GBA samples. There were no differences (P > 0.05) among GB samples for off-flavor intensity. Panelists described the off-flavors of RGBA and FGBA as “fermented sour bean.” Panelists described the off-flavors of TGBA as “starchy.” For color, all GBA samples rated closer to well-done appearing (P < 0.05) than all GB samples, indicating that less red was visible in the internal center of the GBA samples. For beef odor, all GB samples rated substantially higher (P < 0.05) than all GBA samples. For non-characteristic beef odor, all GB samples rated much lower (P < 0.05) than all GBA samples.

Conclusion: These results indicate that GB samples had higher ratings than GBA samples for most palatability traits evaluated. Moreover, the GBA samples did not rate similarly to GB samples for visual or odor characteristics. This clearly indicates that the eating experience provided by the GBA is different than that provided by traditional GB. Thus, consumers who purchase GBA should not expect the same eating quality as they would receive with GB.

Keywords: alternative protein, ground beef, ground beef alternative, palatability, trained sensory panel

5 CHANGES IN CONSUMER SENSORY EVALUATION OF GROUND BEEF WHEN INFORMATION IS PROVIDED ABOUT THE PRIMAL SOURCE

K. Harr^1*, E. S. Beyer¹, K. J. Farmer¹, S. G. Davis¹, M. D. Chao¹, M. D. Zumbaugh¹, J. L. Vipham¹, and T. G. O’Quinn¹, ¹Animal Science and Industry, Kansas State University, Manhattan, Kansas, USA, *keaylah@ksu.edu

Objectives: The objective of this study was to evaluate the effect of providing information about the primal source of ground beef on the palatability of 80/20 ground beef patties.

Materials and Methods: Chubs (n = 15) of 80% lean/20% fat ground beef were procured from a commercial purveyor and were from the same production day and lot. Utilizing a patty former, ground beef was formed into 151.2 g (approximately 13 cm in diameter; 1 cm thick) patties. Chubs were randomly assigned to consumer panel sessions, and paired patties from a single chub were assigned randomly to one of 4 different primal blend types: ground chuck, ground round, ground sirloin, and store ground plus an unlabeled sample (NONE) to be used for consumer sensory analysis. For consumer sensory evaluation, consumers (N = 105) evaluated each sample on 0- to 100-point continuous line scales for juiciness, tenderness, texture, flavor liking, and overall liking, as well as gave their purchasing intent. Additionally, each consumer was asked to rate each of the palatability traits as either acceptable or unacceptable. While all samples were the same 80/20 ground beef, consumers were provided with additional labeling information prior to their evaluation of each sample both verbally and on a screen, with the NONE sample having no information provided. Finally, the change in consumer and acceptability ratings was calculated against the NONE sample. Finally, data were analyzed as a completely randomized design.

Results: Consumers rated ground chuck and ground sirloin more (P < 0.05) tender than ground round and NONE but similar (P > 0.05) to store ground. Moreover, ground chuck and ground sirloin were rated higher (P < 0.05) for juiciness than NONE. For flavor liking, store ground was similar (P > 0.05) to all treatments. When evaluating texture, consumers rated ground chuck higher (P < 0.05) than ground round, store ground, and NONE but similar (P > 0.05) to ground sirloin. Additionally, ground chuck, ground sirloin, and store ground were rated higher (P < 0.05) for overall liking than NONE. Consumers also indicated that they would be more likely (P < 0.05) to purchase ground chuck than ground round, store ground, and NONE. When evaluating the change in consumer ratings when information was given about the sample, all treatments had an increase (P < 0.05) in ratings across all the traits evaluated. Additionally, ground chuck had a greater (P < 0.05) increase in tenderness ratings when information was provided to the consumer in comparison with ground round and store ground. There were no differences (P > 0.05) in the percentage of samples rated as acceptable for tenderness, juiciness, flavor, texture, and overall liking. However, providing information about the primal source increased (P < 0.05) the percentage of samples rated as acceptable for juiciness for ground chuck and ground sirloin. Providing the primal source information to consumers did not (P > 0.05) increase the percentage of samples rated as acceptable for tenderness, flavor, texture, and overall liking.

Conclusion: Adding a primal source to the labeling of ground beef gives consumer a sense of added quality when consuming these products over those that do not have a primal source attached to their label. In the current study, adding a primal source identification positively shifted the consumers’ perception of the samples provided.

Keywords: beef, consumer, ground beef, labeling, palatability

6 IMPACT OF PLANT- AND ANIMAL-BASED PROTEINS ON SWINE ILEAL AND FECAL MICROBIOMES

T. W. Thompson^1*, N. Fanelli², H. Bailey³, A. Belk¹, J. Metcalf¹, H. Stein^2,3, and M. Nair¹, ¹Department of Animal Sciences, Colorado State University, Fort Collins, Colorado, USA; ²Department of Animal Sciences and ³Department of Nutritional Sciences, University of Illinois, Urbana, Illinois, USA, *twt16@colostate.edu

Objectives: The gut microbiome plays a direct role in human health and can influence health conditions ranging from obesity and diabetes to cancer. Previous research has indicated that the human gut microbiome is drastically modified when fed a diet containing only animal- or plant-based proteins. Whereas most of these studies have focused on traditional plant proteins (soy, legumes, etc.), none have evaluated the impact of the novel plant-based meat alternatives. Although the nutritional composition of the plant and animal proteins are comparable, a recent study suggested that the protein digestibility of animal-based products is greater when compared with their plant counterparts. Therefore, a cannulated swine model was utilized to investigate the impact of plant- and animal-based proteins on the ileal and fecal microbiome.

Materials and Methods: To best model the human digestive system, 10 ileal cannulated gilts were allotted to a 10 × 6 Yourden square with 6 feeding periods of 9 d. Ileal digesta were collected for 9 h on days 8 and 9, whereas fecal samples were collected on days 6 and 7. Treatment diets consisting of a burger (beef 80%, lean beef 93%, ground pork, Impossible Burger, or Beyond Burger) or a combination of the burger product along with a bun (beef 80%, pork, or Impossible) were used as the only source of nitrogen in a nitrogen-free ration. In addition, a nitrogen-free diet was served as the control. The ileal and fecal samples were processed with a fecal extraction kit and sequenced on an Illumina sequencing platform. Reads were generated and bioinformatically processed with the QIIME2 pipeline, with Shannon’s diversity and unweighted UniFrac phylogenetic metrics being generated with an alpha level set to 0.05.

Results: Significant differences (P < 0.05) in alpha and beta microbial diversity were found between the fecal and ileal microbial communities regardless of treatment diet. Although there might be some inherent differences in protein quality, no differences (P > 0.05) in alpha diversity were identified when evaluating treatment impacts on ileal and fecal microbiomes. For beta diversity, adding a bun to the protein sources had no impact (P > 0.05) on microbial populations compared with the protein source alone. When products were grouped based on protein type (plant or animal), differences in beta diversity (P = 0.01) were identified in the ileal microbiome. Fecal samples also had similar differences (P < 0.01) between plant and animal products. However, when fecal samples were evaluated on an individual basis, all animal proteins were found to be different (P < 0.05) from plant products, except the pork burger with a bun. The pork burger with bun was similar (P > 0.05) to the Impossible Burger in beta diversity.

Conclusion: Ileal and fecal microbiomes were different in the richness of bacteria with different species present in either group, suggesting that a fecal sample is not always representative of the whole gut microbiome. Although animal- and plant-based diets were found to be similar in alpha diversity, different microorganisms were found depending on the protein source provided. Our results indicated that that digestive tract microbial communities are impacted by the type of protein consumed (plant or animal).

Keywords: 16S ribosomal RNA, animal protein, fecal microbiome, ileal microbiome, plant-based protein

7 CHANGES IN CONSUMER SENSORY EVALUATION OF 80/20 GROUND BEEF WHEN ADDITIONAL LABELING INFORMATION IS PROVIDED

K. Harr^1*, E. S. Beyer¹, K. J. Farmer¹, S. G. Davis¹, M. D. Chao¹, M. D. Zumbaugh¹, J. L. Vipham¹, and T. G. O’Quinn¹, ¹Animal Science and Industry, Kansas State University, Manhattan, Kansas, USA, *keaylah@ksu.edu

Objectives: The objective of this study was to evaluate the effect of providing consumers with information related to different labeling terms on the palatability ratings of ground beef patties.

Materials and Methods: Chubs (n = 15) of 80% lean/20% fat ground beef from the same production lot and day were fabricated into 151.2-g (approximately 13 cm in diameter; 1 cm thick) patties utilizing a commercial patty former. Each chub was randomly assigned to one consumer panel session, and pairs of patties were randomly assigned to one of 8 different labeling terms: all natural (AN), animal raised without added antibiotics (WA), animal raised without added hormones (WH), fresh never frozen (FF), grass-fed (GF), locally sourced (LS), premium quality (PQ), and USDA organic (OR) plus an unlabeled sample (NONE) to be used for consumer sensory analysis. Consumers (N = 105) evaluated each sample for juiciness, tenderness, texture, flavor liking, and overall liking on 0- to 100-point continuous line scales. Additionally, each trait was rated as either acceptable or unacceptable, and consumers were asked to give their purchasing intent for each sample on a continuous line scale. Despite all samples being the same, prior to sample evaluation, consumers were provided the additional labeling information on the samples, with the NONE sample having no information provided. Finally, the change in ratings for each trait was calculated for consumer data compared with the NONE sample.

Results: There were no differences (P > 0.05) for tenderness, juiciness, texture liking, and overall liking ratings among the 9 different treatments. For flavor liking, consumers rated WA lower (P < 0.05) than AN, GF, LS, and OR but similar (P > 0.05) to WH, FF, PQ, and NONE. Also, consumers were less likely (P < 0.05) to purchase WA compared with AN, OR, FF, GF, LS, and OR. When evaluating the change in the ratings due to labeling, for consumers flavor liking scores, PQ had the lowest (P < 0.05) percentage change compared with AN, GF, LS, and OR, whereas PQ was similar (P >0.05) to the other treatments. Additionally, for overall liking, all treatments increased (P < 0.05) in ratings when labeling terms were provided. LS had increased (P < 0.05) ratings across all palatability traits as well as purchasing intent. No differences (P > 0.05) were found for the percentage of samples rated as acceptable for tenderness, flavor, and texture among labeling treatments. WA had a lower (P < 0.05) percentage of samples rated as acceptable for juiciness when compared with AN, WH, FF, LS, PQ, and OR. WA also had a lower (P < 0.05) percentage of samples rated acceptable overall when compared with AN, WH, FF, GF, LS, PQ, and OR, but WA were similar (P > 0.05) to NONE. Moreover, when evaluating the change in the percentage of samples rated as acceptable overall, disclosing WA to consumers resulted in a decrease (P < 0.05) in the percentage of samples rated as acceptable. Also, WA had the lowest (P < 0.05) change in the percentage of samples rated as acceptable for juiciness when labeling information was given when compared with AN, WH, FF, LS, PQ, and OR.

Conclusion: Adding additional labeling claims onto the packages of ground beef is meant to increase the overall appeal of the product to consumers. All labeling terms and claims in the current study saw a “brand lift” for palatability traits when the information was provided to the consumer prior to sample evaluation.

Keywords: beef, consumer, ground beef, labeling, palatability

8 EFFECTS OF COOKING METHOD ON VOLATILE FLAVOR COMPOUNDS OF BEEF STRIP LOIN STEAKS

C. A. Sepulveda^1* and M. F. Miller¹, ¹Animal and Food Science, Texas Tech University, Lubbock, Texas, USA, *cesar.sepulveda@ttu.edu

Objectives: Cooking variables such as heat transfer, cooking time, and others may produce different flavor compound profiles. Differences in consumer flavor perception can be explained by different concentrations of desirable and undesirable flavor compounds. Volatile compound collection and gas chromatography–mass spectrometry were performed to evaluate the effect of 4 different dry cooking methods on the production of flavor compounds and were contrasted with previous consumer panel results.

Materials and Methods: Forty-eight beef strip loins were selected representing 4 quality grades (Prime, Top [upper 2/3] Choice, Low [lower 1/3] Choice, and Select). Four 2.54-cm steaks were obtained from each striploin and randomly cooked with 4 different cooking methods: electric clamshell grill (CLAM), flat-top gas grill (FLAT), Charbroiler gas grill (CHAR), or Salamander gas broiler (SAL) (n = 12 steaks for each treatment combination). After cooking, longissimus lumborum pieces were submerged into liquid nitrogen for 30 s, and the frozen meat pieces were ground for 20 s using a food processor. Each powdered sample was packed, labeled, and stored at −80°C. Subsequently, 5 g of the powder was placed into a 15-mL clear glass vial, agitated at 65°C for 5 min in a Gerstel agitator (500 rpm). Then, an 85-μm film thickness carboxen polydimethylsiloxane solid-phase microextraction fiber was exposed in the headspace above the sample for 10 min. Following a 10-min extraction period, the solid-phase microextraction fiber apparatus was capped with a septum (LB-2, Supelco), and volatile compound spectra were obtained. Flavor compound concentrations were analyzed using the GLIMMIX procedure of SAS (version 9.4; SAS Institute Inc., Cary, NC); the experimental design was as split-plot with USDA quality grade as a whole plot factor, strip loin as the whole plot unit, and cooking method as a subplot factor.

Results: Flavor compounds were selected and quantified (ng/g cooked sample). There were no interactions between the cooking method and quality grade for any of the selected flavor compounds (P > 0.05). Pyrazines are powerful flavor compounds derived from Maillard reaction pathways. Steaks cooked on CHAR had the greatest (P < 0.05) concentration of pyrazines, followed by FLAT, then SAL, and the cooking method with the lowest pyrazine concentration was CLAM. Aldehydes and alcohols are usually associated with rancid off-flavors. CHAR presented a lower concentration of aldehydes like pentanal and heptanal and a lower concentration of the alcohol 1-hexanol. On the other hand, CLAM presented a higher concentration of 1-hexanol and pentanal; however, the concentration of 1-hexanol did not differ (P > 0.05) from SAL and FLAT. In the previous consumer panel study, CHAR presented higher (P < 0.05) flavor scores than FLAT and CLAM, but it did not differ from SAL.

Conclusion: Different cooking conditions evaluated allowed for the formation of different flavor compounds. CHAR produced more pyrazine flavor compounds known to contribute to roasted, grilled, and nutty characteristics (Mottram, 1991). On the other hand, Clam presented the lowest concentration of pyrazines and the highest concentration of some aldehydes and alcohols usually associated with off-flavors.

Keywords: cooking method, volatile flavor compounds

9 STUDENT PERFORMANCE USING A DIGITAL MEAT SCIENCE TEXTBOOK CORRELATES WITH STUDENT PERFORMANCE IN IN-PERSON INSTRUCTION

S. Zuelly^1*, B. Kim¹, Y. Guo¹, and M. Dennis¹, ¹Department of Animal Sciences, Purdue University, West Lafayette, Indiana, USA, *szuelly@purdue.edu

Objectives: The use of digital teaching technologies has increased dramatically in recent years. Digital textbooks can allow students to access course materials across multiple devices while providing instructors new opportunities to evaluate student learning. However, questions remain as to how student performance using digital textbooks relates to student performance when course content is delivered with in-person instruction. Therefore, the objective of this study was to determine whether correlations existed between digital textbook and in-class student performance for meat science lecture and laboratory courses.

Materials and Methods: A digital textbook (Meat Science: Conception to Consumption; Zuelly, 2020) was added to the required course materials for course ANSC 35100 (lecture, n = 159 students, Spring 2020) and course ANSC 35101 (laboratory, n = 62 students, Spring 2021) at Purdue University. Chapter topics were muscle biology, conversion of muscle to meat, meat quality, meat grading, carcass fabrication, processed meats, food safety, and careers in meat science. Each chapter ended with a quiz (TB Quiz) consisting of closed-ended questions and a critical thinking assignment (TB Assign) consisting of open-ended question(s) related to the chapter materials. TB Quiz and TB Assign were combined into a textbook total score (TB Total). For in-person lecture, students were required to complete 4 exams (Lec Exam), daily quizzes (Lec Quiz), and 2 assignments (Lec Assign), which were combined for a total lecture score (Lec Total). For in-person laboratory, students were required to complete weekly quizzes (Lab Quiz), one assignment (Lab Assign), and one exam (Lab Exam), which were combined for a total lab score (Lab Total). For the purpose of this analysis, all textbook data were removed from Lec and Lab scores in order to determine the correlations between textbook and in-class performance independently. Correlation analysis was used to compare TB Total, TB Quiz, and TB Assign to all in-class scores using PROC CORR in SAS (SAS version 9.4, SAS Institute Inc., Cary, NC).

Results: For lecture, positive correlations were found between TB Total and Lec Total (R = 0.7246), Lec Exam (R = 0.6660), Lec Quiz (R = 0.7323), and Lec Assign (R = 0.3870), all with P < 0.001. When evaluated separately, TB Quiz and TB Assign were similar in relationship to all lecture score categories. For laboratory, positive correlations were found between TB Total and Lab Total (R = 0.6215), Lab Exam (R = 0.2792), Lab Quiz (R = 0.6603), and Lab Assign (R = 0.6316), all with P < 0.001. When evaluated separately, TB Quiz and TB Assign were similar in relationship for Lab Total, Lab Quiz, and Lab Assign, but TB Quiz had a stronger correlation to Lab Exam (R = 0.4605) than TB Assign to Lab Exam (R = 0.1991).

Conclusion: These data indicate that student performance with this digital textbook correlates with in-person lecture and laboratory student performance of the course. The correlation was stronger for lecture, indicating that the use of the digital textbook as a wholesale replacement for in-person laboratory activities may be less impactful. Although these data indicate correlations in performance between the 2 delivery methods, further analyses—such as qualitative student responses to surveys and guided reflections—would be needed to determine whether students perceived that the use of the digital textbook enhanced their learning of the course materials.

Keywords: digital textbook, laboratory course, lecture course, student performance

10 IMPACT OF THE COVID-19 PANDEMIC ON INSTRUCTION IN ANIMAL AND FOOD SCIENCE COURSES

R. Ramanathan^1*, G. Mafi¹, M. R. Crosswhite¹, J. D. Crosswhite¹, M. Pfeiffer¹, and D. R. Stein¹, ¹Animal and Food Sciences, Oklahoma State University, Stillwater, Oklahoma, USA, *ranjith.ramanathan@okstate.edu

Objectives: The current pandemic, to an extent, has changed normal student learning. Although educational systems have been resilient, the current situation has put stress on students and instructors. The objective of the study was to discuss the effect of the pandemic on instruction in animal and food science courses.

Materials and Methods: All methodologies were approved by the Institutional Review Board. Eighteen questions were included in the survey instrument to assess the pandemic’s impact on instruction. The questions included in the survey were related to the type of courses taught, technology used, student engagement, and grade distribution. Qualtrics was used as a survey tool, and the survey link was sent out to animal and food science faculty from several universities (primarily meat science faculty). If different formats of teaching and technologies were used, the survey allowed faculty to record multiple responses.

Results: Forty-six responses were received. Prior to the pandemic, 91% of courses were taught in person, and 9% of courses were taught virtually. However, during the pandemic, 26.4% in-person, 34.7% virtual, and 38.9% hybrid course formats were taught. Thirty-four percent of faculty taught small (<25 students), 43% taught medium (26–99 students), and 22% taught large (>100 students) class sizes. Forty-five percent taught with lecture format only, 8% taught with laboratory format only, and 47% taught with both laboratory and lecture. Forty percent of faculty used Zoom, and 38% used university online classroom tools in teaching. However, 3.2% of faculty did not use any form of technology in teaching during the pandemic. Compared with the pre-pandemic period, 95% of faculty agreed that teaching was disrupted, 97% noted differences in student engagement, and 64% agreed there were differences in grade distribution. Sixty-one percent of faculty noted that they had less familiarity with digital tools for teaching before the pandemic. Interestingly, 70% of faculty agreed that they currently feel more comfortable teaching with technology, and 56% of faculty plan to continue to use technology post pandemic. Eighty percent of faculty made changes in the syllabus during the pandemic to accommodate changes in teaching.

Conclusion: The survey results indicate that there were significant teaching adjustments to accommodate changes with pandemic and federal health guidelines. However, some of the positive outcomes, such as the use of technology and recorded lectures, may provide additional teaching options post pandemic.

Keywords: COVID-19, pandemic, student learning, classroom technology, student engagement

11 DETERMINING THE IMPACT OF INTRODUCTORY MEAT SCIENCE EXTENSION PROGRAMS FOR PORK AND POULTRY

M. Dennis^1*, B. Brown¹, A. Mosiman², E. Rodgers², M. Kepler², S. Engleking², M. Edge², C. Carter², S. Davis², Y. Guo¹, D. Gadeken², and S. Zuelly¹, ¹Animal Sciences and ²Purdue Extension, Purdue University, West Lafayette, Indiana, USA, *szuelly@purdue.edu

Objectives: Recent events have increased the interest of individuals to learn and experience meat animal harvest, fabrication, and processing. However, education in these areas is generally not available outside of university settings. This has created an opportunity to develop extension activities to train extension educators, meat industry workers, meat animal producers, and consumers in the basic principles of meat science. Therefore, the objective of this program was to create an intensive, interactive extension program to teach attendees in the areas of animal harvest, fabrication, processing, and food safety.

Materials and Methods: The pilot extension program, Purdue University Boiler Butcher Basics, was developed for Spring 2021. The in-person, hands-on program had one 2-day workshop for pork (n = 9 attendees) and one 1-day workshop for poultry (n = 14 attendees). At the beginning of each workshop, electronic surveys (Qualtrics XM^TM) were completed using tablets (Pre-Program). Attendees were asked categorical questions related to demographics (gender, ethnicity, race, and age). Attendees were asked to score their initial knowledge of and confidence to perform the following parameters: general animal harvest techniques, general carcass processing techniques, food safety techniques, and species-specific (pork or poultry) harvest and processing techniques. At the end of the program, attendees were asked the same questions related to knowledge and confidence (Post-Program). All scores were determined using a 10-point slider scale allowing one decimal point, with descriptions above the scale (0 = not knowledgeable/confident at all, 10 = extremely knowledgeable/confident). Each species program was analyzed separately, with differences in Pre-Program and Post-Program knowledge and confidence questions analyzed using the PROC t test in SAS (version 9.4, SAS Institute Inc., Cary, NC), with significance determined at P < 0.05.

Results: Attendees of the pork program had significantly increased knowledge scores in the Post-Program survey for general animal harvest techniques (P = 0.0249), food safety techniques (P = 0.0375), and pork-specific harvest and processing techniques (P = 0.0461), in addition to increased confidence to perform scores for food safety techniques (P = 0.0367). Attendees of the poultry program significantly increased all knowledge and confidence to perform scores in the Post-Program survey (P < 0.001). The differences between the species is likely related to differences in experience among the attendees, as pork attendees reported a far greater range in knowledge and confidence questions, and qualitative information provided by the attendees suggested more practical experience.

Conclusion: The pilot program was designed to develop a curriculum, create resource materials, and gain feedback from participants in order to develop a permanent annual Boiler Butcher Basics program. Both pork and poultry programs were impactful at increasing attendees’ reported knowledge and confidence scores, but poultry was considerably more significant. This suggests that adding a quantitative question to the Pre-Program survey regarding experience would allow for improved analysis of this relationship. Furthermore, future programs will assign anonymous identifiers to attendee scores in order to strengthen the statistical model using a paired t test, and long-term surveys will determine lasting impacts to workforce development.

Keywords: extension, fabrication, harvest, training

12 VIRTUAL FFA/4-H MEAT JUDGING WORKSHOP FOR STUDENTS AND INSTRUCTORS DELIVERED VIA YOUTUBE AND ZOOM

G. Mafi^1*, C. Catrett¹, M. Scott¹, H. Nebgen¹, H. Roper¹, G. Harris¹, K. Hearn¹, A. Carlock¹, and R. Ramanathan¹, M. Pfeiffer¹, ¹Animal and Food Sciences, Oklahoma State University, Stillwater, Oklahoma, USA, *gretchen.mafi@okstate.edu

Objectives: There has long been a need to provide meat judging training materials for students across the country. Extension educators and agriculture instructors often lack training and expertise in meat judging; thus, providing clinics, workshops, or other materials to train teams could grow interest in meat judging and the meat industry. Effective methods of providing meat judging material at a time when teams are preparing for local, regional, and state events is critical. A few widely known training tools are available, but instruction at designated times besides summer camps or clinics have only been offered in one or two states. The COVID-19 pandemic caused most all learning and modes of delivery to shift to virtual. A positive result from this was that university academia, youth educators, and students adapted to using available resources. The objective of this virtual workshop (“Meat with Mafi”) was to provide an 8-week course to students and instructors in preparation for 4-H/FFA meat judging contests.

Materials and Methods: The topics covered were USDA beef quality and yield grading, beef and pork carcass and cuts evaluation, fabrication and retail identification, notetaking for reasons and questions. The workshop was divided into 8 sessions meeting on Zoom from February to April, concluding with a virtual contest. One week prior to each weekly virtual meeting, a YouTube video on the Meat with Mafi channel was sent to introduce the topic. The YouTube videos were recorded from PowerPoint presentations including complete instruction of the topic and practice carcasses, classes, and/or cuts. The video each week was 30 min to 2 h, and additional videos were provided for instructions on how to mark the 4-H/FFA Scansheet (JudgingCard, #480-4), as well as a video describing beef carcass grid pricing and placing pricing classes, and a retail cuts evaluation video. The weekly virtual meetings included review of material, additional instruction, practice classes, example reasons/questions, and break-out rooms for more interaction, practice classes, and question/answer sessions. Each weekly virtual session lasted from 45 min to 2 h and was recorded with links provided to review at any time. In total, over 10 h of YouTube video and 8 h of virtual meetings with 60 carcasses for yield and quality grading, 55 judging classes with questions/reasons, and over 150 retail ID were provided. At the end of the workshop, students were divided into divisions based on age and previous judging experience for a virtual contest.

Results: The workshop had 220 participants (180 students and 40 instructors) from 11 states. Students ranged in age from 10 to 18 years old (age 13 and under: n = 24; age 14: n = 30; age 15: n = 55; age 16: n = 45; and ages 17 and 18: n = 26). Students had participated in 0 to greater than 10 previous meat judging contests. Over half the students (n = 95) had never competed, and 30 had competed in 7 or more contests. After the contest, each instructor was mailed a flash drive with material for future training. Students surveyed at the conclusion said they would recommend or highly recommend the workshop and would like additional training in beef grading.

Conclusion: Based on positive feedback, the workshop will be offered annually and modified as needed.

Keywords: meat judging, students, virtual training

13 HOW MUCH WILL CELL-BASED MEAT COST?

G. Garrison^1*, W. Brorsen¹, and J. Biermacher², ¹Department of Agricultural Economics, Oklahoma State University, Stillwater, Oklahoma, USA; ²Agricultural Economist, Noble Research Institute, Ardmore, Oklahoma, USA, *greg.garrison@okstate.edu

Objectives: The objective of this research was to create an enterprise budget for a theoretical cell-based meat production firm and determine the breakeven price in the current market. Specific objectives included using equipment and service quotes from industry leaders to determine the total input cost of production and to determine the optimal output level given size restrictions, harvesting scenarios, and equipment maintenance, as well as performing a sensitivity analysis to determine price and output volatility and identify the best areas of production to cut costs.

Materials and Methods: An enterprise budget has been created using a combination of the annual costs of production and annual outputs to determine the wholesale cost per pound of production. This budget uses startup, production, employment, and transportation costs in addition to previously found (Specht, 2020) cell culture medium costs and harvesting scenarios. Bioreactor costs and cold storage construction are quoted from industry leaders in refrigeration manufacturing and assume a 10% cost of capital. Operating inputs such as water, labor, transportation, and packaging are estimated with respect to equipment use, industry averages, and location. Local sensitivity analysis is used on the cost of bioreactors, labor, and annual output to determine how individual changes impact the wholesale cost of cell-based meat.

Results: Assuming a 50% harvesting scenario with 10 harvests for each batch, meaning that 50% of the batch is harvested every few days to optimize the production process, the annual output for four 20,000 L bioreactors is 1.2 million pounds of cell-based meat, assuming constant production (Specht, 2020). Fixed costs of bioreactors, construction, insurance, computer infrastructure, and a facility lease are 10.3 million dollars annually, or $8.50/lb. Operating inputs, or variable costs, including water, electricity, labor, packaging, transportation, and the cell culture medium, are 21.25 million dollars annually, or $17.58/lb. The total cost of production is $26.06/lb of production. A sensitivity analysis found that 5%, 10%, and 20% reductions in the total output, likely attributable to broken equipment or inefficient production, corresponds with 5.25%, 12%, and 25% increases in the total wholesale cost holding all else equal. Analysis of the inputs, labor, bioreactors, and medium found that an overall cost reduction of $5/lb can be achieved through a 30% decrease in the cost of the bioreactors or the cell culture medium.

Conclusion: Given generous assumptions that include medium costs that are not yet possible, cell-based meat is expected to cost $26/lb in a wholesale market, but it could cost thousands of dollars in the modern landscape (Risner et al., 2021). Cost reduction in the industry will come from the cell-culture medium, bioreactors, and labor reduction. Water, electricity, and building space make up a small fraction of the overall production, meaning this industry could compete with scientific breakthroughs. This industry will struggle to compete with traditional meat, where lean cuts cost around $2/lb wholesale, and plant-based meat, where products cost less than $5/lb wholesale, but it could have a large impact in niche markets for exotic meats.

Keywords: alternative meats, cell-based meat, enterprise budget, sensitivity analysis

14 EVALUATING THE EFFECTS OF STORAGE CONDITION ON GREENHOUSE GAS FORMATION FROM GROUND MEAT

T. Price¹, J. Warren ², G. Mafi¹, A. Ramachandran³, and R. Ramanathan^1*, ¹Animal and Food Sciences, ²Plant and Soil Sciences, and ³Oklahoma Animal Disease Diagnostic Laboratory, Oklahoma State University, Stillwater, Oklahoma, USA, *ranjith.ramanathan@okstate.edu

Objectives: Previous research has determined greenhouse gas formation during various production phases of cattle, i.e., farm to plate. However, limited knowledge is currently available on greenhouse gas formation from discarded beef. The objective of this study was to evaluate greenhouse gas emissions, specifically carbon dioxide (CO₂), methane (CH₄), and nitrous oxide (N₂O), from aerobic and anaerobically stored ground beef in vitro.

Materials and Methods: Fresh shoulder clods were purchased from a local beef processor (n = 4). Shoulder clods were ground, formed into loaves, placed on foam trays with absorbent pads, and overwrapped with polyvinyl chloride film. Following 3 d of display in a coffin-style retail case, samples were stored in dark at 4°C (4, 8, and 11 d) to simulate meat storage conditions at home. During dark storage, samples were collected on days 4, 8, and 11 and incubated 21.5°C for 24 h ± 0.50 h in aerobic and anaerobic conditions for greenhouse gas analysis. The aerobic and anaerobic conditions simulate possible scenarios in a landfill. Aerobic samples were sealed with atmospheric oxygen, whereas anaerobic samples were flushed with 100% nitrogen gas in a vial. During retail display, surface color (a* values) was measured using a HunterLab MiniScan spectrophotometer. Total plate count was determined on days 4, 8, and 11, and MALDI Biotyper was utilized to characterize bacteria. A gas chromatography connected with a headspace analyzer was utilized to determine greenhouse gases. The data were analyzed using the Mixed Procedure of SAS (SAS Institute Inc., Cary, NC). There were 4 replications for all treatments.

Results: Surface color of loaves decreased (P < 0.05; day 0 a* values = 33.7 and day 3 a* values = 17.4) during retail display. Samples incubated in anaerobic conditions had a greater total plate count (P < 0.05) than aerobically incubated samples. The ground beef incubated in aerobic conditions had a greater concentration of CO₂, CH₄, and N₂O formation compared with the anaerobic condition. Dark storage time increased (P < 0.05) CO₂ concentration but not CH₄ and N₂O levels. Bacterial characterization identified Carnobacterium divergens, Hafnia alvei, Lactobacillus sakei, Lactobacillus sakei, and Yersinia enterocolitica.

Conclusion: The results suggest that oxygen content and dark storage time can impact the greenhouse gas formation of ground beef products. To the best of our knowledge, the current research is the first report on greenhouse gas potential from ground beef. The study indicates the possible effect of discarded meat on the environment.

Keywords: beef color, environment, greenhouse gas

15 ECONOMIC LOSSES DUE TO BEEF DISCOLORATION

R. Ramanathan^1*, L. H. Lambert², M. N. Nair³, B. Morgan³, G. Mafi¹, and M. Pfeiffer¹, ¹Animal and Food Sciences and ²Agricultural Economics, Oklahoma State University, Stillwater, Oklahoma, USA; ³Animal Science, Colorado State University, Fort Collins, Colorado, USA, *ranjith.ramanathan@okstate.edu

Objectives: Consumers associate a bright cherry-red color of beef with freshness and wholesomeness. Any deviation from a bright red color leads to a discounted price or discarded meat. A previous report by Dr. Gary Smith and others in 2000 noted that the US beef industry lost $1 billion annually due to discoloration. Since 2000, the meat industry has adopted several practices, including case-ready meat to enhance efficiency in meat merchandise. However, limited data are currently available on the economic losses due to retail beef discoloration. Furthermore, meat discarded in retail stores results in societal loss of resources invested in producing meat and negative externalities that affect the environment. Therefore, the objective of the study was to determine economic losses, the amount of beef discarded, and natural resource wastage due to beef discoloration.

Materials and Methods: Fifty-two-week data of total beef sales, total beef discarded, and discounted sale value were collected from 2 national retail chains and 1 retail store. The 2 retail chains were located throughout the US, and the one retail store was located in the Southern US. All data were collected from meat store managers and front-line staff. No consumer data were collected. The US beef system life cycle parameters from published literature such as water, energy consumption, and carbon emissions along the beef production value chain were calculated to assess the impact of discarded meat on natural resources. The value chain includes feed production, cow-calf production, feedlot operations, packing, and case-ready operations. The data from 3 stores were modeled to calculate annual loss due to discoloration from the US retail beef sales.

Results: The data indicated that total beef sales from 2 major retail chains and 1 retail store for the 52-week period was 1.1 billion pounds of steaks and ground beef. This amount of beef corresponds to approximately 10% of total retail sales in the US. The amount of beef discarded from 2 major retail chains and 1 retail store corresponds to 29.6 million pounds. Based on modeled data, the amount of beef discarded due to discoloration from the US retail beef corresponds to 350 million pounds. This results in an annual loss of $2.1 billion due to discoloration in the US beef industry. The amount of beef discarded was calculated to estimate equivalent animals and associated natural resources lost. Results show that a 1% decrease in discolored meat across 3 retail stores could reduce natural resource and environmental impacts by 341 million L of water, 138 million mega Joules of energy, and 5.8,000 tons of carbon dioxide equivalent emission consumed along the beef upstream value chain.

Conclusion: Beef discoloration is an inevitable process. The current research indicates that even with the advancement in technologies, meat discoloration during retail display can have a significant economic and environmental impact. Therefore, any novel technologies to improve meat color stability could improve beef production’s sustainability and limit wastage of nutritious beef.

Keywords: beef color, economic losses, environmental impact

16 A PILOT STUDY ON CHARACTERIZATION OF HIDE MICROBIAL RESISTOMES OF ANIMALS IN THE DAIRY AND BEEF CATTLE PRODUCTION SYSTEMS

L. Yang^1* and X. Yang¹, ¹Department of Animal Science, University of California, Davis, Davis, California, USA, *ylhyang@ucdavis.edu

Objectives: Antimicrobial resistance is an emerging public health concern. Animal hides may be contaminated by feces shedding antimicrobial resistant bacteria directly from its host, via the interaction with other animals or the environment. The contaminated animal hide may subsequently become a potential source of antimicrobial resistant bacteria contamination in dairy and meat production. The objective was to characterize the resistome of animal hides and compare it with the resistome of the corresponding livestock production environment.

Materials and Methods: Thirty-six samples were collected from 3 facilities, namely UC Davis Beef Cattle Feedlot, Dairy Farm, and Sierra Foothill Research & Extension Center, which is a rangeland. The sample matrices included composite fecal samples, swabs from animal hides, and pen floor surfaces (4 samples/matrix/production environment). Entire microbial DNA was extracted for each sample and sequenced on Illumina NoveSeq 6000 platform. Qualified reads were aligned to the MEGARes 2.0 using Burrows-Wheeler Aligner. The relative abundance of resistome data were calculated and reported as transcripts per kilobase million. Shannon’s diversity of resistomes was calculated applying vegan 2.5 in R 3.6. A one-way analysis of variance was performed to compare the Shannon’s diversity of the resistome at antimicrobial resistance genes in different sample matrices within each production environment. The analysis of similarity (ANOSIM) for the resistome data at the mechanism level was performed in the vegan package in R version 4.1. The alpha level was defined as 0.05.

Results: Across all samples, 29,890,036 reads were aligned to 916 antibiotic resistance genes, classified into 39 classes of resistance and 95 mechanisms. In cattle hide samples collected from the dairy, rangeland, and feedlot, the most abundant 3 classes of antimicrobials were MLS, aminoglycosides, and oxazolidinone, accounting for 73.26%, 72.72%, and 67.70% of the resistomes, respectively (Figure 1). In addition, the most abundant resistance mechanism identified in the hide samples across all 3 facilities was macrolide-resistant 23S ribosomal RNA (MLS23S) mutation. These results were not surprising because both MLS and aminoglycosides are commonly used in dairy and beef cattle production to treat bovine respiratory diseases and mastitis. Furthermore, at the mechanism level of resistance, differences in resistome composition (ANOSIM P < 0.05) were detected in all sample matrices within each production environment. The greater resistome separation among sample matrices was detected in samples collected from the feedlot (ANOSIM R = 0.67) and the rangeland (ANOSIM R = 0.69), compared with those collected from the dairy farm (ANOSIM R = 0.34). The results indicated that feces may not be the only source that form the resistome on animal hides. The Shannon’s diversity of resistomes of animal hide samples was not different (P > 0.05) from that of the rest of the sample matrices in each livestock production environment.

Figure 1.

Relative abundance of top 10 antimicrobial resistant classes in different samples collected from three livestock production environment.

Conclusion: This study characterized the resistomes of the animal hide in the selected production environments. In regard to the levels of resistomes, although the diversity was similar in hide and other samples, the composition of resistome of animal hide was still very different from those in cattle feces and pen floors within each production system. Therefore, a large-scale study is needed to better understand the formation of the hide resistome from the animal host and the environment.

Keywords: antimicrobial resistance, dairy and beef cattle production systems, resistome

17.1 TISSUE CONCENTRATIONS FROM BEEF CATTLE FED LUBABEGRON FUMARATE FOLLOWING VOLUNTARY REMOVAL FOR MULTIPLE TIMEPOINTS

P. Rincker^1*, G. Vogel¹, J. Allen¹, M. Edmonds², N. Van Engen², and C. Herr¹, ¹Elanco Animal Health, Greenfield, Indiana, USA; ²LLC, Johnson Research, Parma, Idaho, USA, *phil.rincker@elancoah.com

Objectives: Lubabegron fumarate (LUB; Experior™, Elanco Animal Health) is a feed additive approved for the reduction of ammonia gas emissions per pound of live weight and hot carcass weight (HCW) in beef steers and heifers. A 72-d study was conducted to quantify tissue residues of finishing beef cattle fed LUB.

Materials and Methods: Feedlot steers (n = 700, 529.5 ± 8.8 kg body weight [BW]) were allocated in a randomized complete block design to 7 treatments within 10 blocks (10 animals/pen, 10 pens/treatment) including a control (CON) and 6 LUB treatments followed by voluntary removal periods. LUB was fed for 56 d followed by removal periods of 0, 2, 4, 6, 8, or 16 d. Treatments were stagger started and harvested on a common date. Tissue samples including diaphragm, liver, rumen, reticulum, and omasum were collected from 5 animals per treatment, and all were handled using commercial processing procedures. LUB concentration was determined by liquid chromatography–tandem mass spectrometry with a limit of quantification (LOQ) at 1 μg/kg using parent LUB as the analytical marker. The limit of detection (LOD) was 0.4 μg/kg for liver and 0.5 μg/kg for all other tissues. Means were calculated using the extrapolated value for samples between the LOQ and LOD and one-half the LOD as an estimate for non-detectable (ND) samples when other samples within the treatment group were above the LOQ.

Results: All individual liver samples contained less than 2 μg/kg LUB at 0-d removal and were ND after a 2-d removal. All individual diaphragm samples contained less than 1 μg/kg LUB at 0 d and were ND following a 4-d voluntary removal period. Rumen and reticulum samples displayed similar residue levels to each other having declined to less than 1 μg/kg LUB following 4-d removal and became ND following a 6-d removal. Omasum residue levels were higher, likely owing to visible feed contamination between the folds of the organ following commercial processing. Ammonia gas emissions were calculated using the equation published by Brown et al. (Applied Animal Science, 2018). Calculated cumulative ammonia gas emissions over the 72-d study were greater (P < 0.001) for CON (6,204 g/head) than for LUB (5,202 to 5,348 g/head). Final BW was increased (P < 0.001) by LUB (652.7 to 658.2 kg) compared with CON (640.0 kg). Duration of removal had no impact on calculated cumulative ammonia gas emissions (P > 0.20) or final BW (P > 0.20). HCW was greater by an average of 16.3 kg (P < 0.001) when LUB was fed. HCW was 394.6, 409.6, 411.0, 413.2, 410.5, 412.8, and 408.2 kg for CON and 0, 2, 4, 6, 8, and 16 d of removal treatments, respectively. The HCW response by duration of lubabegron removal was quadratic (P = 0.042).

Conclusion: These data indicate that tissue residue levels from cattle fed LUB are relatively low and decline rapidly following removal. Additionally, this information supports that LUB should reduce ammonia gas emissions per pound of live and HCW and that this reduction may be sustained for up to 16 d following removal.

Keywords: ammonia, body weight, feedlot cattle, lubabegron, residue

18 EFFECTIVENESS OF FOOD-GRADE COATING TREATED NETS AFTER VARIOUS DRYING METHODS AT CONTROLLING MITE GROWTH ON DRY-CURED HAMS

S. White^1*, Y. Campbell¹, S. Smith¹, C. Freeman², T. Phillips³, and W. Schilling¹, ¹Food Science, Nutrition, and Health Promotion and ²School of Human Sciences, Mississippi State University, Mississippi State, Mississippi, USA; ³Entomology, Kanas State University, Manhattan, Kansas, USA, *white.sadie@yahoo.com

Objectives: Tyrophagus putrescentiae, known as the ham mite (Schrank), is the most difficult pest to control in the dry-cured ham industry. Formerly, methyl bromide fumigation was used to control mite infestations, but it is classified as an ozone-depleting substance; therefore, use has been limited. Food-grade propylene glycol (PG) coating treated ham nets have been successful in controlling ham mite growth and reproduction, but there are several application challenges that can be improved. Among these are the costs of shipping as wet coated nets are heavy and costly to ship; these wet nets can be inconvenient for commercial dry-cured ham manufacturers. The objective of this research was to determine the effectiveness of food-grade coating treated ham nets that were dried using different drying methods at controlling ham mites.

Materials and Methods: Polyester nets were coated with a food-grade solution (wet coated net [WN]) of 40% PG, 1% PG alginate, and 1% carrageenan, using methods that were previously developed in our laboratory. Two treatments were dried on stainless steel racks (B085C6G8BM; P&P CHEF, China) in a convection oven (SCVX20E; Hobart, Chattanooga, TN) at 93.3°C, the first for 7 min and the second for 20 min. The third treatment was dried at 25°C on the counter in the laboratory for 24 h. The 3 dried net treatments were then tested for their efficacy at controlling mites against 3 control treatments: uncoated polyester net (negative control), coated polyester net (positive control), and no net (negative control). The 6 treatments tested on the ham cubes were as follows: no net (C), coated and wet net (WN), uncoated net (CN), oven dried for 7 min (OD7m), oven dried for 20 min (OD20m), and counter dried for 24 h (CD24h). Ham cubes (2.5cm × 2.5cm × 2.5cm) were wrapped in the ham nets (n = 5/treatment) and inoculated with 20 adult mites, with the exception of the C treatment. The ham cubes were stored in ventilated jars at 25°C and 70% relative humidity for 14 d. The total mite counts were taken on day 14.

A randomized complete block design with 2 replications was used to determine whether differences existed (P ≤ 0.05) among treatments. Duncan’s multiple range test was used to separate treatment means when differences existed.

Results: The OD7m (2 mites), CD24h (3 mites), and WN (2 mites) treatments had fewer mites (P ≤ 0.05) than the OD20m (38 mites) and CN (45 mites) treatments. The C treatment had 183 mites, a greater number of mites (P ≤ 0.05) than all other treatments. The OD20m did limit (P ≤ 0.05) mite growth when compared with the C but was not as successful (P ≤ 0.05) as OD7m, CD24h, or WN. This may be a result of PG evaporation. During the drying process, the OD7m and CD24h treatments lost 37.3% and 36.5% of their starting weights, respectfully, whereas the OD20m lost 72.0%. The greater loss (P ≤ 0.05) for the OD20m likely affected the treatment’s efficacy as the PG evaporated more during drying whereas the OD7m and CD24h retained more PG during drying.

Conclusion: Nets that were dried by 36%–37% controlled mites but decreased product weight, which leads to easier shipping and handling by the industry. Further research could be conducted to determine the maximum weight loss that can be achieved during drying while still effectively controlling mites.

Keywords: dry-cured ham, drying, food-grade coating, ham mites, ham nets

19 PHYSICAL EFFECTS OF CARROT FIBER AS A BINDER IN COOKED SAUSAGE

J. A. Johnson^1*, L. A. Kinman¹, A. Cassens¹, W. Owsley¹, and J. Heller², ¹Department of Animal Science and ²Department of Management, Tarleton State University, Stephenville, Texas, USA, *jessica.johnson08@go.tarleton.edu

Objectives: Binders and extenders are commonly used in sausage formulations to reduce costs, increase cook yield, and improve texture. Soy protein (SP) and non-fat dry milk (NFDM) are 2 common binders used in sausage processing. However, an increase in the amount of allergen mislabeling incidents and consumer concerns have pushed the demand for an allergen-free alternative. The objective was to establish the effectiveness of carrot fiber (CF) in cooked chicken and pork sausages as an alternative to SP and NFDM.

Materials and Methods: Chicken breast and thigh meat were coarse ground using a 12.5-mm plate. Coarse ground meat was then added to the grinder with 1.5 L of water and a seasoning blend that consists of curing salts (A.C. Legg cure 6.25% Sodium Nitrite), sodium erythorbate, and salt. The formulation was mixed until blended and fine ground through a 9.5-mm plate. The blend was divided into seven 4.5-kg batches and randomly assigned a binder treatment: no binder (control), CF, NFDM, or SP at either 2% or 3.5% inclusion rates. Pork picnic and ham trim were processed in the same manner. Formulations were stuffed into 32-mm diameter cellulose casings and cooked to an internal temperature of 71°C, cold showered, and stored in a cooler (4°C) for 24 h, vacuum packaged and frozen. Texture profile analysis was executed in triplicate. Sausages were thawed at 5.5°C for 24 h, placed in an aluminum-lined baking pan, covered in foil, and reheated in an oven at 121°C to an internal temperature of 71°C. The texture profile analysis variables (hardness, springiness, cohesiveness, chewiness, and resilience) were established using model TA.XTPlus. Statistical analysis was conducted using Statistix (Version 10.0 USA). Analysis was set up as a completely randomized design. The independent variable was binder treatment, and the dependent variables were the texture profile variables. Least-squares means were separated for significant main effects. Differences were detected at α = 0.05.

Results: Chicken sausages made with CF 2% and 3.5% were harder (P < 0.05) than all other treatments and were less resilient. Springiness was not different (P > 0.05) among treatments. Sausages made with CF 3.5% were less cohesive (P < 0.05) than NFDM 2%, 3.5%, SP 3.5%, and the control. Additionally, CF 3.5% was chewier (P < 0.05) than all other treatments. However, CF 2% was similar (P > 0.05) in chewiness to NFDM 3.5% and SP 3.5%. Pork sausages prepared with CF 3.5% were less springy (P < 0.05) than all other treatments. Additionally, CF 3.5% was the same (P > 0.05) as NFDM 3.5%, SP 2%, and 3.5% in hardness values. However, CF 2% was not as hard (P < 0.05) as NFDM 2%, NFDM 3.5%, and SP 3.5%. Also, CF 2% was similar (P > 0.05) in cohesiveness to SP 2%, SP 3.5%, and the control, with CF 3.5% the least (P < 0.05) cohesive and resilient. Conversely, CF 2% was less chewy (P < 0.05) than NFDM 2% and NFDM 3.5%. Lastly, CF 3.5% was chewier (P < 0.05) than the control but less chewy than NFDM 2% and NFDM 3.5%.

Conclusion: In conclusion, the results suggest that chicken and pork sausage made with CF 3.5% was harder and chewier than the other treatments, which may mean that CF does not make an adequate replacement for SP or NFDM. However, CF 2% created a similar texture profile as NFDM and SP at either concentration, which may make the 2% inclusion rate of CF a more practical option for a replacement.

Keywords: binder, carrot fiber, sausage, texture profile analysis

20 TOTAL REPLACEMENT OF ANIMAL FAT IN COARSE-GROUND PORK SAUSAGES BY NOVEL BIPHASIC GELS CONTAINING HIGH-OLEIC SOYBEAN OIL

N. D. Kibler^1*, N. C. Acevedo², K. Cho², E. A. Zuber¹, Y. B. Carvajal², and R. Tarté^1,2, ¹Department of Animal Science and ²Department of Food Science & Human Nutrition, Iowa State University, Ames, Iowa, USA, *rtarte@iastate.edu

Objectives: The study objective was to assess the potential of a novel gelatin/rice bran wax biphasic gel (BPG) system containing high-oleic soybean oil (HOSO) to replace fat in coarse-ground meat products, using smoked sausage as a model.

Materials and Methods: BPG systems were made by combining an oleogel (OG) phase (92.5% HOSO, 7.5% rice bran wax) and a hydrogel (HG) phase (water and either 7% [HG7] or 8% [HG8] pork skin gelatin). Control sausages were formulated to a target of 27.5% fat and were made with pork picnic and 42 trimmings (C1), and lean pork knuckles and pork back fat (C2). BPG treatments were made with pork knuckles and one of the following 4 BPG in replacement of 100% of the pork fat: 70% OG/30% HG7 [7:3-7G]; 70% OG/30% HG8 [7:3-8G]; 60% OG/40% HG7 [6:4-7G]; and 60% OG/40% HG8 [6:4-8G]. BPG gels were ground in a meat grinder, just like the meat raw materials. Cooked sausage links were vacuum packaged, stored at 0°C–2°C for 98 d, and analyzed every 14 d for external and internal color (CIE L*a*b*), instrumental texture (texture profile analysis and Warner-Bratzler shear force), and lipid oxidation (TBARS method) and on days 14, 42, 70, and 98 for sensory evaluation (10-member trained panel, 15-cm unstructured line scale). Fatty acid profile was done by gas chromatography–mass spectrometry. The study was replicated 3 times. Statistical analysis was conducted as a mixed model using JMP Pro version 15.1.0 (SAS Institute Inc., Cary, NC), with significance set at P < 0.05.

Results: Cook/chill yield and pH were unaffected by treatment (P ≥ 0.05). Treatment effects on external L* and a* were not significant (P < 0.05). For internal L*, 6:4 BPG > 7:3 BPG > C1/C2, with the reverse being observed for a* (P < 0.05), indicating that BPG resulted in lighter and less red products and that an increase in the HG phase of the BPG gels increased product lightness and reduced redness. Internal b* was highest in 7:3 BPG and lowest in 6:4 BPG, likely owing to the yellowish hue of HOSO. Samples were lighter at day 56, day 70, and day 98 than at day 0, redder at day 70 than at day 0, and yellower after day 0. Texture profile analysis hardness was lower in C1 than 7:3 BPG, and Warner-Bratzler shear force was lowest in C1 (P < 0.05). TBARS values were lower for the controls than for the BPG treatments (P < 0.05), and all remained under 0.90 and were stable over time (P ≥ 0.05). For sensory attributes, C1/C2 > 7:3 BPG > 6:4 BPG for Smoked Aroma and Smoked Flavor, with the inverse being observed for Off-aroma and Off-flavor. First Bite Firmness was lowest in C1 and higher in 6:4-8G than in 7:3 BPG. For Creaminess, 6:4 BPG > 7:3 BPG > C1/C2, and Moisture Release was higher in C1 and C2 than in BPG treatments. External Color was darker in 6:4 BPG. For External Appearance and Internal Appearance, 6:4 BPG had more visible discrete particles, whereas 7:3 BPG were not different from both controls.

Figure 2.

Conclusion: We believe that this study is the most successful attempt to date at mimicking animal fat in a coarse-ground meat product. Successful application of this technology will involve manipulating the mechanical properties of the BPG gels, which are determined by choice of gelators and OG:HG phase ratio. Because BPG are lower in fat than animal adipose tissue, fat content of the final products is also reduced. Use of HOSO as the oil source of the BPG results in a more favorable fatty acid profile. This technology also has potential in other food applications in which mimicking semisolid fats is desired.

Keywords: biphasic gel, coarse-ground meat product, fat replacement, high-oleic soybean oil, sausage

21 PHYSICAL EFFECTS OF CITRUS FIBER AS A NATURAL ALTERNATIVE TO SODIUM TRIPOLYPHOSPHATE IN MARINATED BEEF

K. R. Howard^1*, L. A. Kinman¹, A. M. Cassens¹, C. Runyan¹, and B. Poe², ¹Animal Science and Veterinary Technology and ²Agricultural and Consumer Sciences, Tarleton State University, Stephenville, Texas, USA, *kendal.howard@go.tarleton.edu

Objectives: Phosphates are commonly used in marination to increase cook yields, water-holding capacity, and juiciness. Clean labeling trends have resulted in a preference for more natural and less processed meat products. The functionality of citrus fiber (CF) displays potential success as a phosphate replacement in processed meat. The objective of this study was to evaluate the physical effects of CF as a natural phosphate replacer in enhanced transversus abdominis muscle.

Materials and Methods: Beef skirt steaks (transversus abdominis) (Institutional Meat Purchase Specifications #121D) were denuded and randomly assigned to one of 5 marination treatments: no phosphate (control), CF and sodium tripolyphosphate (STPP) at either 0.25% or 0.5% formulation rate. Salt level was consistent among all treatments; water amount varied based on formulation rate. Steaks were weighed initially and vacuum tumbled at 15 psi for 15 min, at approximately 45 RPM. Samples were weighed immediately and 15 min after enhancement. Steaks were vacuum packaged and placed in a retail display case for 10 d for retention or frozen until slice shear force (SSF) analysis. For retention, steaks were initially weighed in the bag (packaged weight) and weighed after bag removal (unpackaged weight), and the bag was rinsed, dried, and weighed (bag weight). Net weight was calculated by subtracting the bag weight from the packaged weight. Purge weight was calculated by subtracting the unpackaged weight from the net weight. Purge percentage was calculated by dividing the purge weight by the steak net weight. The SSF was executed in duplicate. Steaks were thawed at 5.5°C for 24 h, individually weighed, placed in an aluminum-lined baking pan, covered in foil, and cooked in an oven at 177°C to an internal temperature of 71°C. After cooling for 1 h, cooked samples were weighed, and cook yield percentage was calculated by dividing cooked weight by initial weight. Steaks were chilled for 18 h at approximately 2°C to 4°C. One-cm-thick, 5-cm-long slices were removed from each cooked steak parallel to the muscle fiber using a 45° slice box and a double blade knife. Slices were sheared once perpendicular to the muscle fibers using model TA.XTPlus. Statistical analysis was conducted using Statistix (Version 10.0 USA) for SSF. Analysis was set up as a completely randomized design. Least-squares means were separated for significant main effects. Retention data were analyzed using the PROC GLM procedure of SAS (version 9.4; SAS Institute Inc., Cary, NC). Differences were detected at α = 0.05.

Results: Pickup percentage, 15-min retention, and overall retention were similar (P > 0.05) among treatments. For SSF analysis, steaks marinated in CF 0.25% and 0.5% had higher (P < 0.05) shear force values compared with steaks marinated in STPP, indicating a tougher product. Also, cook yield was influenced by treatment. CF 0.25% had lower cook yield (P < 0.05) compared with STPP of either inclusion but was similar (P > 0.05) to CF 0.5%. CF 0.5% was similar (P > 0.05) to STPP 0.25% in cook yield percentage.

Conclusion: The results suggest that beef skirt steaks marinated in CF were tougher than other treatments, which may mean that they do not make a suitable replacement for STPP. However, CF 0.5% yielded a similar cook yield as STPP 0.25%, which may make the 0.5% inclusion rate of CF a more practical replacement for increasing cook yield of beef products.

Keywords: beef, citrus fiber, marination, sodium tripolyphosphate

22 COMPARISON OF LAURIC ARGINATE ESTER AND ACIDIFIED SODIUM CHLORITE AS POST-LETHALITY INTERVENTIONS IN A SPRAYED LETHALITY IN CONTAINER SYSTEM ON PROCESSED MEATS

A. Curtis¹, R. Cope¹, E. Behrends¹, L. Branham¹, and J. Kellermeier^1*, ¹Agriculture, Angelo State University, San Angelo, Texas, USA, *jkellermeier@angelo.edu

Objectives: The objectives of this study included 1) evaluating the effectiveness of acidified sodium chlorite (ASC) and lauric arginate ester (LAE) on Listeria innocua and 2) measuring quality characteristics of pork German sausage treated with the same antimicrobials.

Materials and Methods: Pork German sausage (NAMP# 811 Smoked Sausage) was utilized for all portions within the study. All procedures involving human subjects were approved by the Angelo State University Institutional Review Board committee (#BRA-073119). The antimicrobial treatments used in this study were ASC and LAE. Pork German sausage links were inoculated with Listeria innocua, a nonpathogenic surrogate for Listeria monocytogenes (n = 135). The original inoculum contained 8.61 log₁₀CFU/mL. Inoculation was performed based on the procedures of Taormina and Dorsa (2009). Five links were randomly selected and tested from each treatment (n = 15) following 2 h of storage (day 0) and plated to establish an initial bacterial count. Twenty links from each treatment were randomly assigned to day 1 and day 14 analysis (n = 60). For trained sensory analysis, non–Listeria-inoculated links were randomly assigned to one of 2 treatments, ASC or LAE (n = 140). Two milliliters of each treatment was pipetted into each vacuum package following the insertion of the sausage and then vacuum sealed to mimic the Sprayed Lethality in Container system. Sensory evaluation was conducted using a triangle test to identify which sample was different. Color of the pork German sausage was measured using a Minolta Colorimeter. These values were used to determine whether any color fading occurred to the exterior portion of the sausage because of the antimicrobial applications. Data were analyzed using the MIXED models procedures of SAS (SAS Institute Inc., Cary, NC). Least-squares means were computed for each dependent variable and statistically separated by a pair-wise t test with predetermined α = 0.05. Results from the triangle test were analyzed using a chi-square analysis in the Frequency Procedure of SAS.

Results: On day 0, sausage treated with LAE (7.18 log₁₀CFU/package) had a significantly higher concentration (P < 0.05) than both ASC (6.42 log₁₀CFU/package) and CON (6.59 log₁₀CFU/package). On day 1, the control (6.84 log₁₀CFU/package) had a significantly higher concentration (P < 0.05) when compared with the ASC-treated (6.74 log₁₀CFU/package) and LAE-treated (6.54 log₁₀CFU/package) sausage. All 3 treatments differed on day 14, with ASC having the lowest Listeria innocua concentration and the control having the highest (P < 0.05). Although sausage treated with ASC had the lowest L. innocua concentration among all 3 treatments on day 14, LAE-treated sausage had the greatest log reduction. The triangle sensory test showed no significant differences between ASC and LAE, with the average correctly identified samples being 32.99% and 33.68%, respectively. A statistical difference (P < 0.05) was found in the b* value of LAE-treated sausage, which was more yellow in color than those treated with ASC (37.84 and 36.48, respectively). The L* and a* values between treatments were not significantly different.

Conclusion: In conclusion, ASC and LAE may both be used as post-lethality interventions in a Sprayed Lethality in Container system without negatively impacting sensory characteristics of ready to eat foods and processed meats in the meat industry.

Keywords: acidified sodium chlorite, lauric arginate ester, Listeria, ready to eat, Sprayed Lethality in Container

23 MODIFIED ATMOSPHERE PACKAGING DOES NOT ADEQUATELY PRESERVE HIDES FOR GELATIN PRODUCTION

G. Allen^1*, A. Manzoor¹, J. Brown¹, C. Hersom¹, C. Brown¹, and J. M. Scheffler¹, ¹Animal Sciences, University of Florida, Gainesville, Florida, USA, *jmscheff@ufl.edu

Objectives: Efficient utilization of animal byproducts is critical to both economic viability and sustainability of meat processors. Bovine hides can be further processed into leather, pharmaceutical, cosmetic, household, and industrial products. However, small processors have limited ability to supply the volume needed to be profitable. Worse, hides that are not sold must be disposed of with additional cost. Developing a method to temporarily preserve hides and allow for accumulation may help overcome this challenge. Beef hides are contaminated with microorganisms from a range of sources such as feces, dirt, water, and soil that quickly result in putrefaction of the hide. The objective of this study was to assess the efficacy of modified atmosphere packaging to temporarily preserve hides to allow for accumulation and subsequent processing into gelatin.

Materials and Methods: Four hundred square-centimeter sections (20 cm × 20 cm) were cut from fresh beef hide. Sections were staked 6 high and placed into 3 mil polyethylene bags. Bags were randomly assigned to a sealing method including control (sealed with ambient air), vacuum flush with nitrogen, and vacuum seal. Bags were stored at 15°C with air circulation to mimic conventional storage. On days 0, 4, 7, 14, and 21, six bags per treatment were removed, and a representative section was plated for total plate count enumeration. The remaining sections were unhaired with aqueous lime and thoroughly washed with water and neutralized. Sections were cut into 1-cm strips before gelatin extraction in 80°C water. Extracted gelatin was dialyzed with water for 48 h, freeze dried, and then reconstituted to determine bloom strength. The study was replicated 3 times. Statistics were analyzed using SAS JMP (SAS Institute Inc., Cary, NC); the model included day, packaging, and their interaction. Significant difference was determined at P < 0.05.

Results: The different packaging methods showed no detectable effect on total plate count. Beef hides in all packaging resulted in an increase in total microorganisms on day 4, 7, 14, and 21, respectively, compared with day 0 (P < 0.001). Bloom strength progressively decreased (P = 0.005) 48% from day 0 to day 7 and 72% by day 21, with no difference detected between treatments.

Conclusion: Neither vacuum packaging nor nitrogen flushing sufficiently preserve beef hides to allow for accumulation and marketing for gelatin production. Additional methods should be investigated to identify a process that allows for accumulation of hides.

Keywords: bloom strength, putrefaction, vacuum packaging

24 ALKALINE UNHAIRING AND PICKLING OF BOVINE HIDES FOR GELATIN EXTRACTION

A. Manzoor^1*, G. Allen¹, J. Brown¹, C. Brown¹, B. Winslow¹, A. Liuzzo¹, and J. M. Scheffler¹, ¹Animal Sciences, University of Florida, Gainesville, Florida, USA, *jmscheff@ufl.edu

Objectives: Hide as a byproduct of the meat industry is commonly utilized for leather production. However, supplying hides for leather processing is not economically viable for small-scale processors. Not only do small processors have difficulty marketing hides, but they also bear the cost of hide disposal. Bovine hide constitutes approximately 30% protein, and the inner corium layer is rich in collagen. Collagen is primarily used in the food, cosmetic, and pharmaceutical industries, and demand for collagen is increasing. Additionally, current lime unhairing methodologies take days to process and produce a waste stream with significant environmental concerns, so more environmentally friendly methodologies are desired. The objective of this trial was to evaluate the effect of an alkaline unhairing and pickling method on gelatin quality.

Materials and Methods: Raw bovine hides were cut into approximately 400-cm² patches. The hide was unhaired in 2M NaOH at a 1:1 (w/v) ratio of hide and solution for 4 h at room temperature. Thereafter, patches were rinsed thoroughly with water and pickled in a 2.25M HCl solution at 1:1 (w/v) ratio of hide and solution containing different NaCl concentrations (0%, 1.5%, and 2.5%) for 15 or 30 min under continuous stirring. Samples were washed with water and kept at 4°C overnight. For the control treatment, the hide was unhaired by soaking in aqueous lime solution for 3 d, and no acid pickling was done. Each treatment was conducted in 3 replicates. Gelatin extraction was performed in a water bath at 80°C for 75 min after cutting hide into approximately 1-cm strips. The obtained solution was filtered through cheesecloth followed by dialysis in distilled water for 48 h. Gelatin was then freeze dried for determination of yield, bloom strength, and HunterLab L, a, and b color. Statistics were analyzed using SAS JMP (SAS Institute Inc., Cary, NC). Dunnett’s test was used to determine difference from the lime control. Significance was determined at P < 0.05.

Results: Compared with lime control, only pickling with 0% salt for 30 min resulted in increased (P = 0.02) gelatin yield. No difference in bloom strength was detected between control and any combination of alkaline unhairing, salt concentration, and pickling time. All alkaline unhaired samples had lower (P < 0.018) L values and higher (P < 0.006) a values than the lime control. No salt and 1.5% pickle resulted in higher (P < 0.05) b values regardless of pickling time.

Conclusion: Using 2M NaOH for dehairing and pickling in 2.25M HCl across a range of salt concentrations (0%, 1.5%, and 2.5%) for 15 or 30 min produced gelatin of comparable bloom strength to conventional methods, albeit darker and redder in color. Further refinement of alkaline unhairing methodology may provide small processors with an option to add value to their beef hides.

Keywords: bloom strength, collagen, pickling

25 ULTRASONICATION OF MEAT ENHANCES THE ACTIVITY OF SEVERAL PROTEOLYTIC SYSTEMS INVOLVED IN POSTMORTEM PROTEOLYSIS AND TENDERIZATION

D. Dang^1*, C. D. Stafford¹, J. F. Buhler¹, M. J. Taylor¹, J. E. Shippen¹, K. J. Thornton², and S. K. Matarneh¹, ¹Department of Nutrition, Dietetics, and Food Science and ²Department of Animal, Dairy and Veterinary Sciences, Utah State University, Logan, Utah, USA, *ds.dang24@gmail.com

Objectives: Among the eating quality characteristics of cooked beef, tenderness is considered one of the most important factors dictating consumers’ overall satisfaction and future purchasing decisions. The development of meat tenderness has been mainly attributed to postmortem proteolysis that occurs during aging. However, the various postharvest factors that can influence proteolysis consequently pose a challenge for the meat industry in producing a consistently tender product. To combat this challenge, the meat industry utilized new technologies and strategies to improve the uniformity of tenderness across products. Power ultrasound is an innovative technology that offers an effective method of improving meat tenderness without negatively affecting other quality traits. At low frequency (20–100 kHz) and high intensity (<10 W/cm²), ultrasonication is capable of disrupting biological material on both a macro and micro scale through the generation of cavitating bubbles. Such an effect is considered favorable because it can enhance proteolysis by disrupting organelles, such as the sarcoplasmic reticulum and mitochondria, which would release cofactors (i.e., calcium and cytochrome c) that can activate the calpain and caspase proteolytic systems. To the best of our knowledge, no previous studies have provided a thorough investigation on the biochemical mechanisms through which power ultrasound enhances meat tenderness. We hypothesized that power ultrasonication is capable of improving tenderness in beef steaks by causing cellular disruption and subsequently releasing available activating factors of various proteolytic systems.

Materials and Methods: To test our hypothesis, postrigor (24 h postmortem) longissimus steaks (n = 8/animal) collected from 8 steers (∼24 mo old, 470 ± 11.3 kg live weight) were subjected to power ultrasonication (treatment) of 40 kHz and 12 W/cm² for 40 min at 4°C or no ultrasonication (control). Warner-Bratzler shear force values, proteolysis, free calcium concentration, pH, calpain-1 autolysis, and caspase-3 and cathepsin B activity were evaluated at 0, 24, 168, and 336 h post treatment. In addition, isolated mitochondria were collected at each timepoint in order to evaluate mitochondrial efficiency and respiration. Collected data were analyzed using a Student t multiple comparison test, with P ≤ 0.05 considered statistically significant.

Results: Our results showed that ultrasonicated steaks had lower (P < 0.05) Warner-Bratzler shear force values than controls at each timepoint. In conjunction with the increase in tenderness, increased (P < 0.05) troponin-T degradation at 24 h and desmin degradation at 168 and 336 h were observed in the treated steaks. Ultrasonicated steaks had greater (P < 0.05) calpain-1 autolysis immediately after treatment as well as greater (P < 0.05) free calcium concentration at 0, 24, 168, and 336 h. Additionally, an increase of caspase-3 and cathepsin B activity was observed at 0 and 168 h, respectively, in the ultrasonicated steaks. Evaluation of mitochondrial efficiency and respiration in the treated steaks indicated a significant decrease (P < 0.05) in respiratory capacity at 0 and 24 h.

Conclusion: Collectively, these results suggest that improvement in tenderness through ultrasonication is governed by a multitude of cellular mechanisms that involve the calpain, caspase, and cathepsin systems.

Keywords: mitochondria, postmortem proteolysis, ultrasonication

26 COLOR VARIATION OF PET TREATS GENERATED FROM BEEF PROCESSING COPRODUCTS

C. W. Starkey^1*, M. R. Presume¹, R. F. Soler¹, J. L. Sandoval¹, L. P. Avila¹, M. E. Chilenje¹, C. M. Odom¹, L. J. Garner¹, A. U. Morey¹, R. P. Mason², and E. K. Altom², ¹Poultry Science, Auburn University, Auburn, Alabama, USA; ²Animal Nutrition and Health, Balchem Corporation, New Hampton, New York, USA, *cstarkey@auburn.edu

Objectives: Beef processing generates coproducts such as liver and heart. Although these products possess a significant amount of protein and nutrients, they are often undervalued. Despite the low consumer acceptance for their own meals, beef liver (BL) and beef heart (BH) offer great potential for the development of pet treats, using ALGIN (sodium alginate and encapsulated calcium lactate) as a structure forming agent. Characteristics such as color are among the contributing factors to desirable organoleptic properties that drive consumers to purchase pet foods and treats. An experiment was designed to evaluate color variation (CV) of raw and dehydrated pet treats designed from BL and BH mixtures with ALGIN inclusion for 7 d post production.

Materials and Methods: Organ meats were ground and mixed to achieve the following 3 ratios: 25% BL:75% BH, 50% BL:50% BH, and 75% BL:25% BH. Subsamples of the 3 BL:BH mixtures were combined with 2 concentrations of ALGIN (0.5% of sodium alginate + 0.425% encapsulated calcium lactate; 1% of sodium alginate + 0.85% encapsulated calcium lactate) to produce 6 treatments. Each treatment was then extruded to generate 20-mm-thick slices, wrapped, and refrigerated at 3°C for 48 h. Squares (n = 10) of 38 × 38 mm were selected from each treatment for CV measurements on raw samples. For cooked sample analysis, raw treats were dehydrated at 93°C for 2.5 h. Raw and dehydrated pet treat CV (N = 10 replicate samples per treatment) was measured by the CIE L*, a*, b* color space using a Minolta colorimeter on the top cut surface after 0, 3, 5, and 7 d of storage. Data were analyzed using the GLIMMIX procedure of SAS (version 9.4, SAS Institute Inc., Cary, NC), and means were separated using PDIFF at P ≤ 0.05.

Results: Interactions were observed between organ meat proportions and ALGIN concentrations. Lightness of raw pet treats was not affected by ALGIN concentration on day 0 (P = 0.1469), day 3 (P = 0.2873), and day 7 (P = 1.000) but slightly increased with increasing ALGIN concentration on day 5 (P = 0.005). However, samples became darker as BL proportions increased on days 0, 3, 5, and 7 (P < 0.0001). BL and BH combinations did not affect redness of raw treats on day 0 (P = 0.1458) and day 7 (P = 0.1053), but redness decreased as BL proportions increased on day 3 (P = 0.001) and day 5 (P < 0.0001). Yellowness of raw pet foods increased as ALGIN concentration increased on day 0 (P < 0.0001), day 3 (P = 0.0002), day 5 (P = 0.0068), and day 7 (P = 0.0079). Yellowness decreased as BL proportions increased on days 0, 3, and 5 (P < 0.0001), but no difference was observed on day 7 (P = 0.100). Cooked samples were lighter when ALGIN concentration increased (P < 0.0001) but displayed darker appearances as BL proportions increased on day 0 (P = 0.0017), day 3 (P = 0.0007), and days 5 and 7 (P < 0.0001). Redness of dehydrated treats increased with increasing BL proportions (P < 0.0001). Yellowness of dehydrated samples increased as ALGIN concentration increased on day 3 (P = 0.0456) and days 5 and 7 (P < 0.0001). Yellowness was not affected by BL and BH combinations on day 0 (P = 0.1687) and day 7 (P = 0.0906) but increased with decreasing BH proportions on day 3 (P = 0.0158) and day 5 (P < 0.0001).

Conclusion: These data suggest that liver, which liquifies when ground, can be stabilized for use in product design through the inclusion of ALGIN. ALGIN inclusion may allow processors to increase the value of organ meats when directed to a pet food market.

Keywords: alginate, beef processing, color, coproducts, pet food

27 APPLICATION OF FOOD-GRADE COATINGS TO PREVENT MITE INFESTION IN AMERICAN COUNTRY CURED HAM PROCESSING

W. Shao^1*, Y. L. Campbell¹, X. Zhang¹, J. D. Hendrix¹, T. Phillips², and M. W. Schilling¹, ¹Department of Food Science, Nutrition and Health Promotion, Mississippi State University, Mississippi State, Mississippi, USA; ²Department of Entomology, Kansas State University, Manhattan, Kansas, USA, *ws525@msstate.edu

Objectives: Tyrophagus putrescentiae is a ubiquitous pest of stored food products that contain high percentages of fat and protein, including dry-cured hams. Methyl bromide effectively controls mites in stored food products but has been listed as an ozone-depleting substance since 1992, and only existing stocks can be utilized by the dry-cured ham industry. Chitosan (CH) is generally recognized as safe (GRAS) by the Food and Drug Administration and possesses potential efficacy to control mites. Therefore, the objective of this research was to evaluate whether CH-containing food-grade alternatives can be used to control mite infestation without affecting sensory attributes of dry-cured hams.

Materials and Methods: The food-grade coating treatments were prepared as follows: (a) 0.3% CH, (b) 0.6% CH, (c) 0.3% CH + 10% propylene glycol (PG), (d) 0.3% CH + 1% xanthan gum (XG), (e) 0.3% CH + 1% XG + 10% PG, (f) 0.3% CH + 1% carrageenan + 1% propylene glycol alginate (PGA), and (g) 0.3% CH + 1% carrageenan + 1% PGA + 10% PG. Each coating solution was coated on ham cubes (2.54 × 2.54 × 2.54 cm³, n = 5/treatment). Each coating solution was also infused in ham nets, and dry-cured ham cubes (2.54 × 2.54 × 2.54 cm³, n = 5/treatment) were wrapped in the ham nets. Twenty adult mites were inoculated onto the individual cubes that were stored in ventilated jars. The jars were then stored in an environmental chamber at 24°C and 75% relative humidity for 2 wk. After 2 wk of incubation, the number of mobile mites on each ham cube was counted. Difference from control tests were conducted on ham slices that were wrapped with nets infused with solutions which control mites (d, e, f, g) to evaluate their impact on the sensory attributes of the ham slice. A randomized complete block design with 3 replications was utilized to evaluate the efficacy of treatments in controlling mite infestations on dry-cured hams. When differences occurred (P < 0.05), Duncan’s new multiple range test was used to separate treatment means.

Results: When CH was mixed with XG (0.3% CH + 10% PG + 1% XG; and 0.3% CH + 1% XG), fewer mites (15.7 and 21.0 mites) were on the ham cubes (P < 0.05) in comparison with the control (211.2 mites) when the coating solution was infused in a net. Mite counts did not differ (P > 0.05) between 0.3% CH + 1% XG + 10% PG and 0.3% CH + 1% XG. This indicates that addition of CH can reduce the amount of PG that is needed from 15% (previous research) to 10% in current research. Results also indicate that CH enhance the efficacy of 1% XG to control mites because 1% XG alone reduced mite growth but did not control mites to the initial inoculation level from previous research. In conclusion, including CH in the coating may improve mite-controlling efficacy when combining with polysaccharides such as XG. Difference from control test results indicated that no sensory differences existed (P > 0.05) between CH-treated and untreated ham slices. On average, none of the CH-treated ham slices were rated above 2 on a 4-point scale in which 0 = no difference, 2 = moderate difference, and 4 = very large difference.

Conclusion: Addition of CH-coated nets helped control mite growth when used in conjunction with XG and PG. Therefore, these coating solutions may be usable as part of an integrated pest management plan for ham producers and scale up to control mites in their aging houses.

Keywords: chitosan, dry-cured ham, food-grade, ham mites

28 RESIDUAL NITRITE AS A BASELINE FOR AN AMINO ACID ALTERNATIVE CURING SYSTEM

K. M. Modrow^1* and W. N. Osburn¹, ¹Animal Science, Texas A&M University, College Station, Texas, USA, *kmmodrow2017@gmail.com

Objectives: The study objective was to assess the ability of L-arginine-HCL to generate residual nitrite (RNO₂) values comparable to sodium nitrite (NaNO₂)-treated beef, pork, and poultry samples.

Materials and Methods: Individual batches of ground beef and pork (80/20) and poultry (97/3) were mixed with 2% salt and 10% water (N = 9), and then split into 454-g batches. Each test batch was blended with Prague powder (6.25% NaNO₂) to achieve 120, 156, or 200 ppm sodium nitrite or 1,000, 2,000, 3,000, 4,000, or 5,000 ppm L-arginine with 547 ppm sodium erythorbate. After mixing (1 min), 25-g samples were extruded into two 50-mL centrifuge tubes. Sample tubes for a single species and ingredient (NaNO₂ N = 18; or L-arginine N = 30) were placed in a controlled water bath and cooked to either 55.6°C, 70.0°C, or 73.9°C. Samples were chilled (2°C) and then stored (2°C) for 7 d. RNO₂ (by UV/VIS spectrophotometry) and nitrosylation (determination of nitrosylhemochromagen [NO-H] formation) were analyzed after 7 d. The experiment was a factorial (3 NaNO₂ or 5 L-arginine concentrations [C] and 3 temperatures [T] with 2 samples per concentration) randomized complete block design. This resulted in 18 (NaNO₂) or 30 (L-arginine) sample tubes per cook batch for each species type, then replicated 3 times. Least-squares means were generated, and Tukey’s HSD was used with a predetermined significance of P < 0.05.

Results: For NaNO₂ beef and pork samples, a C × T (P < 0.05) interaction indicated that RNO₂ tended to decrease as temperature increased at each NaNO₂ concentration except for pork samples at 73.9°C. Poultry sample RNO₂ values increased as NaNO₂ concentration (P < 0.001) increased and decreased as temperature (P < 0.05) increased. L-arginine–treated beef sample RNO₂ values decreased as temperature (P < 0.0001) increased. As L-arginine concentration (P < 0.05) increased, pork samples exhibited a decrease in RNO₂ values except at 4,000 ppm. A C × T interaction (P < 0.0001) was observed for L-arginine poultry samples. As concentration increased, RNO₂ decreased at 55.6°C. At higher temperatures, 3,000 and 4,000 ppm L-arginine samples tended to have lower RNO₂ values. All L-arginine concentrations and endpoint temperatures for each species generated similar, but generally lower, RNO₂ values compared with NaNO₂ concentrations of 120, 156, and 200 ppm. NO-H values for nitrite-treated beef samples indicated that, as concentration increased, NO-H values decreased, whereas pork NO-H values tended to increase as endpoint temperature increased. A C × T interaction for poultry samples indicated that, as NaNO₂ concentration and temperature increased, NO-H values decreased, with higher NO-H values observed at lower endpoint temperatures (55.6°C). For L-arginine–treated beef, pork, and poultry samples, a C × T interaction indicated that, as concentration increased, NO-H values tended to increase at lower endpoint temperatures (55.6°C).

Conclusion: L-arginine concentrations of 1,000–4,000 (beef), 1,000–3,000 (pork), and 1,000–2,000 ppm (poultry) generated RNO₂ values comparable to NaNO₂-treated samples at concentrations of 120, 156, and 200 ppm. Higher endpoint temperatures tended to decrease RNO₂ levels. Using RNO₂ as a baseline, L-arginine concentration generated similar RNO₂ values compared with samples treated with 120, 156, or 200 ppm NaNO₂ at different endpoint temperatures. This indicates that L-arginine has potential to be an alternative curing system in processed meat products.

Keywords: cured meats, L-arginine, nitric oxide, sodium nitrite

29 MOISTURE UPTAKE IN BEEF JERKY AS IMPACTED BY RELATIVE HUMIDITY AND ASSOCIATED MOLDING

S. LaSuer^1*, G. McCoy¹, D. Unruh¹, S. Baker¹, and R. Ames¹, ¹Corbion, Corbion, Lenexa, Kansas, USA, *daniel.unruh@corbion.com

Objectives: This study evaluated the ability of beef jerky to uptake moisture from a high relative humidity (RH) environment and the ability of Verdad^® Powder N30 (cultured cane sugar [CCS]) to prevent mold growth in elevated RH conditions.

Materials and Methods: Experiment 1: Beef semitendinosus were denuded, sliced 1.3 cm thick, and further portioned to 1.2 cm × 1.6 cm pieces. Samples were vacuum tumbled with a brine containing 2.60% salt, 9.4% sugar, and 100 ppm ingoing sodium nitrite, targeting 17% extension. Samples were dried in a smokehouse using a stage cook schedule to a water activity (a_w) of 0.76. After reaching target a_w, samples were vacuum packaged, and cook yield, pH, a_w, and moisture were reported. Samples were placed into a sealed environment where the RH was modified using two-way moisture packets to maintain a target RH of 80% ± 3%, 70% ± 3%, or ambient (no two-way moisture packets). The RH was monitored throughout the study using a hygrometer, and the a_w was measured every 7 d for 28 d. A single replication was performed to monitor moisture uptake. Experiment 2: Samples were prepared similar to Experiment 1 using a formula using a brine containing 1.65% salt, 6.0% sugar, 100 ppm sodium nitrite, and a treatment consisting of a negative control (no antimicrobial), 0.5% CCS, or 0.75% CCS. Samples were dried in a smokehouse using a stage cook schedule to a target a_w of 0.81 ± 0.02. Finished samples from each treatment were assigned to either an inoculated on noninoculated group. Inoculated samples were spread with 1,000 spores per sample from a cocktail containing Penicillium roqueforti, Penicillium commune, Penicillium crustosum, Penicillium chrysogenum, and Aspergillus flavous. Both inoculated and noninoculated samples were placed into a sealed environment with 80% ± 3% RH controlled via two-way moisture packs. The RH was monitored throughout the study using a hygrometer, and samples were inspected for visible mold on a regular basis. Thirty pieces per treatment were monitored throughout the shelf life.

Results: Beef jerky samples stored at an elevated RH saw in increase in a_w, percentage moisture, and pH between day 0 and day 28 (see Table 1). Of the inoculated samples, mold was observed in control samples on day 13, and 100% of samples had visual mold growth by day 42. Noninoculated control samples began to mold on day 20; on day 72, 20% of control samples had visible mold. No visual mold growth was observed in samples formulated with CCS throughout the 72-d shelf life.

Conclusion: When beef jerky is exposed to an elevated RH environment, the a_w and moisture content increase, whereas pH remains relatively unaffected. The changes in product characteristics mean that shelf-stable beef jerky products can become susceptible to mold growth once opened. Verdad^® Powder N30 can prevent mold growth from occurring in beef jerky once the package is opened by consumers.

Keywords: beef, moisture, mold, relative humidity

30 EFFECT OF HIGH HYDROSTATIC PRESSURE AND VACUUM COOKING AT LOW TEMPERATURE ON THE TEXTURE AND COOKING LOSS OF LEAN BEEF PATTIES

R. Janardhanan^1*, F. C. Ibañez¹, P. C. Virseda¹, K. B. Insausti¹, N. Huerta-Leidenz², and M. J. Beriain¹, ¹ISFOOD, Public University of Navarra, Pamplona, Spain; ²Department of Animal and Food Sciences, Texas Tech University, Texas, USA, *rasmi.janardhanan@unavarra.es

Objectives: High hydrostatic pressure processing (HPP) induces changes in meat textural properties and can be used to develop new products or improve functional properties (Tewari et al., 1999). Sous-vide (SVCOOK) can enhance the tenderness of inherently tough meat cuts (Park et al., 2020). We hypothesized that the combined use of HPP and SVCOOK bring about beneficial effects on textural traits and reduce cooking losses of locally produced lean beef. Therefore, the present experiment examines the effects of combining HPP with SVCOOK on texture parameters and cooking loss of lean beef patties. Two cuts of the top sirloin cap portion of biceps femoris muscle were procured (3 d postmortem) from 3 bullocks (11 to 13 mo of age) of the local Pyrenean breed certified as Ternera de Navarra, a Protected Geographical Indication in Spain, Europe.

Materials and Methods: The research followed the official guidelines for the humane treatment, care, and handling of animals (Directive 2010/63/EU, Council Regulation 1099/2009). Proximate analysis of the raw meat was conducted. The meat was minced at 1,500 rpm for 30 s using a meat grinder and then pressed into 150-g patties using a patty press. The patties were HPP processed and subsequently subjected to SVCOOK. A central composite design of 20 runs was used with HPP pressure, HPP pressurization time, and SVCOOK temperature as independent variables (350–600 MPa, 5–15 min, 55°C–65°C); the center point was replicated 6 times. The texture profile analysis of the post-HPP SVCOOK patties was conducted using a TA-XT2i stable microsystems texture analyzer (Stable Micro Systems Ltd., Surrey, UK). Two-cycle 50% compression with a 30 kg load cell was used for the tests. Six consecutive readings were reported (Gómez et al., 2018). Texture profile analysis parameters such as cohesiveness, springiness, hardness, chewiness, resilience, and adhesiveness were measured. The cooking loss of the samples was calculated (Murphy et al., 1975).

Results: Moisture, protein, ash, and pH values for the raw meat samples were 75.7%, 21.6%, 1.2%, and 5.6 units, respectively. The fat content was low (1.3%), an “extra-lean” beef according to conventional claims for nutrition labeling (USDA, 2019). Significant modification in the texture values and cooking loss was observed in the treated meat patties (P < 0.05). The cohesiveness exhibited a linear relationship with HPP pressure. The increase in HPP pressure and SVCOOK temperature elevated the springiness, hardness, chewiness, and resilience, whereas an increase in HPP pressurization time reduced the samples’ chewiness. The rise in SVCOOK temperature increased the adhesiveness of the treated patties. It was noted that cooking loss increased with rising HPP pressure, HPP pressurization time, and SVCOOK temperature. Optimum processing parameters based on the lowest hardness and cooking loss were HPP treatment at 350 MPa for 10 min and subsequent SVCOOK at 55°C.

Conclusion: The recommended treatment with HPP + SVCOOK optimized the processing conditions. These findings extend the possibilities for preparing very lean beef patties from biceps femoris and suggest innovative product lines for the local agro-food industries using the Protected Geographical Indication–Ternera de Navarra low-fat meat products.

Keywords: high hydrostatic pressure, lean beef

31 RETAIL LIGHTING AND POSTMORTEM AGING IMPACT THE FLAVOR COMPOUNDS OF VACUUM-PACKAGED BEEF STEAKS

S. N. Barker^1*, J. F. Legako¹, J. C. Brooks¹, and D. R. Woerner¹, ¹Animal and Food Science, Texas Tech University, Lubbock, Texas, USA, *sam.barker@ttu.edu

Objectives: The objective of this study was to evaluate the volatile flavor compounds produced by individually vacuum-packaged beef steaks displayed under light-emitting diode (LED) or fluorescent (FLUR) light sources.

Materials and Methods: USDA Low Choice paired beef top sirloin butts, striploins, and tenderloins (n = 32) were collected at a commercial beef processing facility. Subprimals were aged for 7 d postmortem in the absence of light. Subprimals were fabricated into 2.54-cm-thick steaks representing the gluteus medius (GM), longissimus lumborum (LL), and psoas major (PM). Steaks were packaged in rollstock vacuum packaging and aged for an additional 7 d before being randomly assigned to a lighting display of either FLUR or LED for 0, 2, 6, or 10 d. Following the assigned aging periods, steaks were frozen at −20°C until further analysis. Gas chromatography–mass spectrometry was used to analyze 56 compounds associated with cooked beef flavor. Data were analyzed as a split-split plot with subprimal serving as the whole plot, lighting as the sub-plot, and days of age as the sub-sub plot. Peak cooked temperatures and cook loss percentages were used as covariates.

Results: Lighting type and display duration interacted (P ≤ 0.043), showing an increase (P < 0.05) in ethyl benzene as display duration increased, with LED lighting exhibiting the highest concentration at day 10. Lipid-derived volatile compounds, 1-octanol, octanal, nonanoic acid, and tetradecane were impacted the greatest by the interaction between lighting type and muscle type (P ≤ 0.046), showing greater concentrations in LL steaks stored under LED lighting. Lipid oxidation and Maillard reaction derived compounds were also most effected by the interaction between muscle type and display duration (P ≤ 0.049). Lipid-derived compounds, including ethanol and butanal, also increased (P ≤ 0.049), showing an interaction for all muscle types as display duration increased. Strecker aldehyde concentration, specifically phenylacetaldehyde, also increased (P < 0.05) in all muscles over the 10-d display duration. However, 2-methylbutanal and benzaldehyde only increased (P < 0.05) in the GM over the display duration. Display duration as a main effect showed an increase (P < 0.05) in carboxylic acids and 2-propanone by day 10. Strecker aldehyde concentrations were also greater (P < 0.05) by day 10. Muscle type as a main effect impacted (P ≤ 0.019) lipid-derived volatiles, including aldehydes, which showed greater (P < 0.05) concentrations in GM and LL steaks compared with PM steaks. Furthermore, sulfur-containing compounds, dimethyl sulfide and methanethiol, showed the greatest (P < 0.05) concentration in GM steaks than in LL and PM steaks. Finally, lighting type as a main effect impacted (P = 0.023) the Strecker aldehyde 3-methylbutanal, showing much greater (P < 0.05) concentrations under FLUR lighting than under LED lighting.

Conclusion: These results suggest that the impacts of muscle type and duration of display were greater on the production of volatile compounds than lighting type when analyzing vacuum rollstock packaged beef steaks. Nonetheless, lipid oxidation derived compounds were greater in LED displayed products. However, further research may be done to better understand the impact of lighting displays on flavor production in comparison with volatile flavor compound production.

Keywords: aging, gas chromatography, lighting, retail display, volatile flavor compounds

32 STRUCTURALLY RELATED PHENOLIC ACIDS DIFFERENTIALLY AFFECT THE GELLING BEHAVIOR OF OXIDATIVELY STRESSED PORK MYOFIBRILLAR PROTEIN

A. Guo¹ and Y. L. Xiong^1*, ¹Animal and Food Sciences, University of Kentucky, Lexington, Kentucky, USA, ylxiong@uky.edu

Objectives: Polyphenol-rich spices and seasonings are commonly used in sausage products to enhance product flavor and oxidative stability. Previous research has shown that released phenolic compounds could interact with myofibrillar protein (MP) extracted by salt in meat processing to change the protein functionality. The objective of the present study was to compare the effects of 6 structurally related phenolic acids, i.e., gallic acid (GA), syringic acid (SA), coumaric acid (CMA), caffeic acid (CFA), ferulic acid (FA), and chlorogenic acid (CA), on the gelling properties of MP prepared from pork muscle.

Materials and Methods: Phenolic acids (60 μmol/g protein) were mixed with 2% (w/v) MP at pH 6.2 and then exposed to a hydroxyl radical-oxidizing environment generated with 50 μg glucose and 8 μg glucose oxidase (per milligram of protein) in the presence of 10 μM FeSO₄ at refrigerator temperature for up to 8 h. Changes in protein sidechain groups and derivatives (sulfhydryls, free amines, and carbonyls), conformation (tryptophan fluorescence), rheological properties, and gelling potential were analyzed. The phenol–MP interaction experiments were conducted with 3 independent trials (n = 3) on different days, each with a new batch of isolated MP. Data were subjective to analysis of variance, and significant differences between means were identified with Tukey’s test at P < 0.05.

Results: Of the 6 phenolic compounds, the smallest compound, GA, caused significant loss of sulfhydryls and free amines (by 7% and 26%, respectively, P < 0.05). Other phenols except CA exhibited no effect on the amino acid side chain groups but all quenched tryptophan fluorescence, suggesting protein conformational changes. The largest molecule, CA, was the most effective, which deceased the fluorescence intensity 38% and shifted λ_max from 338 nm to 350 nm. During thermal gelation, the GA-modified MP displayed the strongest interpeptide cross-linking. The elasticity (G') and breaking strength of the MP gels were markedly enhanced by the addition of phenolic acids (P < 0.05), with the final G' value ranked in the order of GA > CA > FA > CMA > SA > CFA > control. The rate of protein thermal aggregation was linked to physicochemical modifications of MP, which affected its gelling potential.

Conclusion: Smaller phenolic acids with less structural hinderance and more reducing potential promoted protein cross-linking and gel matrix formation, whereas larger molecules with more substituent groups enhanced protein unfolding and aggregation rate. The findings suggest that variations in phenolic acid composition are a possible cause for texture inconsistency observed among meat products incorporated with different spices.

Keywords: gelation, myofibrillar protein, oxidation, polyphenols, pork

33 EVALUATION OF AN AMINO ACID BASED ALTERNATIVE CURING SYSTEM ON THE PHYSIOCHEMICAL AND SHELF LIFE ATTRIBUTES OF BEEF FRANKFURTERS

S. E. Bludau^1*, K. M. Modrow¹, and W. N. Osburn¹, ¹Animal Science, Texas A&M University, College Station, Texas, USA, *sarahbludau26@gmail.com

Objectives: The objective of this study was to evaluate the efficacy of an amino acid–based “no added sodium nitrite” alternative curing system compared with a conventional curing system (direct addition of sodium nitrite).

Materials and Methods: Beef (90/10) was used to create frankfurter emulsions (∼13 kg) containing salt (1.8%), sodium tripolyphosphate (3,500 ppm), seasonings, added water (10%) containing either 156 ppm sodium nitrite (6.25% Prague powder, conventional curing) or one of 3 concentrations of the semi-essential amino acid L-arginine (3,000, 4,000, and 5,000 ppm). Frankfurter emulsions were stuffed into 26 mm cellulosic casings thermally processed using a standard frankfurter schedule until an internal temperature of 72.2°C was reached and then chilled (4.4°C), peeled, and vacuum packaged. The frankfurters were stored under refrigeration (2°C) until analyzed at 1, 14, 28, and 56 d post manufacture and were evaluated for proximate composition, pH, water activity, residual nitrite, color (internal and external), lipid oxidation, aerobic plate counts, and volatile compounds. The study was designed as a factorial randomized complete block design with 3 replications. Data were analyzed using the SAS JMP Pro 15 software (SAS Institute Inc., Cary, NC). Least-squares means and analysis of variance with P = 0.05 were used to determine significant main effects. Significant differences were determined by Tukey’s HSD (P < 0.05).

Results: A concentration × day interaction (P < 0.001) was observed for residual nitrite values. Treatment frankfurters were lower in residual nitrite than the nitrite control across all L-arginine concentrations at day 1 and 7 of refrigerated storage. From day 14 to day 56 of storage, residual nitrite values for L-arginine–treated frankfurters were similar (day 14) or slightly higher (days 28 and 56). A concentration × day interaction (P < 0.05) was also observed for lipid oxidation as indicated by 2-thiobarbituric reactive substances (TBARS) values. Treatment frankfurters tended to be higher than the control throughout the 56-d storage period, but TBARS value differences tended to decrease as the length of storage increased. All treatment and control frankfurters exhibited TBARS values less than 1.0 at day 56. A concentration × day effect was observed for total aerobic plate counts. Microbial growth was similar for treatment and control frankfurters through day 28 of refrigerated storage. On day 56, treatment frankfurters tended to be 0.5 to 1.0 log CFU/g higher than the sodium nitrite control. Internal product color means were also influenced by a concentration × day interaction. L* and b* values were not different between treatment and control frankfurters through 56 d of storage. However, internal a* values were approximately 50% less intense than the sodium nitrite control frankfurters for all storage days.

Conclusion: The results from this study indicate that L-arginine can be used as a substrate to activate the nitric oxide synthase system to generate residual nitrite and nitric oxide in a similar fashion to conventionally cured (sodium nitrite) beef frankfurters. The potential exists for L-arginine to be used to generate sodium nitrite as an alternative curing system for processed meat products.

Keywords: alternative, amino acids, cured meats, sodium nitrite

34 MUSCLE-SPECIFIC IMPACTS OF FRESH BEEF TUMBLING ON MEAT QUALITY, PALATABILITY, AND PROTEOLYTIC ATTRIBUTES OF SIRLOIN MUSCLES

J. R. Tuell^1*, M. J. Nondorf¹, M. Abdelhaseib¹, D. Setyabrata¹, J. Legako², and Y. H. B. Kim¹, ¹Animal Sciences, Purdue University, West Lafayette, Indiana, USA; ²Animal and Food Sciences, Texas Tech University, Lubbock, Texas, USA, *tuell@purdue.edu

Objectives: Muscles originating from the sirloin area of beef carcasses often exhibit intermediate tenderness. Fresh beef tumbling (without inclusion of brine solution) has recently been demonstrated to improve tenderness and possibly other eating quality attributes of beef loins. No previous studies have evaluated the impacts of fresh beef tumbling on the meat quality, palatability, and proteolytic attributes of beef sirloin muscles. The objective of this study was to evaluate the effects of fresh beef tumbling with further postmortem aging on these traits in 3 sirloin muscles.

Materials and Methods: M. gluteus medius (GM), biceps femoris (BF), and tensor fasciae latae (TFL) were obtained at 5 d postmortem from both sides of beef carcasses (n = 16; USDA Low Choice). Muscles were distributed among the tumbled (120 min of tumbling [T120]) and non-tumbled control (T0) groups. Afterward, muscles were transversely sectioned and allocated among further postmortem aging treatments (0 d or 10 d). Meat quality was assessed by water-holding ability and Warner-Bratzler shear force (WBSF) values. Palatability attributes such as tenderness (myofibrillar, connective tissue, overall), juiciness (overall), and flavor (beef flavor, liver-like, oxidized, and others) were determined by trained sensory panelists (n = 8) at Texas Tech University. Attributes such as degradation of troponin T and desmin, collagen content and solubility, and myofibril fragmentation index were evaluated. Data were analyzed in a balanced complete block design with a factorial arrangement of tumbling and aging treatments using the PROC GLIMMIX procedure of SAS (version 9.4, SAS Institute Inc., Cary, NC).

Results: Fresh beef tumbling induced higher moisture losses in all 3 muscles for purge loss at 0 d and cook loss (P < 0.05) but not purge loss at 10 d and thaw loss (P > 0.05). Lower WBSF values were found in the T120 group for GM and TFL muscles (P < 0.05) but not BF muscle (P > 0.05). However, BF muscle from the T120 group at 10 d further aging had less intact troponin T compared with other treatment groups within BF muscle (P < 0.05). Higher myofibril fragmentation index was found in the T120 group for all muscles compared with T0 controls (P < 0.05). In general, collagen content and solubility were not affected by tumbling and aging treatments (P > 0.05). Trained panelists found T120 GM muscles to have higher myofibrillar tenderness, but a slight oxidized flavor, compared with T0 (P < 0.05). The T120 treatment decreased juiciness of BF muscle (P < 0.05), whereas no other sensory attributes were affected (P > 0.05). Higher liver-like flavor was observed in T120 TFL muscle compared with T0 (P < 0.05).

Conclusion: The results of this study suggest that the effects of fresh beef tumbling on quality, palatability, and proteolysis would be muscle specific. Effects of tumbling were most apparent in GM muscle, for which lower WBSF values and higher myofibrillar tenderness were observed. Although WBSF and sensory tenderness of BF muscle were not impacted in the present study, there was evidence of enhanced proteolysis through tumbling. Accordingly, optimization of the process regarding durations of tumbling and aging would be necessary to improve the quality of individual muscles from the beef sirloin region. However, because some slight detriments to trained panel sensory flavor scores were observed, further research into the impacts of fresh beef tumbling on oxidative stability would be warranted.

Keywords: beef quality, instrumental tenderness, meat tumbling, postmortem proteolysis, trained sensory panel

35 MITOCHONDRIAL CALCIUM BUFFERING LIMITS POSTMORTEM PROTEOLYSIS IN AN IN VITRO MODEL

C. Stafford^1*, J. F. Buhler¹, D. S. Dang¹, M. J. Taylor¹, K. J. Thornton², and S. K. Matarneh¹, ¹Department of Nutrition, Dietetics and Food Sciences and ²Department of Animal, Dairy and Veterinary Sciences, Utah State University, Logan, Utah, USA, *chandler.stafford1@gmail.com

Objectives: Among all meat quality attributes, tenderness is arguably the most important characteristic, determining overall customer satisfaction and future intentions to repeat purchase. Despite being influenced by several intrinsic and extrinsic factors, it is widely regarded that postmortem proteolytic degradation of muscle proteins (proteolysis) is the main contributor to end-product tenderness. Proteolysis is a process that relies mainly on the calcium-dependent protease calpain-1. Although a great deal of effort has been devoted to understanding factors controlling calpain-1 activity, undesirable variation in meat tenderness still exists, suggesting that the mechanisms and modulators of calpain-1 activity are not fully understood. Mitochondria are often disregarded in their involvement within postmortem proteolysis; however, recent research suggests that these organelles can sequester and store large amounts of calcium during the postmortem period. Hence, this research aims to investigate mitochondrial calcium buffering capacity and its influence on modulating calpain-1 activation during the postmortem period. Using an in vitro model, we hypothesized that mitochondria may delay the activation calpain-1 by sequestering a proportion of the available calcium.

Materials and Methods: To test this hypothesis, we conducted 2 separate experiments. In the first experiment, mitochondrial calcium buffering capacity was evaluated in a mannitol-sucrose buffer containing different concentrations of mitochondrial protein (0, 0.5, or 2.0 mg/mL) and calcium (0, 50, or 100 μM). After 15 min of incubation, free calcium concentration was determined using an ion selective calcium electrode. In the second experiment, we sought to simulate postmortem conditions within muscle tissue for the purpose of showing mitochondrial impact on proteolysis. The amounts of 0, 0.5, or 2.0 mg/mL of isolated mitochondrial protein was incorporated into an in vitro system containing homogenized prerigor bovine longissimus muscle in a reaction buffer containing all of the metabolites and cofactors required for postmortem metabolism. Calpain-1 autolysis and proteolysis were evaluated at 0, 120, and 240 min. Data were then analyzed using a Tukey-Kramer multiple comparison test, with P ≤ 0.05 considered statistically significant.

Results: Our results showed a significant decrease in calcium concentrations (P < 0.0001) preceding the addition of mitochondrial protein. Furthermore, treatment of mitochondria resulted in a significant reduction (P < 0.05) in the degradation of troponin-T at 120 and 240 min. A trend was also observed for calpain-1 autolysis in which less autolysis occurred with increasing mitochondria concentration.

Conclusion: The current results suggest that mitochondria, in their capacity to buffer calcium in an in vitro system, has the propensity to limit postmortem proteolysis. Collectively, this research will further our understanding of biochemical processes demonstrated in postmortem proteolysis and provide evidence that mitochondria can influence meat tenderness.

Keywords: calcium buffering, mitochondria, postmortem proteolysis, tenderness

36 TRAINED SENSORY PANEL EVALUATION OF THE IMPACT OF BONE-IN VS. BONELESS CUTS ON BEEF PALATABILITY

K. J. Farmer^1*, E. S. Beyer¹, S. G. Davis¹, K. M. Harr¹, M. D. Chao¹, J. L. Vipham¹, M. D. Zumbaugh¹, and T. G. O’Quinn¹, ¹Animal Sciences and Industry, Kansas State University, Manhattan, Kansas, USA, *kjfarmer@ksu.edu

Objectives: The objective of this study was to determine the palatability attributes of beef cuts (strip loin, tenderloin, and ribeye) of varying bone states and quality grades.

Materials and Methods: Left and right sides of 12 beef carcasses representing USDA Choice (upper 2/3) and USDA Select quality grades were selected by trained Kansas State University (KSU) personnel at a commercial abattoir in the Midwest. Paired (n = 12 pairs; 24 total/cut/grade) beef short loins and export ribs/boneless ribeye rolls were collected and transported to the KSU Meat Laboratory. Short loins were fabricated into either a boneless strip loin with a corresponding bone-in tenderloin or a bone-in strip loin with a boneless tenderloin at 3 d postmortem. In total, product was aged for 28 d and then fabricated into 2.5-cm-thick steaks and frozen. Steaks designated for trained sensory analysis were thawed at 2°C to 4°C for 24 h prior to cooking. Weight was measured on the raw and cooked samples as well as the edible lean and inedible bone and fat portions of the steaks to calculate cook loss and yield. Steaks were cooked to a peak temperature of 71°C on clamshell-style grills. A total of 18 sensory panels were conducted at the KSU Meat Science Sensory Lab. Panelists ranked the samples on a 100-point continuous line scale with descriptive anchors at 0, 50, and 100. A sensory score of 0 corresponded to extremely dry/tough/none/extremely bland/no off-flavor; a score of 50 corresponded to neither dry nor juicy/neither tough nor tender; and a score of 100 corresponded to extremely juicy/tender/abundant/extremely intense. Data were analyzed as a split-plot design with a whole plot factor of quality grade and subplot factors of muscle and bone state.

Results: Overall, bone status had a minimal impact on palatability traits. However, bone-in tenderloins and bone-in ribeyes were rated more flavorful (P < 0.05) than boneless cuts from the same muscle. There were no beef flavor intensity differences observed for bone-in and boneless strip steaks. Bone state had no effect (P > 0.05) on initial juiciness, myofibrillar tenderness, overall tenderness, or Warner-Bratzler shear force (WBSF) for any cut. Bone-in strip loin samples were rated juicier (P < 0.05) than tenderloins and boneless ribeye samples. Furthermore, tenderloin samples were ranked higher (P < 0.05) for myofibrillar and overall tenderness than strip loin and ribeye steaks, which were which were rated similar (P > 0.05) by trained panelists. Moreover, there was no difference (P > 0.05) in the WBSF values for strips and ribeyes, with tenderloin samples having the lowest (P < 0.05) average peak force. Lastly, USDA Choice samples were rated higher (P < 0.05) for all palatability traits and had lower WBSF values than Select samples.

Conclusion: The differences observed within palatability traits show that bone-in and boneless cuts of the same muscle rate similar regardless of bone state. This provides evidence that a similar overall eating experience could be derived from a bone-in or boneless steak from the same cut and grade.

Keywords: beef, bone-in, boneless, tenderloin, trained sensory analysis

37 DESCRIPTIVE AND CONSUMER SENSORY CHARACTERIZATION OF BEEF STRIP LOINS WET AGED IN DIFFERENT TEMPERATURE ENVIRONMENTS AND DURATION

M. S. Hernandez^1*, D. R. Woerner¹, J. C. Brooks¹, and J. F. Legako¹, ¹Animal and Food Science, Texas Tech University, Lubbock, Texas, USA, *sebastian.hernandez@ttu.edu

Objectives: The objective of this study was to evaluate the influence of beef wet aging temperature and duration on subjective and objective measures of beef palatability.

Materials and Methods: Paired USDA Choice strip loins (n = 60) were collected from a commercial beef processing facility. Each carcass was assigned to a storage temperature (−2°C, 0°C, 4°C). Strip loins were portioned into half loins and assigned to an aging duration (14 d, 28 d, 42 d, 56 d). Loins were aged in commercial upright refrigerators. After aging, loins were fabricated into 2.54-cm steaks and assigned to either slice shear force, descriptive sensory analysis, or consumer sensory analysis. Steaks were cooked to reach an internal temperature of 71°C. Untrained consumers (n = 200) evaluated 7 samples for flavor, juiciness, tenderness, and overall liking using a 100-point line scale in which 0 = extremely tough/dry/bland/dislike and 100 = extremely tender, juicy, intense, like. Trained sensory panelists evaluated 16 beef flavor and texture attributes using a 100-point line scale in which 0 = extremely tough/dry/not detectable and 100 = extremely tender/juicy/intense. All sensory data were collected using digital surveys on electronic tablets. Data were analyzed as a split-plot wherein loin portion served as the whole plot and aging duration served as the subplot. An alpha of P ≤ 0.05 was used. Principal component analysis was conducted to further understand relationships between consumer and descriptive sensory scores.

Results: No interaction was observed for slice shear force values (P > 0.05). Loins aged in 4°C environments produced more tender steaks compared with −2°C and 0°C (P = 0.002). Steaks aged for 42 and 56 d were the most tender steaks (P < 0.001). Steaks aged for 14 d were the toughest, and steaks aged 28 d were intermediary (P < 0.001). For descriptive sensory analysis, an interaction was observed for beef identity, bloody/serum, fat-like, liver-like, bitter, sour, and musty/earthy (P < 0.05). Loins aged for 56 d at 4°C were the most intense for liver-like, sour, and musty/earthy notes compared with all other treatments (P < 0.05). Umami, metallic, salty, oxidized, and overall tenderness were impacted by aging duration (P < 0.05). Steaks from loins aged for 56 d had the lowest umami and salty intensity compared with all other aging durations (P ≤ 0.008). For consumer sensory analysis, an interaction was observed for juiciness, tenderness, and overall liking (P < 0.05). Flavor liking was not impacted by storage temperature, aging duration, or their interaction (P > 0.05). Steaks from loins aged for 14 d at −2°C were the rated the least for juiciness, tenderness, and overall liking (P < 0.05). Extended aged steaks (42 and 56 d) were rated the most tender by consumers regardless of storage temperature (P < 0.001). Principal component analysis was conducted to visualize relationships between treatments and sensory attributes. Factor 1 and Factor 2 explained 43.17% and 23.49% of the variation, respectively. Off-flavors (sour, oxidized, liver-like) clustered with loins aged for 42 or 56 d at 4°C. Both −2°C and 0°C treatments were associated with positive flavor attributes (Beef ID, fat-like, umami). Loins aged for 28 d at 4°C were closely related to all consumer liking attributes.

Conclusion: Extended aging and increased storage temperatures improved tenderness. Off-flavor intensity increased during extended aging but was dependent on storage temperature.

Keywords: flavor, sensory, temperature, tenderness, wet aging

38 INHIBITION OF PYRUVATE DEHYDROGENASE ACCELERATES ANAEROBIC GLYCOLYSIS IN AN IN VITRO MODEL

M. J. Taylor^1*, J. F. Buhler¹, C. D. Stafford¹, D. S. Dang¹, S. W. El-Kadi², D. E. Gerrard², and S. K. Matarneh¹, ¹Department of Nutrition, Dietetics, and Food Sciences, Utah State University, Logan, Utah, USA; ²Department of Animal and Poultry Sciences, Virginia Polytechnic Institute and State University, Blacksburg, Virginia, USA, *kenzietaylor4.mt@gmail.com

Objectives: The rate of postmortem pH decline is one of the most important factors involved in the development of meat quality attributes. Normally, pH gradually declines from 7.2 in living tissue to an ultimate value of approximately 5.6. This “normal” pH decline pattern is associated with most desirable meat quality attributes, whereas rapid pH decline is the immediate reason for pale, soft, and exudative meat defect. The decline in postmortem muscle pH is driven by postmortem anaerobic metabolism, where the rate of pH decline is a reflective of the intensity of metabolism. However, the biochemical mechanisms controlling this metabolically complex event remain rather unclear. While anaerobic glycolysis is, in fact, the dominant pathway postmortem, recent studies suggest that mitochondria can influence postmortem metabolism by competing with lactate dehydrogenase for pyruvate. Thus, the ability of mitochondria to metabolize pyruvate may reduce the pyruvate pool available for anaerobic glycolysis and, subsequently, the rate of pH decline. Therefore, the objective of this study was to elucidate the influence that the mitochondria have on the rate of postmortem pH decline. We hypothesized that inhibition of pyruvate dehydrogenase (PDH) and pyruvate carboxylase (PC) provides more substrate for anaerobic glycolysis, thereby increasing the rate of pH decline.

Materials and Methods: To test this hypothesis, we utilized CPI-613 and Avidin, which are known inhibitors of PDH and PC, respectively, in an in vitro system that is intended to mimic postmortem metabolism. Prerigor porcine longissimus muscle samples (n = 8) were collected immediately after harvest, powdered under liquid nitrogen, and homogenized in a reaction buffer containing all the constituents required for postmortem metabolism to occur. Four treatments were tested: control, CPI-613 (400 μM), Avidin (1.5 U/mL), and CPI-613 + Avidin. In a follow-up experiment, universally labeled glucose tracer ([¹³C₆] glucose) along with CPI-613 and Avidin were incorporated into the in vitro system to precisely track the fates of pyruvate using gas chromatography–mass spectrometry and ¹³C-mass isotopomer distribution analyses. Collected data were analyzed using a Tukey-Kramer multiple comparison test, with P ≤ 0.05 considered statistically significant.

Results: Our results showed that samples treated with CPI-613 (with or without Avidin) had lower pH (P < 0.05) and greater lactate and glucose-6-phosphate accumulation and glycogen degradation (P < 0.05) at 60, 120, and 240 min compared with control. No treatment effect was observed in PC inhibited samples with Avidin. The results from the follow-up experiment indicated lower enrichment of tricarboxylic acid cycle intermediates (alpha-ketoglutarate, succinate, and malate; P < 0.05) in CPI-613 + Avidin treated samples compared with control.

Conclusion: Collectively, our data show that inhibition of PDH increases glycolytic flux and decreases the enrichment of mitochondrial metabolites in an in vitro model, which suggests that mitochondria may be involved regulating postmortem glycolysis.

Keywords: mitochondria, pH decline, postmortem metabolism

39 INFLUENCE OF POSTMORTEM AGING AND STORAGE CONDITIONS ON TENDERNESS OF STRIPLOIN STEAKS FROM GRASS- AND GRAIN-FINSIHED BISON BULLS

L. M. Hite^1*, C. J. Newton¹, J. R. Mattheis¹, J. K. Grubbs¹, K. R. Underwood¹, C. Kruse², and A. D. Blair¹, ¹Animal Science, South Dakota State University, Brookings, South Dakota, USA; ²Turner Enterprises, Inc., Bozeman, Montana, USA, *lydia.hite@sdstate.edu

Objectives: The objectives of this study were to 1) compare the influence of postmortem aging on tenderness of striploin steaks from grain- and grass-finished bison bulls and 2) compare the influence of frozen storage on tenderness of striploin steaks from grain- and grass-finished bison bulls.

Materials and Methods: Bison bulls were randomly assigned to 2 finishing treatments: grain-finished (n = 30, backgrounded on pasture and finished for 130 d with ad libitum access to grass hay, alfalfa, whole corn prior to slaughter) or grass-finished (n = 30, remained on pasture until slaughter). Bulls were slaughtered at approximately 30 mo of age. Striploins were collected from both sides of each carcass and fabricated into 2.54-cm steaks. One steak was removed from the right striploin, vacuum packaged, and stored fresh for 14 d at 4°C. Four steaks fabricated from the left striploin were aged for 4, 7, 14, or 21 d, vacuum packaged, and frozen (−20°C) for approximately 5 mo. Warner-Bratzler shear force (WBSF) was utilized to determine objective tenderness. Frozen steaks were thawed at 4°C for 24 h before cooking and all steaks were weighed prior to cooking to an internal temperature of 71°C. After cooking, all steaks were cooled to room temperature (20°C) and reweighed to determine cook loss. Five to six 1.27-cm cores were removed from each steak and sheared once perpendicular to the muscle fiber orientation, and peak force was recorded. An average shear force value was then calculated for each steak. For Objective 1, shear force and cook loss data were analyzed as repeated measures using the compound symmetry covariance structure in the MIXED procedure of SAS (SAS Institute Inc., Cary, NC) for effects of finishing treatment, aging, and their interaction with peak temperature included as a covariate. For Objective 2, shear force and cook loss were analyzed for the effects of storage treatment, finishing treatment, and their interaction using the MIXED procedure of SAS.

Results: A finishing treatment by aging day interaction was observed for WBSF (P = 0.0047). Steaks from the grain-finished treatment became more tender (P < 0.0001) as aging time increased from day 4 to day 14, whereas WBSF of steaks from grass-finished bulls did not change (P > 0.05) from day 4 to day 14. Steaks from grass-finished bulls were more tender (P < 0.05) than grain-finished at days 4 and 7, but treatments were similar (P > 0.05) at days 14 and 21. Steaks from grass-finished bison bulls had increased cook loss (P < 0.0001) compared with steaks from grain-finished bison bulls; no effect of aging day or treatment by aging day interaction was observed for cook loss (P > 0.05). No storage treatment by finishing treatment interaction (P > 0.05) was observed for WBSF or cook loss. Frozen storage improved tenderness (P < 0.0001) of 14-d aged bison steaks compared with fresh storage but did not influence cook loss (P > 0.05).

Conclusion: Collectively, these data indicate that grass- and grain-finished bison bulls respond differently to postmortem aging, with grass-finished bulls producing steaks that are more tender earlier in the aging period but exhibiting increased cook loss compared with steaks from grain-finished bulls. Additionally, freezing steaks from bison bulls resulted in improved tenderness compared with fresh storage without impacting cook loss.

Keywords: bison, frozen storage, grain finished, grass finished, tenderness

40 EFFECTS OF INCREASED PORK HOT CARCASS WEIGHTS ON BIOCHEMICAL FACTORS IMPACTING TENDERNESS

K. J. Farmer^1*, E. A. Rice¹, A. B. Lerner¹, A. A. Welter¹, D. L. Boyle², M. D. Chao¹, J. L. Vipham¹, M. D. Zumbaugh¹, and T. G. O’Quinn¹, ¹Animal Sciences and Industry and ²Biology, Kansas State University, Manhattan, Kansas, USA, *kjfarmer@ksu.edu

Objectives: A previous study by Rice et al. (2019) observed improved tenderness ratings as hot carcass weight increased for both consumer and trained sensory panelists. Therefore, the objective of this study was to investigate potential causative biochemical factors for the improved tenderness of heavier pork carcasses.

Materials and Methods: Details regarding the swine production procedures and loin fabrication for this study are described in detail by Lerner et al. (2020) and Rice et at. (2019). In brief, market hogs in this study were intentionally fed to heavier live weights that exceeded industry standards. At harvest, carcasses were assigned to one of 4 hot carcass weight groups. Carcasses were categorized as light (LT; under 111.8 kg), medium light (MLT; 111.8 to 119.1 kg), medium heavy (MHVY; 119.1 to 124.4 kg), or heavy (HVY; greater than 124.4 kg). A sub-sample of chops (N = 80) representing each of the weight treatments was utilized in this study. Sarcomere length of powdered samples was determined by phase-contrast microscopy. Thirty sarcomeres were measured and analyzed for each sample using ImageJ. Total collagen content was determined by measuring the hydroxyproline content in each sample, assuming that 14% of collagen is hydroxyproline by weight. Finally, immunoblotting was used to determine proteolysis of Troponin-T. The intact and degraded troponin-T bands were quantified, and the final calculation was displayed as the relative percentage of degraded Troponin-T for each sample. Data were analyzed as a completely randomized design with the fixed effect of carcass weight group and the random effect of kill day.

Results: Increased hot carcass weight had a significant effect on Troponin-T degradation. Chops from carcasses in the MHVY and HVY treatments showed a greater (P < 0.05) percentage of degraded Troponin-T than those chops from the MLT and LT groups, with a range of 6.50% to 10.26%. Sarcomere lengths were the same in all weight treatments, except the LT group, which had the longest (P < 0.05) sarcomeres. Mean sarcomere lengths for all treatments were between 1.66 and 1.92 μm. No differences (P > 0.05) were observed for total collagen content across weight treatments, with all collagen content falling between 3.97 and 4.65 mg of collagen per gram of muscle tissue.

Conclusion: In conclusion, chops from the MHVY and HVY treatments had more degradation of structural proteins. Rice et al. (2019) found that consumer and trained panelists ranked the heavier weight treatments more tender despite having the same fat percentage. Our results provide evidence that the slower chill rate of the heavier weight carcasses allows for greater postmortem enzymatic proteolysis, contributing to the observed improved tenderness of heavier weight carcasses.

Keywords: enzymatic proteolysis, heavy weight pigs, pork, sarcomere length, tenderness

41 EFFECT OF SOUS VIDE PREPARATION VERSUS TRADITIONAL PREPARATION ON CONSUMER RATINGS OF BEEF STEAKS FROM VARIOUS MUSCLES

K. A. Bugenhagen^1*, K. R. Vierck¹, M. S. Hernandez², J. W. S. Yancey¹, J. C. Brooks², D. R. Woerner², and J. F. Legako², ¹Department of Animal Science, University of Arkansas, Fayetteville, Arkansas, USA; ²Department of Animal and Food Sciences, Texas Tech University, Lubbock, Texas, USA, *vierck@uark.edu

Objectives: The objective of this study was to determine the viability of sous vide to improve palatability of beef cuts.

Materials and Methods: Chuck rolls, chuck clods, chuck under blades, inside rounds, outside rounds, and strip loins were selected from USDA Low Choice. Subprimals were wet aged at 2°C–4°C in the dark for 21 d. Subprimals were fabricated into 2.54-cm steaks representing the adductor (AD), biceps femoris (BF), chuckeye steak (CHE; longissimus thoracis, complexus, and spinalis dorsi), longissimus lumborum (LL), semimembranosus (SM), serratus ventralis (SV), and triceps brachii (TB). Steaks were randomly assigned to one of 2 cooking treatments, traditional grilling (TRAD) or sous vide cooking followed by finishing on a grill (SVG). Steaks were then packaged and frozen at −20°C. For analysis, steaks were thawed for 24 h, and the steaks designated for SVG were cooked in a circulating hot water bath at 63.5°C for 2 h to a medium-rare doneness (63°C). Immediately prior to serving, steaks were finished on a clamshell grill to a medium degree of doneness (71°C). Steaks that were designated for TRAD were cooked on a clamshell grill to a medium degree of doneness. Steaks were cut into steak thickness × 1 × 1 cm cubes, and 2 cubes were served to each panelist. Untrained consumer panelists (n = 300) evaluated 7 samples for flavor liking, juiciness, tenderness, and overall liking on a 100-point line scale using tablets. Data were analyzed as a 2 × 7 factorial arrangement, with cooking method, muscle, and the interaction serving as fixed effects and panel session serving as a random effect.

Results: There was a method × muscle interaction for overall liking (P = 0.040). For the LL, AD, and SV, the TRAD steaks were rated higher for overall liking (P < 0.05) compared with their SVG counterparts, with marked differences appearing in the LL. In contrast, the SVG TB was rated higher for overall liking (P < 0.05) over the TRAD TB steaks. No differences were observed between SVG and TRAD (P > 0.05) for the BF or SM steaks, which were the muscles preferred the least by consumers compared with all other muscles, regardless of cooking method (P < 0.05). No method × muscle interaction was observed for tenderness, juiciness, or flavor liking (P ≥ 0.070). For cooking method, TRAD steaks were rated higher for flavor, juiciness, and overall liking (P < 0.001). No differences were observed between cooking method (P = 0.595) for tenderness. Within the muscle treatments, TB, LL, and CHE steaks were rated higher for flavor liking (P < 0.05) compared with the SV and AD steaks. However, the BF and SM were the least flavorful (P < 0.05) according to consumers. The CHE, SV, and TB were juicier (P < 0.05) than the SM, AD, and BF. Similar to flavor liking, the BF and SM steaks were the driest and toughest steaks (P < 0.05). The CHE and LL steaks were more tender (P < 0.05) than all other treatments, with the exception of the TB, which was similar (P > 0.05) to the LL.

Conclusion: The results of this study indicate that the cooking method had a substantial impact on consumer ratings, suggesting that consumers will consistently choose TRAD cooking over SVG cooking under these sous vide conditions. TRAD steaks had higher palatability ratings by consumers than sous vide steaks. These results suggest that, regardless of cooking method, high-quality muscles will provide the consumer a quality eating experience.

Keywords: consumer, cooking method, muscle, palatability, sous vide

42 INFLUENCE OF BEEF CARCASS CHILLING RATE ON STEAK CASE LIFE AND QUALITY TRAITS

T. C. DeHaan^1*, L. M. Hite¹, E. R. Gubbels¹, C. E. Bakker¹, A. D. Blair¹, J. K. Grubbs¹, and K. R. Underwood¹, ¹Department of Animal Science, South Dakota State University, Brookings, South Dakota, USA, *trevor.dehaan@sdstate.edu

Objectives: The objective of this study was to determine the influence of beef carcass weight on carcass chilling, pH decline, color, case life, and tenderness of steaks from the round, loin, rib, and chuck.

Materials and Methods: Twelve head of fed beef cattle were slaughtered over 2 d at the South Dakota State University Meat Laboratory. Carcasses were allotted by hot carcass weight (HCW) into Heavyweight (HW; HCW = 450 ± 19 kg) and Lightweight (LW; HCW = 349 ± 34 kg) groups. Data-logging thermometers were placed in the left side of the carcass within the round, loin, rib, and chuck to track temperature decline. A 20-cm logger was placed in the round and chuck, and a 10-cm logger was placed in the loin and rib. During chilling, pH decline was measured in the semitendinosus (ST), longissimus lumborum (LL), longissimus thoracis (LT), and serratus ventralis (SV) for 48 h. Carcass data including 12th rib fat thickness, ribeye area, marbling score, and USDA Yield and Quality Grade were collected approximately 48 h postmortem. Following carcass data collection, sides were fabricated, and the ST, LL, LT, and SV were collected, weighed, and portioned into 2.54-cm steaks. One steak from each muscle was tray overwrapped with a high-oxygen permeable wrap and placed under a simulated retail display for 10 d at which point they were evaluated for instrumental color (Minolta L*, a*, b*), sensory color score, and discoloration each day. Steaks from each muscle were aged 5, 10, 14, or 21 d for Warner-Bratzler shear force (WBSF) analysis. Statistical analysis was conducted using the MIXED procedure of SAS (SAS Institute Inc., Cary, NC) for the effect of treatment, time, and their interaction. Carcass data and muscle weights were analyzed as a completely randomized design. Temperature and pH decline, objective and subjective color, and WBSF were analyzed as repeated measures. Slaughter date was used as a random variable. Significance was considered at P < 0.05.

Results: HW carcasses had heavier (P < 0.05) HCW, and all selected muscle weights, compared with LW carcasses. No effect of HCW or HCW × time (P > 0.05) was observed for pH decline. A HCW × time interaction was observed for temperature decline (P < 0.05) in the rib and round primals. Ribs from HW had increased temperatures (P < 0.05) for the first 25 h of chilling compared with LW but were similar for remainder of chilling period (P > 0.05). Temperature in the round was not different between treatments for first 3 h of chilling (P > 0.05), but HW had increased temperatures for the remainder of chilling (P < 0.05). A HCW × time interaction was detected for WBSF (P < 0.05) and L* values (P < 0.05) in the ST. Steaks from LW carcasses were more tender (P < 0.05) than HW at day 5 of aging but were not different at day 10, day 14, or day 21 (P > 0.05). Steaks from HW were darker (P < 0.05) throughout the display period. On day 1 of retail display, HW steak L* value decreased (P < 0.05), whereas that of the LW steaks increased (P < 0.05). Steaks from the ST from HW carcasses had lower a* and b* values (P < 0.05) than LW steaks. SV steaks from HW carcasses had increased (darker) subjective color scores (P < 0.05) compared with LW steaks.

Conclusion: Heavier beef carcass weights resulted in a more prolonged temperature decline deep in the rib and round. However, only the ST had tougher steaks at early aging days and decreased L*, a*, and b* values in HW carcasses.

Keywords: beef, carcass, meat quality, temperature

43 EXTENDING THE SHELF LIFE OF BEEF BONE-IN SHORT RIB STEAKS USING COMBINATIONS OF ACEROLA CHERRY POWDER AND ROSEMARY EXTRACT

J. B. Van Buren^1*, B. J. Buseman¹, T. M. Weber¹, J. A. Nasados¹, J. M. Lancaster¹, J. H. Smart¹, P. D. Bass¹, and M. J. Colle¹, ¹Animal, Veterinary, & Food Sciences, University of Idaho, Moscow, Idaho, USA, *vanb2144@vandals.uidaho.edu

Objectives: Retailers in South Korea are currently limited in possible sales owing to the rapid discoloration of steaks from beef bone-in short ribs resulting in a 1-day retail shelf life. Improving the shelf life of these steaks by 2 d will improve salability of beef in international markets and thus improve potential profits for producers. The objective of this study was to determine the effect of the topical application of acerola cherry powder and rosemary extract in combination on beef bone-in short rib steak shelf life with regard to color stability and lipid oxidation.

Materials and Methods: Beef bone-in short ribs (Institutional Meat Purchase Specifications #123A; N = 18) from USDA Choice carcasses were purchased from a commercial harvest facility and aged (0°C) for 28 d post fabrication. Following aging, 1.02-cm-thick steaks were cut (perpendicular to the rib bones) and systematically assigned to a treatment based on steak location within the subprimal. Treatments were as follows: untreated control (C) or topically sprayed (2 mL) with a treatment of an acerola cherry powder solution (0.05% A), rosemary extract solution (0.10% R), or mixture of the acerola cherry powder and rosemary extract (M1 = 0.05% A + 0.1% R; M2 = 0.1% A + 0.1% R; M3 = 0.05% A + 0.2% R; and M4 = 0.1% A + 0.2% R). Half of the steaks were assigned by location to day-0 lipid oxidation, metmyoglobin reducing activity, and oxygen consumption; the remaining steaks were assigned to 4 d of retail display followed by day-4 lipid oxidation and metmyoglobin reducing activity. Throughout retail display, steak objective and subjective color was measured once daily for 4 d.

Results: On day 0 and day 4, untreated bone marrow was less red than all of the antioxidant-treated bone marrow (P = 0.011), and bone marrow treated with M1, M2, M3, and R had less discoloration than the untreated control bone marrow (P = 0.016). Steaks treated with M2, M3, M4, and R had a brighter oxygenated lean color (scale: 1–8; bright cherry-red to dark cherry-red, respectively) than the untreated control steaks (P = 0.028). Oxygen consumption and metmyoglobin reducing activity did not differ among treatments (P = 0.570 and P = 0.315, respectively). Steaks treated with M4 did not increase in lipid oxidation from day 0 to day 4, and on day 4, steaks treated with M1, M3, and M4 had less lipid oxidation than the untreated control steaks (P < 0.001). There were differences among treatments (P = 0.034) in retail display fluid loss; however, antioxidant-treated steaks did not decrease fluid loss compared with the untreated steaks.

Conclusion: Applying topical antioxidants improves shelf life stability of beef bone-in short ribs aged for an extended period.

Keywords: antioxidants, beef, extended aging, shelf life

44 LEAN COLOR AND OXIDATIVE BIOMARKERS IN POSTRIGOR LONGISSIMUS MUSCLE FROM BEEF CATTLE INJECTED WITH HYDROGEN PEROXIDE

S. Wang¹, K. V. To^2*, C. B. Dahlgren¹, D. Sajeev¹, D. Rivera³, M. W. Schilling², S. Suman⁴, and T. Dinh¹, ¹Department of Animal and Dairy Sciences and ²Department of Food Science, Nutrition and Health Promotion, Mississippi State University, Starkville, Mississippi, USA; ³Southwest Research and Extension Center, University of Arkansas, Fayetteville, Arkansas, USA; ⁴Department of Animal and Food Sciences, University of Kentucky, Lexington, Kentucky, USA, *sw2447@msstate.edu

Objectives: This study examined the effects of oxidative stress induced by hydrogen peroxide on lean color and oxidative biomarkers in postrigor longissimus muscle from beef heifers (N = 18).

Materials and Methods: Cattle were supplemented with ground corn and soybean hulls to 310 to 456 kg of body weight while grazing on cool- and warm-season pastures and finished at a commercial feedlot in Iowa. Animals were blocked into 3 clusters based on initial biomarkers. Two treatments of either 20 mg of hydrogen peroxide/kilogram of body weight (OX, n = 9) or 10 mL of saline (CON, n = 9) were equally and randomly assigned to animals within each cluster. On the day before slaughter, the OX and CON treatments were administered intravenously through the jugular vein. Samples were collected from the anterior of the longissimus lumborum muscles at 72 h postmortem. Samples were analyzed for thiobarbituric acid reactive substances by extracting malondialdehyde in 10% trichloroacetic acid and reacting with saturated thiobarbituric acid solution (532 nm), for total antioxidant capacity by extracting antioxidants in water and reacting with radicalized ABTS (2,2′-azinobis-[3-ethylbenzothiazoline-6-sulfonic] acid; 734 nm), for glutathione (GSH) by extracting and reducing all glutathione to GSH and reacting with DTNB (Ellman’s reagent; 5,5’-dithio-bis-2-nitrobenzoic acid; 410 nm), for glutathione peroxidase by extracting enzyme in 50 mM Tris-HCl buffer (pH 7.6 with 5 mM EDTA) and being measured by the coupled indirect oxidation of GSH and NADPH (340 nm) to NADP⁺, and for metmyoglobin reducing activity based on the ability of muscle extract in 0.2 mM phosphate buffer (pH 5.6) to reduce horse skeletal metmyoglobin to deoxymyoglobin (580 nm). One steak per animal was also displayed under simulated retail conditions and repeatedly measured for reflectance spectra of 400 to 700 nm in 10-nm intervals and CIE L*, a*, b* values. The L*, a*, b*, and spectra were used to calculate hue angle, chroma, and percentages of deoxymyoglobin, oxymyoglobin, and metmyoglobin. Data were analyzed as a randomized complete block design with treatment as fixed effect, and actual probability values were reported as a single value for a pair-wise comparison or a range of values for multiple pair-wise comparisons. Lean color data were analyzed as split-plot design in time (repeated measurement).

Results: Although the CON had 0.23 mmol Trolox equivalence/kilogram more than OX (P = 0.028), no treatment effect was found for lean color or oxidative biomarkers in postrigor muscles (P ≥ 0.151). Except for day 0, as the steaks continued to bloom, the lean color—despite maintaining its shade (hue, P ≥ 0.363)—had diminished redness (a*, P ≤ 0.007), color intensity (chroma, P ≤ 0.001), and oxymyoglobin percentage as retail display approached day 5 (P ≤ 0.115).

Conclusion: Although hydrogen peroxide injection decreased total antioxidant capacity, such an effect was minimal and did not change lean color or oxidative biomarkers.

Keywords: meat color, beef, oxidative stress

45 POST-TRANSLATIONAL MODIFICATION OF MYOGLOBIN IN POSTRIGOR LONGISSIMUS LUMBORUM MUSCLE FROM BEEF CATTLE INJECTED WITH HYDROGEN PEROXIDE

T. Dinh^1*, S. Li², S. P. Suman², J. Chen³, and H. Zhu³, ¹Department of Animal and Dairy Sciences, Mississippi State University, Starkville, Mississippi, USA; ²Department of Animal and Food Sciences and ³Proteomics Core Facility, University of Kentucky, Lexington, Kentucky, USA, *sw2447@msstate.edu

Objectives: This study examined the effects of oxidative stress induced by hydrogen peroxide on post-translational modification (PTM) of myoglobin in postrigor longissimus lumborum muscle from beef heifers.

Materials and Methods: Cattle were supplemented with ground corn and soybean hulls to 310 to 456 kg of body weight while grazing on cool- and warm-season pastures and finished at a commercial feedlot in Iowa. Animals were blocked into 3 clusters based on the principal component analysis of initial thiobarbituric acid reactive substances, total antioxidant capacity, and ferric-reducing antioxidant power values in blood plasma. Two treatments of either 20 mg hydrogen peroxide/kg body weight (OX, n = 9) or 10 mL of saline (CON, n = 9) were equally and randomly assigned to animals within each cluster. On the day before slaughter, the OX and CON treatments were administered intravenously through the jugular vein. A 2.54-cm longissimus lumborum steak per animal was collected at 72 h postmortem. Myoglobin was purified using sodium dodecyl sulphate–polyacrylamide gel electrophoresis. The protein bands representing myoglobin (17 kDa) were excised and were subjected to in-gel trypsin digestion. The tryptic peptides were extracted, concentrated, and subjected to nano-liquid chromatography tandem mass spectrometry (MS/MS). The MS/MS data were submitted to a local MASCOT server for protein identification against a custom database containing only beef myoglobin. The MS/MS data were searched for the following PTM: methionine oxidation; lysine acetylation; lysine and arginine methylation; serine, threonine, and tyrosine phosphorylation; 4-hydroxynonenal alkylation at histidine and lysine.

Results: Overall, the number of PTM in myoglobin were more in OX (56 PTM) than in CON (47 PTM). Phosphorylation occurred on serine and threonine residues in both CON (9 PTM) and OX (9 PTM), whereas tyrosine was phosphorylated only in CON. Methylation and carboxymethylation were detected in lysine and arginine residues in both CON and OX. Acetylation was observed at 10 lysine residues in OX compared with 6 in CON. The 4-hydroxynonenal alkylation of histidine and lysine residues occurred more in OX (13 PTM) than in CON (8 PTM) myoglobin. Moreover, 4-hydroxynonenal alkylation of distal histidine (His 64), responsible for heme stability, occurred only in OX myoglobin.

Conclusion: The 4-hydroxynonenal modification of His 64 was particularly concerning because it is an indicator of myoglobin oxidation. The occurrence of PTM can compromise myoglobin redox stability and fresh beef color stability. These findings suggest that myoglobin PTM in postmortem skeletal muscles may be exploited as biomarkers of pre-harvest oxidative stress in beef cattle.

Keywords: beef, myoglobin, oxidative stress

46 CHARACTERIZATION AND PATHOGENESIS OF DORSAL RECUMBENCY SYNDROME ASSOCIATED WITH WOODY BREAST IN BROILER FLOCKS FROM ONTARIO, CANADA

S. Che^1*, L. Susta¹, and S. Barbut², ¹Ontario Veterinary College and ²Ontario Agricultural College, University of Guelph, Guelph, Canada, *ches@uoguelph.ca

Objectives: A dorsal recumbency syndrome has been recently described in market-age broiler chickens. Affected birds are flipped onto their backs and unable to right themselves, described by some as “turtle chickens.” These birds can eventually die on the farm and can represent a significant economic loss. Previous reports suggested that breast myopathies such as the woody breast, which is characterized by myodegeneration, inflammation, and scarring of the pectoral muscles, may be associated with this syndrome, as a cause of impaired wing movement (necessary for up-righting the bird). In this study, we aimed to characterize the clinical, pathological, and serum chemistry changes of broiler chickens affected by dorsal recumbency.

Materials and Methods: Samples from 4 different commercial broiler farms were collected between March 2020 and April 2021. A total of 65 broilers (Ross 708), 33 affected and 32 unaffected, were sampled at 42 to 48 d of age. Clinical signs were recorded, serum was collected, and birds were euthanized for postmortem analysis and histopathology. Samples from the pectoralis major of 24 birds (13 affected, 11 unaffected) from 2 of the 4 visits were scored histologically to determine the presence and severity of myopathies. Out of 36 serum samples (18 affected, 18 unaffected) from those 2 visits, serum from 4 affected and 4 unaffected chickens was submitted to the Animal Health Laboratory for a full chemistry profile. All 36 samples were used to determine the level of aspartate aminotransferase and creatine kinase. Student t test and Wilcoxon rank-sum test were used to compare the amounts of serum analytes and histological scores between affected and unaffected birds (P < 0.05).

Results: Sampled flocks included males (3) and mixed sex (1), with a market weight of 2.8 to 4.2 kg. All recumbent birds were bright and alert and could move their legs but had difficulties moving their wings. Mild hydropericardium was observed in 34.4% (95% confidence interval [CI]: 18.6%–53.2%) and 25.0% (95% CI: 11.5%–43.4%) of affected and unaffected birds, respectively; right ventricular hypertrophy was observed in 12.1% (95% CI: 3.4%–28.2%) and 9.4% (95% CI: 2.0%–25.0%) of affected and unaffected birds, respectively. Recumbent birds displayed a significantly higher severity (P < 0.05) of myodegeneration, inflammation, and accumulation of fibro-fatty tissue in the P. major compared with unaffected birds. The level of aminotransferase and creatine kinase of recumbent chickens was significantly higher (P < 0.05) than unaffected birds, suggesting muscular damage.

Conclusion: Serum chemistry and histopathological changes in the P. major suggest an association between breast myopathies and dorsal recumbency syndrome. Recumbent birds showed higher frequency of hydropericardium and right ventricular hypertrophy, suggesting that these lesions may lead to death.

Keywords: biochemistry, broiler chicken, cardiomyopathy, histopathology, woody breast myopathy

47 AN INVESTIGATION ON THE INFLUENCE OF VARIOUS BIOCHEMICAL TENDERNESS FACTORS ON EIGHT DIFFERENT BOVINE MUSCLES

P. A. Hammond^1*, M. D. Chao¹, C. K. Chun¹, W. Wu¹, A. A. Welter¹, T. G. O’Quinn¹, and G. Magnin-Bissel², ¹Department of Animal Sciences and Industry and ²Institute of Computational Comparative Medicine, Kansas State University, Manhattan, Kansas, USA, *pah014@ksu.edu

Objectives: Tenderness is defined as the amount of force required to bite through a piece of meat. Despite its simple definition, 3 factors underlie the complexity of tenderness: the actomyosin, the background, and the bulk density or lubrication effects. However, past studies concluded no single tenderness component can be used to predict beef tenderness for all cuts. Therefore, this study’s objective was to better understand the relationships of various biochemical tenderness-contributing components to the overall tenderness perception of 8 different beef muscles.

Materials and Methods: Gluteus medius (GM), longissimus thoracis (LT), pectoralis profundus (PP), rectus abdominus (RA), rectus femoris (RF), semitendinosus (ST), supraspinatus (SS), and triceps brachii (TB) were collected from 10 UDSA high choice beef carcasses and assigned to a 2- or 21-d aging period (n = 160). Troponin-T (TNT) degradation, collagen content, pyridinoline mature collagen crosslink density, intramuscular lipid content, pH, and trained panel analysis were measured. A Pearson correlation analysis was conducted to determine the relationship between each tenderness contributor measured in this study and the overall tenderness evaluated by the trained panelist.

Results: All cuts increased in TNT degradation from 2 to 21 d postmortem. However, GM and RA displayed the least amount, whereas PP and TB showed the most TNT degradation compared with the rest of cuts after 21 d of aging (P < 0.05). The RF, SS, and PP had the greatest collagen content followed by ST, TB, and GM, with LT and RA having the lowest collagen content (P < 0.01). For pyridinoline density, PP and SS had the greatest densities followed by RA, ST, GM, TB, and RF, with LT displaying the lowest (P < 0.01). The RA and LT displayed the greatest lipid contents, followed by GM, RF, SS, and PP, with ST having the lowest lipid content (P < 0.01). The pH remained constant from 2 to 21 d of postmortem storage for all retail cuts except for LT and GM, which decreased after 21 d of aging (P < 0.01). The RA and SS displayed the greatest pH values followed by RF, TB, PP, ST, and GM, with LT displaying the lowest (P < 0.01). For overall tenderness evaluated by trained panelists, LT received the highest rating followed by TB, RA, RF, GM, ST, and SS, with PP receiving the lowest overall tenderness rating (P < 0.01). The correlation analysis showed that the 8 cuts may have different profiles of tenderness contributors. For instance, overall tenderness for TB, ST, and RA may be driven by TNT degradation (r = 0.55, 0.55, and 0.45, respectively; P < 0.05). On the other hand, overall tenderness for PP may be driven by collagen content (r = −0.48; P < 0.05), and overall tenderness for GM was correlated with lipid content and pH (r = 0.51 and −0.74, respectively; P < 0.05). When all retail cuts were combined and analyzed holistically, all of the biochemical measurements conducted (except for pH) in this study played a small but important role as an overall tenderness predictor (P < 0.01).

Conclusion: The results showed that muscle anatomical locations and physiological functions may explain the majority of the biochemical/tenderness differences found in this study, and 1 to 2 of the major biochemical factors may explain the overall tenderness for each muscle. However, the level of contribution to overall tenderness from each biochemical factor varies greatly from one muscle to another.

Keywords: beef quality, collagen, proteolysis, tenderness, trained sensory panel

48 COMPARISON OF FRESH BELLY AND BACON CHARACTERISTICS BETWEEN COMMERCIAL DUROC-SIRED AND HERITAGE BREED LARGE BLACK PIGS

Y. Guo^1*, K. Sharp¹, B. Richert¹, and S. Zuelly¹, ¹Department of Animal Sciences, Purdue University, West Lafayette, Indiana, USA, *guo335@purdue.edu

Objectives: Consumer demands for healthier products have shaped the industry to produce leaner pork. Large Black Pigs are a pasture-raised heritage breed that is a part of an emerging niche market and has not undergone major genetic selection for percent lean. Therefore, limited data are available comparing Large Black Pigs’ belly and bacon quality traits with those of commercial breeds. The objectives of this study were to examine differences in fresh belly and bacon characteristics between commercial Duroc-sired and Large Black genetic lines fed high forage or commercial diets.

Materials and Methods: Fifty pigs were used in the study, Duroc sired (DS; n = 25 pigs) and Large Black sired (LB; n = 25 pigs). Pigs were assigned to one of 2 dietary treatments: Fiber (Fib) or Control (CON), using a 2 × 2 factorial design of breed and diet. Dietary treatments were fed throughout the grow–finish period (101 or 140 d) in 6 phases. CON diet was corn-soybean meal-DDGS based and Fib diet used increasing amounts of wheat middlings (1%–10%) and dehydrated alfalfa meal (7.5%–20%) to replace corn and soybean meal in the CON diet from phase 1 to 6. Pigs were harvested at a common age, but body weight varied between genetics (DS 125 ± 2.23 kg; LB 99 ± 2.28 kg; P < 0.001). Fresh bellies (Institutional Meat Purchase Specifications #408) were obtained from each carcass and weighed (fresh weight) and measured for firmness by suspending the bellies over a polyvinyl chloride pipe (d = 8.89 cm) with skin side down; a greater distance between the blade and flank ends of a belly indicated increased firmness. Fresh bellies were injected to 110% fresh weight with a manual compressed air stitch pump, thermally processed to 62°C, cooled to 1°C internal temperature, and weighed (cooked weight). Processing yield was calculated as a percentage: (cooked wt/fresh wt) × 100. A 0.64-cm bacon slice was removed at 25%, 50%, and 75% distance from the blade end of the cooked bellies for visual image analysis. Images of the slices were analyzed with Adobe Photoshop for bacon total slice length (SL; cm), total slice area (SA; cm²), and lean area (LA; %). Data were analyzed with breed and diet as fixed effects using RStudio (1.2.1335) with least-squares means separated at P < 0.05.

Results: Results showed differences in firmness due to a breed × diet interaction (P = 0.0527); LB CON were the firmest bellies (P < 0.01), LB Fib were intermediate in firmness (P = 0.0325), and DS CON and DS Fib were not different (P = 0.5577). DS bellies had greater (P < 0.01) processing yield than LB bellies. A tendency for a breed effect was observed in SL with DS slices longer than LB slices (P = 0.065). Diet was significant for SA as slices from CON bellies were larger than Fib slices (P < 0.01). Breed was significant for LA, as DS slices had greater LA than LB slices (P < 0.01). No breed × diet interaction was found in slice images.

Conclusion: This experiment found variations in fresh belly and bacon characteristics between DS and LB genetic lines and their diets. LB bellies had decreased LA, indicating a reduced proportion of lean throughout the belly. This supports the decreased processing yield, as LB bellies would have less protein to absorb brine but improved firmness with more fat. Although LB pork may have niche market value, the integration of this breed into commercial bacon processing has limitations in composition that need to be further evaluated to improve the product’s desirability.

Keywords: bacon, Duroc-sired pigs, heritage breed, Large Black Pigs, pork quality

49 EFFECTS OF FRESH BEEF TUMBLING AT DIFFERENT POSTMORTEM TIMES ON QUALITY AND PROTEOLYTIC ATTRIBUTES OF M. LONGISSIMUS LUMBORUM

M. J. Nondorf^1*, B. Fa², and Y. H. B. Kim¹, ¹Animal Sciences, ²Statistics, Purdue University, West Lafayette, Indiana, USA, *mnondorf@purdue.edu

Objectives: Supplying consumers with consistently tender beef products remains a significant challenge in the industry. While tumbling has been extensively practiced for processed meat with brine addition, tumbling alone is not considered as a means to improve beef tenderness. It has, however, recently been demonstrated that tumbling without incorporation of a brine solution can be successful in improving the instrumental tenderness and consumer liking of tenderness of beef loin (M. longissimus lumborum). At present, though, the time at which the tumbling treatment should be applied to be most effective at optimizing quality attributes remains unclear. The objective of this study was to determine the most effective postmortem timepoint to apply tumbling to enhance tenderness and proteolytic features of beef loin.

Materials and Methods: Beef loin muscles (n = 12; Institutional Meat Purchase Specifications #180, USDA Low Choice) were obtained at 1 d postmortem from carcasses, then sectioned and assigned to tumbling timepoint treatments (non-tumbled [NT], 1 d tumbling, 6 d tumbling, and 11 d tumbling) with equal distribution among muscle positions. Sections were tumbled for 90 min (non-vacuum, 8.5 rpm) at the assigned tumbling time, and then steaks (2 cm thick) were made. Steaks were randomly assigned to either no aging or further aged to a common postmortem time of 16 d. Meat quality measurements included Warner-Bratzler shear force (WBSF), instrumental color, water-holding capacity (WHC), and pH. Western blot analyses of desmin and troponin T degradation, calpain-1 autolysis, and myofibril fragmentation index (MFI) were performed to assess proteolytic activity. All treatment levels were analyzed using one-way analysis of variance and Tukey pair-wise comparison test of SAS version 9.4 (SAS Institute Inc., Cary, NC). Statistical significance level was set at P ≤ 0.05.

Results: Tumbling beef loins at 1 d and 6 d postmortem resulted in lower WBSF values (P < 0.05) compared with the NT controls. Tumbling early postmortem (1 d) with no further aging had similar WBSF values compared with NT loins at 16 d (P > 0.05). Tumbling at 6 d and 11 d with further aging resulted in the lowest WBSF values (P < 0.05), though no differences were found between different tumbling treatments (P > 0.05). In general, fresh beef tumbling had minimal impacts on pH, color attributes, and water-holding capacity, regardless of the timepoint (P > 0.05). Degradation of troponin T and desmin, and calpain-1 autolysis, were not affected by tumbling treatments (P > 0.05), though proteolysis was increased with aging (P < 0.05). Although not significant, numerical increases in MFI were found in samples assigned to tumbling at 1 d and 6 d postmortem. Significant increases in MFI, however, were found in loins assigned to tumbling at 11 d postmortem compared with NT counterparts.

Conclusion: The results of the current study confirm that fresh beef tumbling alone without brine addition can improve beef instrumental tenderness and could considerably shorten postmortem aging times. Furthermore, the current study found that the positive impacts of beef tumbling may be further maximized through early postmortem application, which would likely be attributed to physical disruption to muscle structure coupled with additional enzymatic degradation. Future studies should evaluate the effects of postmortem time of fresh beef tumbling on sensory attributes of beef muscles to identify the optimal process to improve eating quality and product consistency.

Keywords: beef quality, meat tumbling, postmortem proteolysis, tenderness

50 ANAEROBIC DRY AGING OF BEEF

J. Sonderman^1*, S. Lau², F. Ribeiro¹, D. Velazco Marroquin¹, N. Herrera¹, R. Miller³, and C. Calkins¹, ¹Animal Science and ²Food Science, University of Nebraska–Lincoln, Lincoln, Nebraska, USA; ³Animal Science, Texas A&M, College Station, Texas, USA, *joseph.sonderman@huskers.unl.edu

Objectives: Dry aging has recently gained popularity among high-end restaurants and smaller meat packing plants looking to add value to their beef. Dry aging is known for the development of unique flavors via concentration of flavor compounds through dehydration and the creation of new flavors through oxidation and endogenous enzymatic processes. However, prolonged exposure of meat to cooler conditions, which is common practice in dry aging processes, can lead to off-odors and flavors. The objective of this research project was to determine the effects of removing oxygen from the beef dry aging system. The hypothesis was that oxygen removal would result in a reduction/inhibition of oxidative products and a superior dry-aged beef flavor.

Materials and Methods: Boneless upper 2/3 Choice beef strip loins (n = 18) were randomly assigned to 3 aging treatments: wet aging, traditional (aerobic) dry aging, and anaerobic dry aging. All treatments were aged for 41 d at 2°C ± 1°C. The dry-aged treatments were held at 50% relative humidity with a fan speed of 2,200 RPM. Anaerobic dry-aged samples were aged in dry aging chambers housed within an oxygen-impermeable film bubble. Complete anaerobic conditions were not achieved with the system in that the oxygen concentration at the surface of the meat remained 1%–5%. To achieve anaerobic conditions, anaerobic chambers were flushed with an 80% nitrogen (N) 20% carbon dioxide (CO₂) gas mixture at the beginning of aging and any time the oxygen concentration approached 4%. Food-grade oxygen scavengers were also utilized to remove residual oxygen after gas flushing. After the aging process was completed, dry-aged samples were weighed before and after trimming to determine yield.

Results: There was a significant difference in yield between the wet-aged (95% yield) and the 2 dry-aged treatments (P < 0.05), but there was no significant difference between the anaerobic (55% yield) and aerobic (54% yield) dry aging treatments. Trimmed loins were then cut into steaks, packaged, and frozen (−80°C or −20°C depending on analysis) for further analysis. Lipid oxidation was measured using thiobarbituric acid reactive substances. There was no significant difference found in thiobarbituric acid reactive substances between the wet-aged (1.18 mg malonaldehyde/kg of tissue) and anaerobic dry-aged (1.27 mg M/kg) samples (P < 0.05), but there was a significant difference between the aerobic dry-aged (2.46 mg M/kg) samples and the other 2 treatments (P < 0.05). A paired preference test was conducted to determine consumer flavor preference between anaerobic and traditionally (aerobic) dry-aged steaks. Sensory steaks were cooked to medium well (70°C) and then cut to a sample size of 2 cm × 1 cm × 2.54 cm. There were no significant differences found among treatments (P < 0.05). Finally, a trained sensory analysis was conducted. Anaerobic dry-aged samples tended to have more desirable flavor notes, and aerobic dry-aged beef tended to have more undesirable flavor notes.

Conclusion: These results suggest that although anaerobic dry aging significantly reduces lipid oxidation, it is unclear whether this difference is detectable to consumers. More research is required on the pathways of flavor development of dry-aged beef.

Keywords: dry aging, flavor, oxidation

51 COMPARISON OF BONE-IN AND BONELESS AGING OVER EXTENDING AGING PERIODS ON CONSUMER RATINGS OF BEEF LOIN STEAKS

K. A. Bugenhagen^1*, K. R. Vierck¹, M. S. Hernandez², J. W. S. Yancey¹, and J. F. Legako², ¹Department of Animal Science, University of Arkansas, Fayetteville, ²Department of Animal and Food Sciences, Texas Tech University, Lubbock, Texas, USA, *vierck@uark.edu

Objectives: The objective of this study was to evaluate the influence of bone-in aging over extended periods on consumer ratings of beef steaks.

Materials and Methods: Paired short loins were selected from beef carcasses (n = 20) from the upper 2/3rds of USDA Choice (Modest⁰⁰–Moderate¹⁰⁰ marbling scores). Following collection, the right-side short loins were deboned into strip loins, and then each sub-primal was portioned into 3 equal sections. Sections were vacuum packaged and randomly assigned to one of 3 aging periods: 21, 42, or 63 d. After each respective aging period, sections were fabricated into 2.54-cm steaks, and then steaks were vacuum packaged and frozen at −20°C until further analysis. Prior to consumer panel analysis, steaks were thawed at 1°C–4°C for 24 h prior to panels. On bone-in steaks, the bone was retained during cooking. Steaks were cooked on an open-face clamshell grill until internal temperature of 71°C was reached. Immediately prior to serving, steaks were cut into steak thickness × 1 × 1 cm cubes, and then 2 cubes were served to each panelist. Each panelist was served one sample of each treatment in a randomly assigned order and rated each sample for flavor liking, tenderness, juiciness, and overall liking using a digital survey on an electronic tablet. Panelists were also asked to rate each trait as acceptable or unacceptable and assigned a quality level to each sample. Data were analyzed as a split plot design, with sub-primal serving as the whole plot and section serving as the subplot. Aging type, period, and the interaction served as the fixed effects, and panel was incorporated into the model as a random effect. Acceptability data were analyzed as a binomial distribution.

Results: No interaction for aging type × period was observed for any traits evaluated (P ≥ 0.146). Additionally, no differences were observed between aging periods for any traits evaluated (P ≥ 0.078). However, consumers determined that bone-in steaks were juicier (P < 0.05) and preferred bone-in steaks overall (P < 0.05) compared with boneless steaks. No differences were observed between boneless and bone-in steaks for tenderness and flavor liking (P ≥ 0.093). Additionally, no differences were observed between aging type for acceptability of any trait (P ≥ 0.402). However, a greater percentage of consumers rated bone-in steaks as premium quality (P < 0.05) compared with boneless steaks.

Conclusion: These results indicate that, despite anecdotal evidence suggesting a consumer preference for bone-in steaks, they perform similarly to boneless steaks for tenderness and flavor. However, bone-in steaks are juicier and liked more overall by consumers, which indicates a more premium eating experience for the consumers.

Keywords: aging, bone-in, consumers, extended aging, palatability

52 PROFILING FLORIDA RAISED BEEF FOR QUALITY AND TENDERNESS ATTRIBUTES

K. A. Philipps^1*, T. Thrift¹, T. Scheffler¹, J. Scheffler¹, and C. Carr¹, ¹Animal Sciences, University of Florida, Gainesville, Florida, USA, *kphilipps@ufl.edu

Objectives: Improvements in genetics, nutrition, and management practices have positively affected the palatability of beef from Florida-raised cattle, bringing products nearer to the levels associated with beef from the rest of United States. However, industry perceptions of meat quality attributes of Florida cattle have changed relatively little over time, negatively impacting valuation of cattle from the Southeastern region. The objective of this study was to investigate the claim that Florida-raised beef is equal in quality and tenderness to beef produced elsewhere in the United States.

Materials and Methods: Steers (n = 168) from 9 ranches in Florida were finished at a commercial feedyard in North Central Florida. Steers were harvested on 3 dates after 162, 197, and 211 d of feeding when it was visually determined that they had 1.2 cm of backfat. All cattle were harvested at a local packing plant, and carcasses were chilled for 48 h before samples were collected. Approximately 72 h postmortem, two 2.5-cm-thick steaks were cut from the strip loin prior to carcass fabrication, vacuum packaged, and allowed to age in a cooler for 14 d prior to being frozen. Control steaks for comparison were procured from a custom steak cutter (USDA Low Choice). In addition, control strip steaks were procured from a local retail outlet (USDA Select). The strip steaks obtained from the steak cutter (n = 50) and the retail outlet (n = 22) were purchased in similar percentages of Choice and Select to the USDA grade on the Florida cattle. Steaks were vacuum packed and aged for 15 d before freezing. Slice shear force data were obtained for all steaks over a 4-d period. All steaks were thawed for 24 h in a cooler and subsequently cooked to 71°C. Three slice samples were taken from each steak using a 90-degree slice box and sheared on an Instron machine. Trained sensory panel analysis was conducted on all steaks over 27 d. All data were analyzed using SAS (SAS Institute Inc., Cary, NC) with steak origin as treatment and degree of doneness as a covariant.

Results: Steaks from Florida cattle had higher slice shear force values than steak cutter or retail outlet steaks (P < 0.001). Trained sensory panelists did not detect significant differences in Florida cattle compared with steak cutter or retail outlet steaks for tenderness, beef flavor, connective tissue, juiciness, or off-flavor.

Conclusion: Differences in slice shear force values among treatment did not translate to differences in sensory panel values. The majority of the samples tested in this study represent the 100 degrees of marbling between Slight 50 and Small 50. This small range may have contributed to less consistent sensory panel evaluations.

Keywords: beef quality, bos indicus, tenderness

53 PREDICTING CARCASS COMPONENT YIELDS FOR TURKEYS USING SHACKLE IMAGES

H. Hiscock^1*, R. Vanderhout², M. Yahiro¹, B. Wood³, C. Baes², and S. Barbut¹, ¹Food Science and ²Animal Bioscience, University of Guelph, Guelph, Canada; ³School of Veterinary Medicine, University of Queensland, Brisbane, Australia, *hhiscock@uoguelph.ca

Objectives: Yields deriving from the different carcass cut-up parts of a turkey are considered to be major factors in poultry breeding. The yield measurements from each part, including those of high interest for meat production, such as breast, thighs, and drums, are known to have moderate to high heritabilities and therefore have played an essential role in genetic selection. However, manually collecting yield measurements has become problematic, because labor costs can be extensive, especially considering the number of phenotypes that need to be collected in order for it to be relevant for genetic selection. The objective of the current study was to use the data collected from image analysis software of still shackle images in combination with previously recorded weights from different turkey carcass components to create a predictive model for future component yield estimations.

Materials and Methods: In this study, we experimented using a commercial image analysis system, developed primarily for broiler chicken, that is better able to assess this issue. Note that this particular system has never been used to estimate turkeys’ meat yield. The system was originally developed to enable the assessment of the carcass as a whole and then determine its grade for further processing. It uses advanced imaging software to evaluate carcass shape, color, and texture, as well as provides distinct coordinates. The data collected allows for the dimensions of the broiler carcass to be calculated. Images for approximately 10,000 toms originating from 3 different pedigree lines were captured after the carcasses were de-feathered and eviscerated prior to chilling. Commercial processing procedures were met at each stage as conducted in a Canadian government-inspected processing plant. The weight of both pectoralis major and minor were recorded after chilling and meat maturation (24 h). Additionally, one-third of the toms had weights recorded for thighs, drums, wings, scapula, breast skin, and rack.

Results: Moving forward, several predictive models are currently being created and tested using multiple linear regression, regression trees, and neural networks.

Conclusion: The results will provide the industry an advanced, more effective method of turkey carcass yield estimations for both the whole carcass and the parts of interest. In addition, the dimensions of each bird possessed in the study will be saved and aid in future genetic selection within turkey pedigree lines.

Keywords: image analysis, yield

54 A COMPARISON OF MEAT QUALITY AND SENSORY ATTRIBUTES IN FRESH AND FROZEN AMERICAN LAMB USING TWO DIFFERENT MUSCLES

M. Fevold^1*, K. Maddock-Carlin¹, and T. Hoffman¹, ¹Animal Sciences, North Dakota State University, Fargo, North Dakota, USA, michaella.fevold@ndus.edu

Objectives: The objective of this study was to evaluate differences in meat quality and sensory attributes of fresh and frozen lamb using the longissimus lumborum (LL) and semimembranosus (SM) muscles.

Materials and Methods: Dorset wether lambs raised at North Dakota State University (n = 12) were harvested at the North Dakota State University Meats Laboratory. After a 24-h chill, loin and leg subprimals were collected from each carcass. Subprimals were split in half, and each side was assigned to either fresh or frozen treatment. Each half was weighed before being vacuum sealed. Subprimals assigned to fresh treatment were stored in a cooler at 3°C for 14 d, whereas subprimals assigned to frozen treatment were stored in a freezer for 13 d + 1 d of thawing at 3°C. Before fabrication, subprimals were removed from bags and reweighed for primal weight loss. After weighing, loin subprimals were fabricated starting at the cranial end, whereas the SM was removed from the leg subprimal and fabrication began at the distal end. For both muscles, an ∼1.27 cm chop was removed for drip loss analysis, and an ∼2.54 cm chop was fabricated, vacuum sealed, and stored at 3°C for Warner-Bratzler shear force and cook loss evaluation; remaining chop samples were used for sensory evaluation. Drip loss was determined over 24 h from suspended 25-g samples. Warner-Bratzler shear force and cook loss analysis was conducted in accordance with American Meat Science Association (AMSA) guidelines. Sensory evaluation was conducted 24 h after sample fabrication. Consumer panelists (n = 84) were given paired samples of LL and SM and were asked to evaluate overall likeness, flavor like, tenderness like, and juiciness like on a continuous line scale. Data were analyzed using the PROC Mixed procedure SAS Studio^® (SAS Institute Inc., Cary, NC) with means being separated with the PDIFF option and were considered significant when P ≤ 0.05.

Results: No differences were observed between treatments for primal weight loss, cook loss, or Warner-Bratzler shear force in LL-fresh, LL-frozen, SM-fresh or SM-frozen (P ≥ 0.10). However, LL-fresh and SM-fresh samples experienced significantly less drip loss compared with LL-frozen and SM-frozen samples (P < 0.0001, P = 0.0003, respectively). LL-fresh sensory samples had significantly higher overall like, tenderness, and juiciness scores compared with LL-frozen samples (P = 0.01, P = 0.02, and P = 0.03, respectively). However, no differences in flavor scores were observed in LL-fresh samples compared with LL-frozen samples. Additionally, no differences in overall like, flavor, tenderness, or juiciness scores were observed in SM-fresh samples compared with SM-frozen samples (P ≥ 0.77).

Conclusion: Our results indicate no influence on meat quality and sensory attributes of SM to lamb when frozen. Industry application of frozen storage may deem beneficial for supply of legs. However, we did identify negative influence on sensory attributes to lamb LL by freezing, specifically related to water-holding capacity and juiciness. The differences in overall consumer likeness can be attributed to the perceived juiciness and tenderness, whereas flavor profiles of fresh versus frozen lamb were indistinguishable. Therefore, maintaining fresh lamb loin chops in retail and foodservice offer the greatest opportunity for consumer satisfaction.

Keywords: fresh and frozen, lamb quality, sensory attributes

55 EFFECTS OF DIFFERING CARBON DIOXIDE LEVELS ON MEAT COLOR IN MODIFIED ATMOSPHERE PACKAGING

K. Hearn^1*, M. Pfeiffer¹, B. Wilson¹, R. Ramanathan¹, and G. G. Mafi¹, ¹Department of Animal and Food Sciences, Oklahoma State University, Stillwater, Oklahoma, USA, *mdenzer@ostatemail.okstate.edu

Objectives: The most important factor influencing consumers’ purchasing decision of meat is color. Consumers associate a bright cherry-red color in beef with wholesomeness and freshness. Modified atmosphere packaging (MAP) allows removal of or replaces the gaseous environment surrounding a product before sealing the package. Tri-gas (nitrogen 69%, carbon monoxide 0.4%, carbon dioxide variable) carbon monoxide MAP is effective in stabilizing color as the carbon monoxide (CO) binds to the myoglobin and forms carboxymyoglobin. During the COVID-19 pandemic, carbon dioxide (CO₂) was in short supply, and most gas flushes in mother bags or MAP use 30% CO₂. Therefore, the objective of this study was to assess the effect of different CO₂ concentration gas flushes in master packages on the display life of fresh beef.

Materials and Methods: Twenty-five USDA Low Choice ribeye rolls (Institutional Meat Purchase Specifications #112A) were collected from a commercial processing facility. Each subprimal was wet aged for 12 d. After aging, each subprimal was opened and surface sprayed with a proprietary antimicrobial solution. Ribeye rolls were sliced 2.54 cm thick and placed onto foam trays in adjacent pairs (N = 108 trays) with an absorbent pad and over-wrapped with perforated polyolefin film. Trays were randomly assigned to either a 10%, 20%, or 30% CO₂ concentration master bag (n = 27 master bags; n = 9/CO₂ concentration). Three additional master bags per CO₂ concentration were packaged and assigned to headspace analysis. Oxygen, carbon dioxide, and carbon monoxide were evaluated at 0, 6, 24, 30, and 48 h. Three master bags, containing 4 trays, for each CO₂ concentration (10%, 20%, and 30%) were randomly selected for opening after 10, 15, or 18 d of dark storage. Following respective storage, the trays were placed in a retail display case for 5-d color evaluation. Headspace analysis was conducted before each master bag was opened, and objective color measurements were collected on days 0 through 5 of retail display. Muscle color, surface discoloration, and overall acceptability were analyzed daily by a trained panel (n = 6).

Results: Residual oxygen content within master bags containing 20% and 30% CO₂ decreased to 0% in 48 h. However, the master bags flushed with 10% CO₂ contained more O₂ over the entire 48-h period and never decreased below the goal of less than 0.15% residual oxygen. As a result, steaks from master packages flushed with 10% CO₂ darkened and discolored more (P < 0.05) rapidly than steaks from either the 20% or 30% CO₂ concentrations. Additionally, steaks from master bags flushed with the 10% CO₂ concentration were the only steaks in display to reach unacceptable levels. Steaks from master bags flushed with 20% or 30% CO₂ concentration performed comparably (P > 0.05).

Conclusion: The 20% CO₂ concentration master bag flush outperformed the 10% CO₂ concentration in all aspects of the study, as well as surpassed or equaled the 30% CO₂ concentration. Thus, it is recommended 20% CO₂ concentration gas flush of master bags could be utilized by the industry to reduce CO₂ use.

Keywords: carbon dioxide, meat color, modified atmosphere packaging

56 DESCRIPTIVE ASSESSMENT OF DRY-AGED BEEF FROM COMMERCIAL AGING LOCATIONS ACROSS THE UNITED STATES

J. Lancaster^1*, J. Smart¹, J. Van Buren¹, B. Epperson¹, J. Nasados¹, W. Price², M. Colle¹, and P. Bass¹, ¹Animal and Veterinary Science and ²Statistical Programs, University of Idaho, Moscow, Idaho, USA, *lanc6314@vandals.uidaho.edu

Objectives: The effect of dry aging on beef flavor and unique flavor attributes is equivocal in the literature. The objective of this study was to determine the influence of commercial dry aging on the intensity of beef flavor attributes through a trained descriptive sensory panel.

Materials and Methods: Bone-in beef strip loins (NAMI #175) were purchased from a commercial beef plant (N = 66). Samples were obtained from the same lot and date of production. Strip loins were fabricated from carcasses that were identified by United States Department of Agriculture (USDA)–Agricultural Marketing Service grading personnel to meet Certified Angus Beef^® (USDA Schedule G1) brand specifications and were obtained from the left side of each carcass so as to not have duplicate strip loin samples from any single carcass. Six strip loins were shipped to each commercial aging location, aged for 45 d, and returned to the University of Idaho. An additional 6 strip loins were wet aged for 45 d as a negative control. Following aging, strip loins were fabricated end-to-end into 2.54-cm-thick steaks, vacuum packaged, and frozen (−28°C) until further analysis. Trained sensory analysis was performed using the methods described in the American Meat Science Association Sensory Guidelines. In addition, training was developed to calibrate panelists for flavors commonly associated with dry-aged beef: earthy, yeasty, nutty, cheesy, sour, bitter, sweet, and flavor intensity. Data were analyzed using the mixed model and correlation procedures of SAS (SAS Institute Inc., Cary, NC). Significance was determined at P < 0.05.

Results: Dry-aged beef flavor intensity was different among aging locations (P < 0.01). Following additional analysis to separate aging locations among mild and bold flavors, further analysis was conducted within flavor intensity classifications. Among the mild intensity flavor locations, there were differences in cheese flavor notes (P < 0.01). Moreover, among mild flavor intensity locations, there was a positive correlation (r = 0.45; P < 0.01) between earthy and bitter flavors and a negative correlation (r = −0.59; P < 0.01) among yeasty and nutty flavors. Additionally, among the bold intensity locations, there were differences among locations in cheese flavor notes (P < 0.01). Among the bold flavor intensity locations, there was a negative correlation between cheesy and bitter flavors (r = −0.43; P < 0.01), sour and nutty flavors (r = −0.52; P < 0.01), and nutty and bitter flavors (r = −0.59; P < 0.01).

Conclusion: The current research indicates that dry aging imparts distinguishable flavor characteristics on the final dry-aged product wherein distinct differences in commercial dry aging locations can be observed.

Keywords: aging parameters, beef, dry aging, flavor, sensory attributes

57 FREE AMINO ACID CONTENT IN LONGISSIMUS LUMBORUM AND SEMIMEMBRANOSUS MUSCLES FROM ELECTRICALLY STIMULATED BEEF CARCASSES

S. Wang^1*, K. V. To², C. Dahlgren¹, C. Fornes¹, H. Hessler², X. Zhang², Y. Campbell², B. Buseman³, P. Bass⁴, M. Colle⁴, M. W. Schilling², and T. Dinh¹, ¹Department of Animal and Dairy Sciences and ²Department of Food Science, Nutrition and Health Promotion, Mississippi State University, Starkville, Mississippi, USA; ³Department of Animal Science, University of Nebraska–Lincoln, Lincoln, Nebraska, USA; ⁴Department of Animal, Veterinary and Food Sciences, University of Idaho, Moscow, Idaho, USA, *sw2447@msstate.edu

Objectives: Free amino acids in postmortem beef muscles contribute to the development of cooked beef flavor. Both electrical stimulation (ES) and aging increase postmortem proteolysis, thereby accelerating the accumulation of free amino acids in postmortem tissues. This study examined the combined effects of electrical stimulation on free amino acid content in beef longissimus lumborum (LL) and semimembranosus (SM) muscles aged for 1, 4, and 14 d.

Materials and Methods: Twenty-three crossbred beef carcasses were randomized to receive either extra-low voltage (20 V for 20 s) electrical stimulation (ES; n = 11) or non-stimulation (NS; n = 12) at exsanguination. Again at 1 h postmortem, 2 sides of each carcass were randomized to receive either ES or NS, resulting in 2 early ES treatments (ES-ES and ES-NS) and 2 early NS treatments (NS-NS and NS-ES). Samples were removed from the LL and SM for free amino acid analysis on day 1, 4, and 14 postmortem. Free amino acids were extracted in cold water, and the extract was filtered through 0.2-μm and 3-kDa membranes. The amino acids in the filtrate were combined with norvaline as internal standard, derivatized with propyl chloroformate, and determined by gas chromatography–mass spectrometry. Data were analyzed as a split-plot design in time in a generalized linear mixed model, with treatment, day, and their interaction as fixed effects and carcass side within treatment as a random effect. Actual probability values were reported.

Results: Thirty-one amino acids were quantified in beef LL and SM muscles. The predominant amino acids were alanine, β-aminoisobutyric acid, and glycine (553 to 1,901 nmol/g), whereas the least predominant amino acids were cystine, α-aminobutyric acid, and thiaproline (8 to 14 nmol/g). The treatment effect was found only for ornithine in SM (P = 0.030), with early ES treatments increasing ornithine by 15 to 19 nmol/g (P ≤ 0.045). Two-way treatment × day interactions were found for glutamic acid and asparagine in SM (P < 0.001). Glutamic acid remained similar among treatments on days 1 and 4; however, it was increased by 213 to 247 nmol/g on day 14 by early ES compared with early NS (P < 0.001). Asparagine followed a similar pattern with an increase of 20 to 28 nmol/g by early ES on day 14 (P ≤ 0.048) compared with early NS. Other free amino acids in SM, including the most predominant ones, were influenced only by day with day-14 content being the greatest (P ≤ 0.023). In the LL, only day effect was found for 18 amino acids (P ≤ 0.038), including those related to desirable flavors such as glutamic acid (umami) and glycine (sweetness).

Conclusion: Early electrical stimulation influenced the free amino acid content in the SM muscle more than that in the LL muscle. However, aging increased the content of most amino acids across treatments and muscles. These findings suggest that both electrical stimulation and aging can be used to alter the content of water-soluble flavor compounds in beef, which, in turn, influence beef flavor and consumer acceptance.

Keywords: beef flavor, water-soluble, amino acids

58 IMPACT ON ANTIMICROBIAL INTERVENTIONS ON SPOILAGE BACTERIA DURING EXTENDED STORAGE OF RAW, VACUUM-PACKAGED BEEF FROM TWO FACILITIES

S. Watson^1*, R. Furbeck¹, B. Chaves², S. Fernando¹, and G. Sullivan¹, ¹Animal Science and ²Food Science, University of Nebraska, Lincoln, Nebraska, USA, *swatson13@huskers.unl.edu

Objectives: Fresh, chilled, vacuum-packaged beef accounts for an estimated $4 billion of the annual US beef export market. Retarding microbiological spoilage is a crucial step in improving the shelf life and adding value to the sector. Organic acid antimicrobials are one method used to address spoilage organisms unique to an individual processing facility. The objective of this study was to determine the effect of processing plant and organic acid treatment on the microbial profile of raw beef products.

Materials and Methods: Beef chuck rolls (Institutional Meat Purchase Specifications #116A, N = 24) were obtained from 2 different processing facilities on 2 different days of production. On day 7 postmortem, 6 chuck rolls from a single plant and processing day were cut in half and assigned to one of 4 treatments: 4.5% lactic acid, 2.5% Beefxide, 380 ppm peroxyacetic acid, or a no-treatment control. Each half-chuck roll was cut into at least six ∼1 kg pieces, submerged into the assigned organic acid solution for 15 s, allowed to drip for 2 min, and individually vacuum sealed. Samples were stored at 2.7°C for 112 d. On day 0 (day of organic acid treatment) and every 28 d thereafter, aerobic, anaerobic, psychrotrophic, lactic acid bacteria, and Pseudomonas plate counts were measured on a single piece. A 100-g sample was cut from the surface of each piece and stomached with 100 mL of buffered peptone water. Homogenate was plated in duplicate onto brain heart infusion agar for aerobic, anaerobic, and psychrotrophic plate counts; deMan Rogosa Sharpe agar for lactic acid bacteria; and cephaloridine fucidin cetrimide agar for Pseudomonas. Aerobic, anaerobic, lactic acid, and Pseudomonas plates were incubated at 37°C for 48 h. Psychrotrophic plates were incubated at 4°C for 10 d. The experiment was conducted in 2 independent replications, with 1 d of production from each facility included in a single replication. Samples stored for 56 d from the second location were not evaluated owing to a laboratory closure that prevented sampling. Data were analyzed as an incomplete block design with 2 locations, 4 treatments, and 5 sampling days in SAS version 9.4 (SAS Institute Inc., Cary, NC).

Results: Bacterial counts increased during storage across all microbial populations (P < 0.01). The impact of treatment was only significant for the Pseudomonas counts (P = 0.04), in which lactic acid (P = 0.01) and Beefxide (P = 0.03) treatments had lower Pseudomonas concentrations than the control group. Pseudomonas (P < 0.01) and psychrotrophic (P < 0.01) counts were lower in samples from location 1. Anaerobic (P = 0.04) and lactic acid bacteria (P < 0.01) counts were lower in samples from location 2.

Conclusion: Bacterial counts increased during storage, and differences between treatments and locations were minimal. Although significant differences existed between locations, these differences were less than 1 log and may not be biologically relevant. No treatment impacted the concentrations of lactic acid bacteria, suggesting that organic acids have little to no effect on the growth of lactic acid bacteria in raw, vacuum-packaged meat. Lactic acid and Beefxide were able to retard the growth of Pseudomonas compared with untreated control samples. Collectively, this suggests that the use of organic acids for shelf life extension should target specific groups of spoilage bacteria.

Keywords: beef, export, microbial spoilage, organic acids

59 VALORIZATION OF GRAPE POMACE FOR A FUNCTIONAL ADDITIVE IN HAMBURGER PATTIES

A. C. Pereira^1*, R. Lammert², D. Ma ³, C. Immoos², and I. Kang³, ¹Food Science, ²Chemistry & Biochemistry, and ³Animal Science, California Polytechnic San Luis Obispo, San Luis Obispo, California, USA, *acpereir@calpoly.edu

Objectives: Conversion of food wastes into functional products can create a win-win situation with food waste reduction, value addition, and additional income to product growers. The purpose of this research was to assess antioxidant activity and phenolic content of seed and seedless pomaces as well as evaluate product quality and sensory attributes of hamburger patties made with grape pomace.

Materials and Methods: Two types of white-wine grapes (Malvasia and Sauvignon Blanc) were obtained from a commercial winery vineyard. The impurities (vine, branches, and leaves) of the grapes were manually removed before producing grape pomace by squeezing using a pressor. The pomace was then separated into seed and seedless pomace. The pH and instrumental color of pomace were measured. Following pulverization of dried seeds and freeze-dried seedless pomace, using liquid nitrogen, both seed and seedless pomace were subjected to an ABTS and Folin-Cioulteau assays to measure the relative ability of antioxidants and total phenols, respectively. Hamburger patties were prepared with seeded pomace using 0% control, 5% Malvasia, and 5% Sauvignon Blanc, which were vacuum packed and stored at −21°C until further use. Frozen patties were thawed and cooked to an internal temperature of ∼76.7°C using a conventional oven prior to wrapping and chilling. Cooked patties were measured for instrumental color and cooking loss. Consumer sensory analysis was conducted using a 50-person sensory panel for appearance, aroma, overall, taste, juiciness, sweetness, texture, firmness, after taste, and willingness to buy. Data in 3 replications were statistically analyzed using the GLM procedure of SAS (SAS Institute Inc., Cary, NC) as a completely randomized design. If significance was determined (P < 0.05) in the model, dependent variable means were separated using the least means significant difference procedure of SAS.

Results: Results of ABTS assay indicated that Sauvignon Blanc seeds possessed higher radical scavenging activity than Malvasia (P < 0.05). A similar trend was observed in the seedless pomace although the activity was relatively lower than that of the seeds (P < 0.05). Malvasia seeds showed higher phenolic content than Sauvignon Blanc; however, no difference of phenolic content was found between the 2 pomaces (P < 0.05). Sauvignon Blanc pomace displayed more yellowness (*b) than Malvasia pomace, with no differences in brightness (L*) or redness (a*). No pH difference was found between the 2 pomaces (P < 0.05). Upon cooking, control patty showed more lightness (L*), redness (a*), and yellowness (b*) than those of pomace patties (P < 0.05). No significant difference of cooking yield was found, regardless of treatment. No significant difference of sensory attributes was observed for hamburger patties regardless of treatment (P < 0.05).

Conclusion: Based on these results, addition of white wine grape pomaces may increase antioxidant activity and phenol level and increase health benefits of hamburger patties. The prospect of reducing the waste issue of grape pomace with the potential of additional income to grape processors is a step toward a more sustainable food chain. Further research is required to evaluate the benefits of grape pomaces from other grapes such as red wine grape and juice type grape in various processed meat products such as sausage, meat ball, meat loaf, ground meat, etc.

Keywords: antioxidants, grape pomace, hamburger patty, phenol, sensory

60 SHELF LIFE EXTENSION OF RAW GROUND TURKEY USING VINEGAR AND NATURAL FLAVORS

S. Baker^1*, G. McCoy¹, D. Unruh¹, S. LaSuer¹, and R. Ames¹, ¹Corbion, Corbion, Lenexa, Kansas, USA, *daniel.unruh@corbion.com

Objectives: This study quantified the ability of Vinegar and Natural Flavor (V/NF) and Natural Flavor (NF) to enhance the oxidative stability of fresh ground turkey while minimizing quality impacts.

Materials and Methods: Fresh, ground turkey was received at the Corbion meat processing facility, approximately 24 h postmortem. The ground turkey was mixed in 40-pound batches for 3 min, following the addition of 1.05% V/NF or 0.95% NF. Following mixing, 200-g samples were portioned into 3 mil vacuum bags, vacuum sealed, and stored at 3.3°C. Samples were stored in the dark, to simulate vacuum packaging in a light-impermeable film. Samples were analyzed throughout the cold storage period (21 d) for instrumental color (HunterLab, L*a*b*), oxidative rancidity (TBA value), and sensory attributes (descriptive analysis). Instrumental color was collected on the same 8 samples throughout the duration (day 0, 2, 7, 9, 14, 16, 21) of the shelf life study. Similarly, 200-g samples were collected at selected dates (day 0, 7, 9, 14, 16, 20) throughout the shelf life and stored at −80°C until TBA analysis was performed. Finally, sensory analysis was performed at day 1 and 14, using a trained sensory panel. Members were trained to specifically recognize oxidized, warmed over, or rancid off-flavors.

Results: The application of V/NF and NF at 1.05% and 0.95%, respectively, enhanced the oxidative stability of fresh ground turkey while minimally impacting the fresh meat color and organoleptic properties of the cooked product. After 20 d of storage, the TBA value of the samples treated with V/NF (0.289 mg MDA/kg sample) and NF (0.250 mg MDA/kg sample) were below the detectable sensory threshold of 0.50 mg MDA/kg sample. In contrast, the TBA value of the control (1.42 mg MDA/kg sample) far surpassed the previously stated sensory threshold. Additionally, no significant differences in color (L*a*b*) values were observed with respect to treatment throughout the storage period. Finally, no significant differences (P < 0.05) were observed between the control samples and the samples treated with the V/NF and NF, 1 d post production, when the samples were analyzed using a trained sensory panel.

Conclusion: Throughout a 20-d shelf life, the inclusion of V/NF and NF inhibited lipid oxidation. Therefore, the application of V/NF and NF may be used to extend the shelf life of fresh ground turkey, without negatively impacting the organoleptic properties of the fresh or cooked ground turkey.

Keywords: color stability, sensory attributes, turkey

61 GENETIC PARAMETER ESTIMATES FOR MEAT QUALITY TRAITS IN CANADIAN TURKEYS (MELEAGRIS GALLOPAVO) USING GIBBS SAMPLING

R. Vanderhout^1*, M. Yahiro², H. Hiscock², J. Mohr³, S. Barbut^2,4, B. Wood^1,3,5, and C. Baes^1,6, ¹Centre for Genetic Improvement of Livestock and ²Department of Food Science, University of Guelph, Guelph, Canada; ³Hybrid Turkeys, Hendrix Genetics, Kitchener, Canada; ⁴Adaptation Physiology, Wageningen University, Wageningen, The Netherlands; ⁵School of Veterinary Science, The University of Queensland, Gatton, Australia; ⁶Institute of Genetics, University of Bern, Bern, Switzerland, *rvande02@uoguelph.ca

Objectives: With an increasing number of poultry meat products being downgraded owing to poor quality and muscle myopathies, the use of genetic selection for meat quality traits in turkeys should be considered. Selection for meat quality has been successfully implemented in other livestock species, and adaptation of these programs could be applied in turkey breeding. The objective of this study was to estimate the heritabilities and phenotypic correlations of several common meat quality traits to evaluate their selection potential in turkeys.

Materials and Methods: Pedigree toms from 7 genetic lines were processed at a commercial facility where live weight at slaughter and whole breast muscle weight (weight of both Pectoralis major and minor) were recorded. P. major (fillet) ultimate pH, color (CIELAB values), drip loss, cooking loss, and shear force were also measured. White striping was rated by several recorders using a 1–4 scale. The heritability for each trait was estimated using Gibbs sampling implemented in the BLUPf90 family of programs. Genetic line, hatch week, and slaughter date were included as fixed effects in each univariate model with the addition of recorder as a fixed effect when analyzing white striping score.

Results: Moderate positive correlations were observed between breast muscle weight and fillet lightness (L*), yellowness (b*), and cooking loss (r = 0.24, 0.20, and 0.18, respectively) showing that larger birds tended to have lighter, more yellow fillets with lower water-holding capacity during the cooking process. Moderate negative correlations were observed between ultimate pH and L*, drip loss, and shear force (r = −0.27, −0.17, and −0.16, respectively). Negative correlations between pH and lightness, drip loss, and shear force are well documented in relation to pale soft exudative meat and were expected. The other notable correlation was between breast meat yield and white striping score (r = 0.10) showing that birds with larger breast muscles relative to body weight tended to have higher white striping scores. High heritability estimates were observed for live weight (h² = 0.56; SD = 0.023; N = 19,655), breast muscle weight (h² = 0.49; SD = 0.022; N = 19,957), and breast meat yield (h² = 0.41; SD = 0.021; N = 19,527), which is typical of growth traits. Ultimate pH (h² = 0.30; SD = 0.044; N = 3,181) along with L* (h² = 0.22; SD = 0.019; N = 13,782), a* (h² = 0.27; SD = 0.018; N = 13,782), b* (h² = 0.24; SD = 0.018; N = 13,782), and white striping score (h² = 0.19; SD = 0.018; N = 12,826) all showed moderate heritability. The estimates calculated in this study for ultimate pH and fillet color were similar to previously published estimates in turkeys. Drip loss (h² = 0.03; SD = 0.022; N = 3,171), cooking loss (h² = 0.09; SD = 0.029; N = 3,221), and shear force (h² = 0.07; SD = 0.041; N = 2,620) all had low heritability estimates and were low compared with previous estimates in broilers, pigs, and lambs.

Conclusion: The parameters estimated in this study show great potential for the incorporation of meat quality traits in turkey selection programs to improve the overall quality of breast meat and reduce the occurrence of myopathies such as white striping. This study is part of a larger project considering the selection of turkeys for improved meat quality.

Keywords: Gibbs sampling, heritability, meat quality, turkeys, white striping

62 ROLE OF THE CALPAIN-CALPASTATIN SYSTEM IN TENDERNESS OF LONGISSIMUS LUMBORUM IN BRAHMAN AND ANGUS STEERS

C. Gingerich^1*, M. McKinney¹, B. Hawryluk¹, P. Ramos^1,2, C. Carr¹, J. Scheffler¹, S. Matarneh³, and T. Scheffler¹, ¹Department of Animal Sciences, University of Florida, Gainesville, Florida, USA; ²Department of Animal Sciences, University of Sao Paulo, Piracicaba, Brazil; ³Nutrition, Dietetics, and Food Sciences, Utah State University, Logan, Utah, USA, *tscheffler@ufl.edu

Objectives: Proteolysis and tenderness are important focuses for meat quality in Brahman, which tend to be tougher with more variability. Although the calpain-calpastatin system is largely responsible for postmortem tenderization, variability in system’s content and activity within the Brahman is not well understood. Therefore, the objectives were 1) to determine calpain activity and calpastatin content in the longissimus lumborum (LL) of Angus and Brahman and 2) to determine calpastatin content in the LL in tough and tender Brahman.

Materials and Methods: For the first study, Brahman and Angus steers (n = 14 per breed) were raised together and harvested. Samples of the LL were taken at 1, 3, 6, and 24 h and 14 d postmortem, frozen in liquid nitrogen, and stored at −80°C until further analysis. For calpain activity, samples from all timepoints were pulverized, diluted with extraction buffer, and homogenized. Then supernatants were plated with a fluorescent substrate. Buffers were added to measure calpain activity with and without calcium added. Calpastatin content of 1 and 24 h samples were evaluated using Western blotting, and the intact band was quantified. Data were analyzed using SAS (SAS Institute Inc., Cary, NC) with fixed effects of breed (b), time (t), and their interaction (b×t). The second study utilized LL from only Brahman steers; samples were sorted into tough (n = 11) and tender (n = 10) based on trained sensory panel scores of 14-d aged steaks. Calpastatin content was evaluated as described for the first study. Data were analyzed with fixed effects of tenderness group (td; tough vs. tender), time (t), and their interaction (td×t). Time was used as a repeated measure for both studies.

Results: In the first study, Brahman exhibited less calpastatin degradation from 1 to 24 h (b×t, P = 0.02). Brahman had greater calpastatin content (P < 0.05) at 1 and 24 h compared with Angus. Calpain activity with added calcium decreased over time (t, P < 0.0001), and Angus tended to have higher activity (b, P = 0.07) compared with Brahman. Calpain activity without calcium decreased more rapidly in Angus (b×t, P < 0.05). In the second study, calpastatin levels at 1 h were higher than 24 h (P < 0.0001). However, neither td group (P = 0.37) nor td×t (P = 0.97) affected calpastatin content.

Conclusion: Increased Brahman calpastatin and less degradation of the protease over time from the first study may suggest more inhibited calpain activity, thus blocking postmortem degradation. This combined with the trend in decreased calpain activity may explain the differences between the tenderness across breeds. However, within the Brahman breed, variable calpastatin levels did not distinguish tough from tender Brahman. Further exploration is needed to fully understand the mechanisms that ultimately decide postmortem tenderness differences in Brahman.

Keywords: calpain-1, calpastatin, tenderness

63 IMPACT OF MATERNAL NUTRITION ON POSTNATAL GROWTH OF CROSSBRED BEEF STEERS

K. F. Oliver^1*, J. B. Van Buren¹, J. B. Hall^1,2, M. L. Heimbuch¹, J. A. Nasados¹, P. D. Bass¹, and M. J. Colle¹, ¹Animal, Veterinary, & Food Sciences, University of Idaho, Moscow, Idaho, USA; ²Nancy M. Cummings REEC, University of Idaho, Carmen, Idaho, USA, *koliver@uidaho.edu

Objectives: Maternal nutrition of beef cows is critical to programing the fetus for improved performance and meat quality. Cows pastured on range often have reduced forage quality compared with cows on irrigated pasture (IRR). Therefore, the objective of this study was to determine the effects of maternal nutrition on the subsequent growth and carcass characteristics of castrated male offspring from multiparous crossbred beef cows that were pastured on IRR versus rangeland (RAN) during early and mid-gestation.

Materials and Methods: Twenty-four crossbred steers were weaned from their dams, which were pastured on IRR or RAN during early and mid-gestation. Twelve steers were from IRR dams, and 12 steers were from RAN dams. After weaning, steers were placed on a backgrounding diet for 4 wk, designed to promote a weight gain of 1.1 kg/d, before being transitioned to a finishing ration. Steers remained on the finishing ration until backfat reached 1.02 cm over the 12th and 13th rib prior to harvest. Weaning weights were adjusted to 205 d of age—after backgrounding weights/initial feedlot weights—and day-160 feedlot weights were collected. Additionally, average daily gain for the backgrounding and feedlot phases were calculated. Data were analyzed using the MIXED procedure of SAS (SAS Institute Inc., Cary, NC). Significance was determined at P < 0.05.

Results: Adjusted weaning weights were greater (P = 0.0107) for IRR compared with RAN steers, whereas initial feedlot weights were not different (P = 0.6943) between the 2 groups. RAN steers had higher average daily gain in both the backgrounding (P = 0.0069) and in the feedlot (P = 0.0022) phases. Therefore, on day 60 of the finishing ration, RAN steers weighed more than IRR steers (P = 0.0299), at 617.8 kg versus 586.0 kg, respectively. The initial data suggest that RAN steers are exhibiting compensatory growth post weaning and have improved performance during not only the backgrounding phase but also the finishing phase.

Conclusion: Understanding the impact of maternal environment on steer calf performance will provide an opportunity for the industry to produce more acceptable products for consumer consumption.

Keywords: beef, carcass, fetal programming, growth

64 COLOR QUALITY OF BEEF FROM CATTLE FED HIGH LEVELS OF VITAMIN E FOLLOWING PROLONGED AGING

N. J. Herrera^1*, J. Sonderman¹, D. Velazco Marroquin¹, P. Vahmani², and C. Calkins¹, ¹Animal Science, University of Nebraska-Lincoln, Lincoln, Nebraska, USA; ²Animal Science, UC Davis, Davis, California, USA, *nherrera18@huskers.unl.edu

Objectives: Meat color is the most important factor influencing consumers’ initial meat purchasing decisions. In products with prolonged aging times, such as commodity exports, accelerated oxidation can occur, resulting in shortened retail display time and negative flavor attributes. We hypothesized that the use of high levels of the antioxidant Vitamin E (α-tocopherol) may retard oxidation rates in beef aged a prolonged period of time. Our objective was to evaluate the impact of feeding high levels of Vitamin E on meat color quality in beef striploins after prolonged aging compared with beef from the general population.

Materials and Methods: Crossbred Bos taurus taurus cattle (n = 150) across 15 pens (n = 10/pen) were grain finished on corn-based rations and supplemented with 2,200 International Units (IU) of Vitamin E for the final 100 d on feed. One Low Choice strip loin was selected from one carcass per pen (n = 15). Additionally, Low Choice strip loins (n = 15) were selected for controls from the packing plant which harvests locally produced, corn-fed Bos taurus taurus cattle. Loins were split into thirds, and each third was randomly assigned to 3, 6, or 9 wk of postmortem storage in vacuum packages. After aging, loins were cut into one 2.54-cm steak for instrumental and subjective color analysis across 7 d of retail display. Two 1.27-cm steaks were fabricated and halved for lipid oxidation after 0, 4, or 7 d of retail display. Steaks used for retail display were placed on foam trays, overwrapped with an oxygen-permeable film, and placed under simulated retail display conditions up to 7 d at 3°C. Thiobarbituric acid reactive substance values were measured on days 0, 4, or 7 of retail display. Instrumental color and delta E (overall color change over time) values were measured via colorimeter measuring L* (lightness), a* (redness), and b* (yellowness). Subjective discoloration was also evaluated daily during retail display by a panel of 5 trained panelists using a percentage scale where 0% = no discoloration and 100% = complete surface discoloration.

Results: A treatment-by-age-by-retail display interaction (P < 0.0001) in percent discoloration occurred, as lower discoloration occurred in Vitamin E loins across 3, 6, and 9 wk of aging. A treatment-by-retail display interaction (P < 0.0001) occurred for a* (redness), as Vitamin E loins exhibited greater a* values across 3, 6, and 9 wk of aging. This was supported by delta E values, as control loins had larger delta E values compared with Vitamin E loins (P < 0.05). Vitamin E loins had less (P = 0.03) lipid oxidation compared with control loins at 3, 6, and 9 wk of aging. Although some differences in the corn-based diets may have occurred, the magnitude of these color differences strongly suggest that feeding high levels of Vitamin E to cattle sustained meat color and oxidative stability during prolonged aging compared with beef obtained from the general population.

Conclusion: Results from this study support the feeding of high levels of Vitamin E to ensure color quality of beef undergoing extended aging.

Keywords: discoloration, oxidation, prolonged aging, retail display, Vitamin E

65 THE IMPACT OF FAT CONTENT LABELING ON CONSUMER SENSORY EVALUATION OF 80/20 GROUND BEEF

M. Mushrush^1*, K. M. Harr¹, E. S. Beyer¹, S. G. Davis¹, K. J. Farmer¹, M. D. Chao¹, J. L. Vipham¹, M. D. Zumbaugh¹, and T. G. O’Quinn¹, ¹Animal Sciences and Industry, Kansas State University, Manhattan, Kansas, USA, *mmushrush@ksu.edu

Objectives: The purpose of this study was to evaluate the effect of providing consumers information related to the fat content of ground beef patties prior to sample evaluation on palatability traits.

Materials and Methods: From the same production day and lot, 80% lean/20% fat ground beef chubs (n = 15) were obtained from a commercial source. Individual chubs were randomly assigned to one consumer panel session, and patties were randomly assigned to one of 6 different labeled fat contents: 90% lean/10% fat (90/10), 80% lean/20% fat (80/20), 73% lean/27% fat (73/27), plus 2 treatments labeled as “lean” or “extra lean,” as well as an unlabeled treatment (NONE). Ground beef was formed into 151.2 g patties (approximately 13 cm diameter; 1 cm thick) using a commercial patty press 11 d after manufacture. All patties were cooked to a medium (71°C) degree of doneness on a clamshell grill. Before sampling, consumers were provided information about the informed fat content, but information was withheld for the NONE sample. Samples were evaluated by consumers (n = 105) for juiciness, tenderness, texture, flavor liking, overall liking, and purchasing intent. Consumers also rated each sample as acceptable or unacceptable within each trait. A 0- to-100-point continuous line scale was used for each trait evaluation and rating. Percentage change of consumer ratings from the NONE sample were found utilizing the following equation: (consumer trait scores – consumer NONE scores)/consumer NONE scores. A completely randomized design was used for data analysis.

Results: There were no differences (P > 0.05) for tenderness, flavor liking, texture liking, overall liking, or purchasing intent among treatments. For juiciness acceptability, 90/20 was rated lower (P < 0.05) than 80/20, 73/27, and NONE but was similar (P > 0.05) to the lean and extra lean samples. There was no difference (P > 0.05) in the percentage change in ratings among the fat treatments across all palatability traits. When evaluating tenderness acceptability, extra lean had the lowest (P < 0.05) percentage but was similar (P > 0.05) to the NONE and lean samples. Additionally, 80/20, 73/27, and NONE samples had a greater (P < 0.05) percentage of samples rated acceptable for juiciness compared with 90/10. Lean and extra lean samples were similar (P > 0.05) to 90/10 for the percentage of samples rated acceptable for juiciness. There were no differences (P > 0.05) among treatments for the percentage of samples rated acceptable for flavor, texture, or overall acceptability. When evaluating the change in acceptability ratings due to labeling, there were no differences (P > 0.05) among treatments for flavor, texture, and overall acceptability. However, labeling with fat percentage had less (P < 0.05) of an impact on tenderness acceptability for extra lean as compared with 90/10, 80/20, and 73/27 samples. Fat labeling resulted in less (P < 0.05) change in the percentage of samples rated acceptable for juiciness for extra lean and 90/10 samples than 80/20 and 73/27 samples.

Conclusion: Ground beef samples with high fat labels resulted in increased juiciness ratings as well as a higher percentage of patties rated acceptable for juiciness. However, the reverse was not observed for lower-fat-percentage samples nor for samples labeled lean or extra lean. This provides evidence that consumer eating perceptions are influenced by fat percentage labeling, but the impact is greater with higher-fat products.

Keywords: consumer, fat content, ground beef, lean, palatability

66 CHARACTERIZING GROUND BEEF THROUGHOUT VARIOUS STORAGE LENGTH INTERVALS FOLLOWED BY SIMULATED RETAIL DISPLAY

I. M. Lovell^1*, C. R. Ritchie¹, B. Bisha¹, and C. L. Gifford¹, ¹Animal Science, University of Wyoming, Laramie, Wyoming, USA, *cody.gifford@uwyo.edu

Objectives: The objective of this study was to conduct 2 separate experiments to characterize shelf life characteristics of ground beef formulations throughout various intervals of dark storage followed by retail display under different lighting conditions.

Materials and Methods: In experiment 1, ground beef in clear chub packaging in 2 lean:fat formulations (81:19 and 73:27) were procured from a federally inspected commercial processor. Ground beef packages were stored in darkness for intervals of 7, 11, 15, 19, 23, and 27 d post grinding. At each storage interval, packages of the same lean formulation were blended together. Approximately 454 g of each ground beef blend were portioned onto polystyrene trays and overwrapped with polyvinyl chloride film. Trays were randomly allocated to initial analysis or assigned to continuous fluorescent or light-emitting diode (LED) lighting for 36 or 72 h of simulated retail display in a refrigerated room at −1.0°C to 1.0°C with no additional ambient light. In experiment 2, beef trimmings were course and fine ground to produce 454 ± 20 g ground beef (approximately 85:15 lean:fat) rollstock packages. Package seals were evaluated prior to randomly subjecting packages to dark storage, full light (continuous fluorescent or LED), or intermittent light (12 h of fluorescent or LED light exposure followed by 12 h of dark storage) for 6, 12, or 18 d post grinding. Objective color (L*, a*, b*) scores, aerobic bacterial counts and lipid oxidation (TBARS) were evaluated at each storage or display interval in both experiments. In experiment 2, an additional set of objective color scores were recorded after packages of ground beef were exposed to oxygen and allowed to bloom for at least 20 min on each microbiological sampling day.

Results: The interaction between storage time (day 7, 11, 15, 19, 23, or 27 of dark storage), display time (initial analysis or 72 h), and lean formulation (81:19 or 73:27) was significant (P < 0.05) for a* values, indicating that a* values decreased with increased dark storage and display time, and lower a* values were detected from the 73:27 lean formulation throughout all sampling times. However, source of light (LED or fluorescent) did not impact L* or a* values among ground beef in experiment 1. Aerobic bacterial counts increased (P < 0.05) between early and late storage intervals and due to display time. In experiment 2, packages of ground beef stored for 12 d post grinding that were allowed to bloom had higher (P < 0.05) L* values and lower (P < 0.05) a* and b* values than packages sampled at 6 or 18 d post grinding and allowed to bloom at final sampling. Lower (P < 0.05) a* values resulted among packages stored in intermittent light after exposure to oxygen at final sampling.

Conclusion: These results suggest that storage interval, display time, and lean formulation influence ground beef characteristics in continuous intervals of storage. This information will be beneficial for future replications and additional work evaluating changes in ground beef throughout storage.

Keywords: ground beef, objective color, shelf life characteristics

67 EVALUATION OF CARBOXYMYOGLOBIN FORMATION IN GROUND BEEF WITH DIFFERING FAT PERCENTAGES

T. Roser^1*, K. Hearn¹, M. Pfeiffer¹, R. Ramanathan¹, and G. Mafi¹, ¹Animal and Food Sciences, Oklahoma State University, Stillwater, Oklahoma, USA, *gretchen.mafi@okstate.edu

Objectives: Meat color is one of the most important visual attributes consumers use when purchasing fresh beef. Myoglobin in the form of oxymyoglobin and carboxymyoglobin (COMb) results in a bright cherry-red color, desired by consumers. COMb denatures slower during the cooking process than oxymyoglobin; thus, persistent pinking of cooked meat can result. The objective of this study was to evaluate COMb formation and persistent pinking differences in ground chuck and ground round patties.

Materials and Methods: Two USDA Choice (Institutional Meat Purchase Specifications #116) chuck rolls and 2 USDA Choice inside rounds (Institutional Meat Purchase Specifications #184) were collected from a commercial packing facility. The subprimals were wet aged for 12 d. Cuts were cubed and ground separately to produce ground round and ground chuck. Proximate analysis was conducted to ensure target lean to fat ratios of ground round (90:10) and ground chuck (80:20). Ground beef from each anatomical location was separately formed into 225-g patties. Patties were placed onto foam trays (n = 48 patties) with an absorbent pad and over-wrapped with polyvinylchloride film. Trays were randomly assigned to 16 master bags (MB) with 3 trays each. Twelve MB were flushed with a 20% CO₂, 0.4% CO, 79.6% N (Trigas) blend with the remaining 4 bags sealed with ambient air as controls. Bags were placed in dark storage until opening at 24 h and 8 d. Patties stored for 8 d in dark storage were then placed in simulated retail display for 2 d (10 d total before analysis). Before opening each MB, headspace analysis was conducted to determine percentage CO₂, CO, and O₂ remaining. Upon opening, HunterLab measurements were taken on all patties; 2 patties were cooked to evaluate persistent pinking, and 1 patty was used for thiobarbituric acid reactive substances analysis. The formation of COMb was confirmed by measuring ratio of absorbance at 543 nm/581 nm. Patties were cooked to an internal temperature of 71°C and placed on ice for 5 min to reduce post-cooking temperature rise. Patties were then removed and cut parallel to surface to measure color with HunterLab (3 readings per patty).

Results: Raw patties from control MB regardless of anatomical location were less red (P < 0.05) than patties flushed with the Trigas blend. Patties in dark storage for 8 d and retail for 2 d had greater COMb formation than patties stored for 24 h. Also, on day 10 (2 d retail display) uncooked ground round patties were redder (higher a*; P < 0.05) than the ground chuck patties. At 24 h, all raw patties were lighter (higher L*; P < 0.05) than patties stored until day 10 (8 d of dark storage and 2 d of retail display). On day 10, raw patties flushed with the Trigas blend were significantly (P < 0.05) lighter than patties packaged with ambient air. Cooked patties stored 10 d were redder (P < 0.05) than patties stored 24 h. Cooked ground chuck patties on day 10 were darker (lower L*; P < 0.05) than ground round patties and ground chuck patties cooked after 24 h of storage. Lipid oxidation of patties was higher (P < 0.05) in patties stored 10 d compared with 24 h.

Conclusion: Patties flushed with Trigas blends forming stable COMb cause increased persistent pinking and can lead to consumer confusion when cooking these patties. Thus, additional research should be conducted to better understand the relationship of lean:fat ratios and dark storage times resulting in increased persistent pinking.

Keywords: carboxymyoglobin, meat color, persistent pinking

68 COLOR AND LIPID STABILITY, FREE AMINO ACID PROFILE, AND FLAVOR OF WET- AND DRY-AGED BEEF LOINS FROM CATTLE FED ULTRAHIGH DOSES OF VITAMIN E

D. Velazco Marroquin^1*, N. Herrera¹, J. Sonderman¹, R. Miller², S. Wang³, T. Dinh³, and C. Calkins¹, ¹Animal Science, University of Nebraska, Lincoln, Nebraska, USA; ²Animal Science, Texas A&M University, College Station, Texas, USA; ³Animal & Dairy Sciences, Mississippi State University, Mississippi State, Mississippi, USA, *dvelazcomarroquin2@huskers.unl.edu

Objectives: Dry-aged beef has a unique flavor, partly because of prolonged exposure to oxygen and lipid oxidation. The experiment tested the hypothesis that feeding ultrahigh doses of Vitamin E would reduce lipid oxidation and stabilize color during dry aging and retail display and support the development of desirable flavors compared with the general population of fed beef.

Materials and Methods: Cattle (n = 150; 10/pen) were grain-finished with the dietary addition of 2,200 international units (IU) of Vitamin E (α-tocopherol) per head per day. One Low Choice carcass was selected per pen (n = 12). Low Choice control carcasses (n = 12) were randomly selected from commercial, fed-cattle production (which are typically fed ca. 50 IU/d). Strip loins within Vitamin E and control treatments were randomly assigned to wet or dry aging for 42 d. After aging, the longissimus lumborum muscle of a 1.27-cm steak from each loin was isolated and cut into equal-sized rectangles. One-half was immediately frozen at −80°C, while the other was subjected to retail display conditions for 8 d while covered with an oxygen-permeable, polystyrene film. Lipid oxidation was measured using thiobarbituric acid reactive substances (TBARS) on day 0 and 42 of aging and after 8 d of retail display. Free amino acids were measured on day 0 and day 42 of aging. Percentage discoloration during retail display was rated daily. A colorimeter measured L*, a*, and b* values using D65 illumination, 2-degree standard observer, and an 8 mm aperture. Data were analyzed as a 2 × 2 factorial with repeated measures over time. Least-squares means were determined by day, with significance noted at a P < 0.05 and a Tukey-Kramer adjustment for multiple comparisons.

Results: On day 0, control and treatment loins did not differ in lipid oxidation (P = 0.936). On day 42, control dry-aged and control wet-aged loins had the highest TBARS values, and Vitamin E wet- and dry-aged loins had lower TBARS values (P = 0.043). After 8 d of retail display post aging, control dry-aged and control wet-aged steaks had the highest TBARS values, and Vitamin E wet- and dry-aged steaks tended to have lower TBARS values (P = 0.085). Free amino acids related to positive beef flavor attributes (such as leucine, isoleucine, valine, glycine, and glutamic acid) were higher (P < 0.05) for samples dry aged for 42 d than wet-aged samples. Trained sensory panelists generally noted more positive flavor notes and fewer negative flavor notes in dry-aged beef from Vitamin E steaks compared with dry-aged control steaks. There was a three-way interaction for discoloration between treatment (control vs. Vitamin E), aging type (dry vs. wet aging), and retail display day (P < 0.0001). Wet-aged controls discolored fastest, followed by dry-aged controls and wet-aged Vitamin E samples. Dry-aged Vitamin E samples had the lowest discoloration. There were aging-by-day and aging-by-treatment interactions for a* values (P > 0.0001 and P = 0.0104, respectively). Generally, Vitamin E–treated samples sustained higher redness values for longer times.

Conclusion: Dietary supplementation of ultrahigh levels of Vitamin E can decrease the negative flavors produced by oxidation while maintaining the unique flavor characteristics of dry-aged beef, minimizing oxidation and stabilizing color.

Keywords: color, dry aging, free amino acids, oxidation, Vitamin E

69 THE EFFECT OF GRAZING BOTANICALLY DIVERSE PASTURE ON THE FATTY ACID PROFILE AND VITAMIN E CONTENT OF BEEF

M. Kearns^1*, J.-C. Jacquier¹, S. Harrison¹, R. Cama-Moncunill¹, T. Boland¹, H. Sheridan¹, and F. J. Monahan¹, ¹School of Agriculture and Food Science, University College Dublin, Dublin, Ireland, *michelle.kearns@ucdconnect.ie

Objectives: A desire for more biodiverse and sustainable pasture-based feeding systems for ruminants has led to growing interest in the use of botanically diverse pasture to improve the nutritional profile of beef. The aims of the study were to determine the impact of grazing 3 different pasture types on the fatty acid profile and Vitamin E (α-tocopherol and γ-tocopherol) content of beef.

Materials and Methods: Hereford × Holstein Friesian male calves (n = 60) were assigned to one of 3 grazing treatments (n = 20 per treatment): a monoculture (perennial ryegrass [PRG] [Lolium perenne]), a two-species pasture (perennial ryegrass and white clover [PRG + WC] [Trifolium pratense]), and a mixed species pasture (MS; perennial ryegrass, timothy [Phleum pratense], white clover, red clover [Trifolium repens], chicory [Cichorium intybus], and plantain [Plantago lanceolata]). Following slaughter and postmortem ageing, α-tocopherol and γ-tocopherol concentrations were determined by high performance liquid chromatography and fatty acid methyl esters by gas chromatography. Statistical analysis was performed in R. Statistical analysis involved one-way analysis of variance followed by Tukey’s post hoc test.

Results: Total polyunsaturated fatty acid (PUFA) proportions were higher (P < 0.01) in the MS beef compared with the PRG and PRG + WC beef. The MS beef had higher proportions of C18:2n6 (P < 0.001), C18:3n3 (P < 0.001), and C20:3n6 (P < 0.01) compared with PRG and PRG + WC beef. The ratio of PUFA to saturated fatty acids and n-6 to n-3 PUFA were higher (P < 0.01) for the MS beef compared with PRG and PRG + WC beef. α-Tocopherol concentration was higher (P < 0.05) in muscle from PRG beef compared with beef from MS animals, but PRG + WC beef was not significantly different from either.

Conclusion: Grazing animals on botanically diverse pasture affected the fatty acid profile and Vitamin E content of the meat. MS beef has a higher proportion of PUFA and a lower concentration of α-tocopherol, which may result in meat that is more prone to oxidation and quality deterioration.

Keywords: beef, fatty acids, nutritional composition, pasture-fed, Vitamin E

70 RELATIONSHIP OF BEEF CARCASS YIELD ATTRIBUTES TO QUALITY GRADE OUTCOMES

B. Grimes^1*, T. Tennant¹, L. Lucherk¹, T. Montgomery¹, T. McEvers¹, and T. Lawrence¹, ¹Beef Carcass Research Center, West Texas A&M University, Canyon, Texas, USA, *bgrimes@wtamu.edu

Objectives: Carcass yield attributes are assumed to be strongly associated with quality grade. Carcass data from individual animals (n = 644,745) collected by the Beef Carcass Research Center from 1992 to 2021 were utilized to quantify the relationships between carcass yield attributes and the probability of a carcass grading USDA Choice or better.

Materials and Methods: Yield attributes included hot carcass weight (HCW), ribeye area (REA), 12th rib subcutaneous fat thickness, calculated yield grade, and HCW to REA ratio (RATIO). Logistic regression analyses were used to calculate the probability of the binary response variable of carcasses grading Choice or better (yes or no). Linear regression was used to determine specific points at which a carcass reaches USDA Choice.

Results: HCW was linearly (P < 0.01; c = 0.57) associated to the probability of carcasses grading Choice or better. The average carcass reached USDA Choice at 283.2 kg; a 1% change in probability of grading Choice occurred concomitant with each 7.7 kg change in HCW. Backfat was also strongly associated (P < 0.01; c = 0.67) in a curvilinear manner to the probability of a carcass grading Choice or better. On average, a carcass achieved USDA Choice at 0.91 cm of 12th rib subcutaneous fat depth. Between 0 and 2 cm of 12th rib subcutaneous fat, a 1% increase in the probability of grading Choice occurred with the addition of 0.0357 cm of backfat. However, the increase in grading Choice or better slowed in relation to subcutaneous fat accrual between 2 and 3 cm of 12th rib fat depth; a 1% increase in Choice or better grading required the addition of 0.0667 cm of backfat. The relationship of quality grade and the primary carcass metric of muscling, REA, is known to be antagonistic in nature. As REA increased, the probability of grading USDA Choice or better decreased; a 1% change in probability of grading Choice occurred with a 0.39 cm² change in REA. The probability of achieving Choice or better by yield grade was represented by a positive quadratic relationship (P < 0.01; c statistic = 0.68); the average carcass achieved USDA Choice at a yield grade of 2.29 and accrued 1% increase in Choice carcasses with each additional 0.0723 units of yield grade. The probability of a carcass grading Choice or better decreased as the RATIO increased. According to the expected RATIO reported on a USDA dot grid, a carcass is required to have 11.81 cm² of REA for each 45.35 kg of HCW. A carcass with a RATIO of a 1.83, the standard expected from the USDA REA:HCW relationship used in yield grading, had a 52% probability of grading Choice or better, whereas a 1% change in Choice or better was caused by a 0.0274 unit change in RATIO.

Conclusion: These data support the knowledge that carcass fat attributes are strongly associated with quality grade outcomes and further supports the antagonistic relationship between carcass muscling and fat deposition.

Keywords: carcass, fat, quality, ribeye area, yield

71 PREDICTION OF COLOR STABILITY OF BONELESS PORK CHOPS USING EARLY AND AGED QUALITY TRAITS

K. Barkley^1*, D. Boler², B. Harsh¹, and A. Dilger¹, ¹Animal Sciences, University of Illinois, Urbana, Illinois, USA; ²Fresh Pork Research, Topigs Norsvin USA, Burnsville, Minnesota, USA, *kaylaeb2@illinois.edu

Objectives: Meat discoloration is known to be related to some quality traits, such as ultimate pH, water-holding capacity, and color. Because of this relationship, quality traits may be predictive of the amount of discoloration that develops during retail display. Such relationships might allow for selection to improve color stability of pork. Therefore, the objectives were to use early and aged pork quality traits to develop regression models for the prediction of instrumental and subjective pork discoloration over time.

Materials and Methods: Boneless loins were collected from 468 pigs in multiple groups. Early quality measurements were collected on the ventral face of 202 loins at the approximate location of the 10th rib at 1 d postmortem. Ultimate pH, CIE L*, a*, and b*, and visual NPPC color, marbling, and subjective firmness were evaluated. These same traits were collected on all loins after 11 or 14 d of postmortem aging with the addition of purge loss. Then, a 2.54-cm chop was cut from each loin at the approximate location of the 10th rib for retail display. Chops were individually placed on 13 × 13 cm Styrofoam trays, overwrapped using oxygen-permeable polyvinylchloride film, and displayed under constant lighting for 7 d. On each day of display, visual discoloration and instrumental color measurements were recorded. Visual discoloration was evaluated using a 10-cm line scale anchored at 0%, 50%, and 100% discoloration. A Hunter spectrophotometer was used to collect reflectance data, which was used to calculate 630/580 nm ratio and metmyoglobin (MMb) content. The REG procedure of SAS (SAS Institute Inc., Cary, NC) was used to develop prediction models for changes (day 7 to day 1) in 630/580 nm ratio, MMb content, and visual discoloration percentage using a stepwise selection method and early or aged traits as independent variables.

Results: From day 1 to day 7 of display, changes in 630/580 nm ratio values ranged from |0.35| to |1.66| units, changes in MMb content ranged from 2.28% to 40.56%, and changes in visual discoloration scores ranged from 0% to 54%. Early quality traits were able to predict 33% (R² = 0.33) of variation in 630/580 nm ratio, 36% (R² = 0.36) of variation in MMb content, and 44% (R² = 0.44) of variation in subjective discoloration score over time. Aged quality traits were able to predict 63% (R² = 0.63) of variation in 630/580 nm ratio, 61% (R² = 0.61) of variation in MMb content, and 37% (R² = 0.37) of variation in subjective discoloration score over time. Among early traits, pH explained the greatest proportion of variation in MMb content (partial R² = 0.32) and subjective discoloration (partial R² = 0.30), whereas a* explained the most variation in 630/580 nm ratio (partial R² = 0.22). Among aged traits, purge loss explained the majority of variation in 630/580 nm ratio (partial R² = 0.37) and MMb content (partial R² = 0.41), whereas L* explained the majority of variation in subjective discoloration (partial R² = 0.25). Increases in redness and pH resulted in decreased discoloration over time, whereas increases in L* and purge loss resulted in increased discoloration.

Conclusion: Both early and aged traits were able to predict the extent of discoloration in pork chops. Aged traits were more predictive of instrumental measures (MMb content, 630/580 nm ratio), whereas early traits were more predictive of subjective discoloration. Overall, loins that were darker, redder, and had greater pH values had better color stability over time.

Keywords: color, color stability, discoloration, pork, prediction

72 EVALUATING THE EFFECTS OF STANDARDIZATION METHODS ON NIX PRO AND HUNTERLAB READINGS

A. Carlock^1*, M. Denzer¹, M. Pfeiffer¹, G. G. Mafi¹, and R. Ramanathan¹, ¹Animal and Food Sciences, Oklahoma State University, Stillwater, Oklahoma, USA, *ranjith.ramanathan@okstate.edu

Objectives: Meat color is considered the most important quality attribute that influences consumer purchasing decisions. Handheld spectrophotometers such as HunterLab (HL) or Minolta are used to objectively measure meat color. Recently, the Nix Color Sensor Pro has been tested in meat color research because of its inexpensiveness and user-friendly interface. Prior to measurement, the HL is standardized with manufacturer recommendations. However, no standardization step is involved in Nix color measurements. Previous research focused on bloomed steaks to determine the correlation between Nix and HL. However, limited knowledge is available on how Nix captures color changes from red to brown. Therefore, the first objective of this study was to investigate the correlation between the HL and Nix for a* color measurements with different types of standardization. The second objective was to determine the ability to quantify discoloration over time using Nix and HL.

Materials and Methods: Eight USDA Low Choice short loins were collected from a beef processor 5 d postmortem. The longissimus lumborum (LL) and psoas major (PM) muscles were separated from short loins and were sliced into 1.9-cm-thick steaks (n = 8). For objective 1, 4 standardization approaches with the HL were assessed: no standardization through polyvinyl chloride overwrap (PVC), standardization through PVC, no standardization through vacuum packaging (VP), and standardization through VP. For retail comparisons, standardization through PVC was evaluated, and for research comparisons, standardization was through VP. Steaks were allowed to bloom for 1 h, then packaged in PVC and held in coffin-style retail cases for display period. For objective 2, LL color was measured on display days 0, 3, 6, and 8. For the PM, color was measured on display days 0, 2, and 4. CIE a* was measured on each instrument and standardization combination for each muscle and display day to determine correlation and quantify discoloration. Proc Univariate, Proc Corr (r), and linear best fit (R²) were determined using SAS (SAS Institute Inc., Cary, NC) separately for LL and PM. The standardization method with the best fit was utilized for further analysis.

Results: There were effects of standardization approach on color readings. LL steak color readings taken after standardizing and through VP film resulted in the best fit (R² = 0.86) and correlation of r = 0.93 between the 2 instruments on day 0. However, the best fit and correlation decreased for LL color readings taken through VP with the transition from bright red to brown with storage time. On day 8, color readings taken on LL steaks with no standardization of the HL but read through PVC increased best fit and correlation. The PM for both instruments reading through VP film without standardizing the HL resulted in the best fit and correlation on day 0 and 4 than day 2 (day 4 > day 0). However, during the transition from red to brown, the best fit and correlation were lower for color readings taken through VP film. These results indicate the Nix is less sensitive in quantifying color changes during retail display.

Conclusion: The user-friendly nature of Nix will allow for its potential use to determine color changes under retail or industry conditions. The current research indicates that, if both Nix and HL are used, researchers may need to take precautions in the standardization step to get comparable data.

Keywords: meat color, HunterLab, NIX, beef color

73 OHIO BEEF QUALITY AUDIT–2021: SURVEY OF CARCASS CHARACTERISTICS RELATED TO QUALITY ATTRIBUTES

B. M. C. Garcia^1*, S. Boyles², J. Rumble³, B. Bohrer¹, A. Relling², and L. G. Garcia¹, ¹Animal Science/Meat Science, ²Animal Science, and ³Agriculture Communication Education Leadership, The Ohio State University, Columbus, Ohio, USA, *garcia.951@osu.edu

Objectives: The National Beef Quality Audit (NBQA) was developed to “benchmark” the status of the US beef industry. Since the first NBQA in 1991, much progress has been made in beef production systems fulfilling beef packing plants’ needs demanded by consumers. To date, a beef quality audit has yet to be conducted in individual states, such as Ohio. With an estimated number of 300 federally inspected and state-inspected meat plants, the collection of beef carcass data could serve to assist beef producers in modifying their livestock practices to reach their end goal. Therefore, the objective was to audit various small-scale meat processing plants to provide a benchmark of the beef industry in Ohio.

Materials and Methods: Ohio meat processing plants (n = 16) slaughtering beef carcasses were selected to contribute data of beef carcass characteristics. Beef carcasses (n = 371) included in the audit were ribbed between the 12th and 13th ribs and allowed to bloom for 20 min. Carcass characteristics were evaluated for yield grade (YG) (back fat thickness [centimeters], loin muscle area [square centimeters], kidney, pelvic and heart fat [percentage], and hot carcass weight [kilograms]), quality grade factors (skeletal maturity, lean maturity, and marbling score) and external fat color. Tools used for evaluation include a USDA Preliminary Yield Grade Ruler (back fat thickness), ribeye dot grid (loin muscle area), USDA Marbling Cards (marbling scores), and a color reference guide. Statistical analysis included arithmetic means by MEANS SAS procedure, least-squares means and standard error of the mean by PROC GLIMMIX SAS procedure, and frequency distributions by Excel.

Results: Mean YG factors were as follows: backfat thickness: 1.1 cm; loin muscle area: 82.0 cm²; kidney, pelvic, and heart fat: 1.6%; and hot carcass weight: 343.1 kg. The mean YG was 2.6 with frequency distributions of 21.3% YG 1, 48.5% YG 2, 23.4% YG 3, 5.6% YG 4, and 1.4% YG 5. Mean quality grade factors were as follows: skeletal maturity: A⁸⁹; lean maturity: A⁸³; and marbling score: Small⁵⁵. The mean quality grade was Select⁴³ with frequency distributions of 5.4% Prime, 62.6% Choice, 17.5% Select, 6.7% Standard, and 8% other (USDA Commercial, Utility, Cutter, or Canner). External fat color resulted in the mean 2.3 (Creamy White).

Conclusion: The in-progress Ohio Beef Quality Audit–2021 currently demonstrates similarities to beef characteristics at the national level. As the first of its kind at a state level, more is to consider for future audits. The current audit primarily serves as a starting point in collecting beef carcass data to assist beef producers in better understanding what is produced. This understanding could lead to modifying livestock practices to better fit the needs of the Ohio beef industry. However, more research and data collection are warranted to accurately compare the Ohio beef industry to that of the United States (OBQA vs. NBQA 1991–2016).

Keywords: beef, beef grading, National Beef Quality Audit, Ohio

74 VOLATILE AROMA COMPOUNDS OF GRILLED CHOPS FROM LAMBS FED NOVEL HIGH-ANTHOCYANIN CORN COBS

M. E. Hawkins^1*, C. R. Kerth1, D. G. Quadros², T. R. Whitney², and W. Xu³, ¹Animal Science, Texas A&M University, College Station, Texas, USA; ²AgriLife Research, Texas A&M University, San Angelo, Texas, USA; ³AgriLife Research, Texas A&M University, Lubbock, Texas, USA, *makennaelisehawk@tamu.edu

Objectives: Oxidative stability is important to improve meat flavor. It was hypothesized that feeding high-anthocyanin (Hi-A™; anthocyanin is an antioxidant) corn cobs as roughage to 30 Rambouillet ewe lambs would improve volatile aroma compounds.

Materials and Methods: The experiment consisted of 3 treatments, Hi-A (an experimental variety) corn cob, Low-A (commodity grade) corn cob, or Hay (Bermudagrass) diets, with 10 animal replications each. Each experimental diet contained 20% roughage (High-A, Low-A, or Hay) and 80% concentrate, which included cottonseed meal, corn, molasses, and minerals. After a 63-d finishing period, the lambs were harvested, and the carcasses were chilled for 14 d (4°C). Boneless loin chops (2.5 cm thick) were fabricated, vacuum packaged, and frozen (−10°C) until analyzed. Chops were thawed (4°C) for 24 h and then placed on a 204°C flat-top grill. When the chops reached an internal temperature of 35°C, they were flipped and removed when they reached 70°C internally. The chops were immediately cut into 11-cm cubes, and 5-g samples were placed in a 20 mL glass vial while the chop was still hot; the headspace was collected by solid-phase microextraction for 30 min. Each solid-phase microextraction was desorbed and then analyzed using gas chromatography/mass spectrometry. Volatile aroma compounds were expressed as log_n(x+1) total ion counts area under the curve. Data were analyzed by analysis of variance for a completely randomized design with diet as the fixed effect and animal as a random effect with an alpha of 5%.

Results: Five volatile compounds were affected by the diets. Both 2-butanone (fruity-green aroma) and 2,3-butanedione (buttery aroma) tended (P = 0.07 and 0.05, respectively) to be greater in chops from lambs fed the Hay diet than those fed the Hi-A corn cob diet—neither of which differed (P > 0.05) from lambs fed the Low-A diet. The compound 2-propanone (pungent aroma) was greater (P = 0.01) in chops from lambs fed the Hay diet than those fed either the Low-A or Hi-A diet, which were similar (P > 0.05). Both 3-methyl-butanal (malty aroma) and methyl benzene (sweet aroma) were lower (P = 0.01 and 0.02, respectively) in chops from lambs fed the Hi-A diet than those fed either the Hay or Low-A diets, which were similar (P > 0.05).

Conclusion: The results suggested that feeding lambs Hi-A corn cobs altered the composition of volatile compounds in the boneless lamb loin chops. Volatile aroma compounds perceived as fruity-green, buttery, pungent, malty, and sweet were more apparent in chops from lambs fed either the positive or negative control diets, suggesting that feeding lambs a Hi-A corn cobs diet could improve the cooked aroma in boneless loin chops.

Keywords: anthocyanin, antioxidants, lamb flavor, volatile flavor compounds

75 EARLY POSTMORTEM PH DECLINE RATE IN THE PORK LOIN SIGNIFICANTLY CORRELATES WITH ULTIMATE PH

N. Matthews^1*, B. Fields¹, and A. Sosnicki¹, ¹Applied Meat Science, PIC North America, Hendersonville, Tennessee, USA, *neal.matthews@genusplc.com

Objectives: Most pH decline curve (PHDC) work has focused on intervals of 1 h or more postmortem, and much of this research has been conducted with conventional carcass chilling (minimum temperature > −5°C) combined with electrical stunning. We believe the PHDC in commercial production systems with group pig movement CO₂ stunning and blast chilling (minimum temperature < −10°C) may be very different than that presented in the literature. The focus of this research was to measure PHDC in shorter time intervals in commercial slaughter plants to determine the shape of the PHDC and determine the intervals where pH decline rate (ΔpH; rate of pH decline per hour) is crucial for development of ultimate pH (pHu; 20 h).

Materials and Methods: Loin (≈10th rib) pH and temperature were collected in 32 carcasses from 4 different plants (n = 6–12/plant). Reed Instruments SD-230 Dataloggers were fitted with Reed TP-07 temperature probes and Hanna FC200B pH electrodes allowing for data collection in 1-min intervals starting at 40 min postmortem. Data points from every 5 min (40 to 120 min postmortem), 15 min (45 to 300 min postmortem and 40 to 55 min postmortem), 30 min (1 to 10 h postmortem), and 60 min (1 to 20 h postmortem) were used to determine ΔpH for each 5-, 15-, 30-, and 60-min intervals. Data were analyzed using the PROC CORR procedure of SAS (SAS Institute Inc., Cary, NC) to determine correlations. Regression models for determining pHu were generated using the PROC STEPWISE procedure of SAS and MAXR selection with independent variables including all ΔpH variables as well as 40-min pH (pHi). Only models with all variables significant at P < 0.10 were deemed valid.

Results: The pHi averaged 6.37 (6.03 to 6.85), and 20-h pH averaged 5.79 (5.43 to 6.02). All times of pH measurement were correlated with 20-h pH (P < 0.001) with r = 0.70 at 40 min postmortem, linearly decreasing until 75 min postmortem (r = 0.55), and then began to increase until reaching r = 0.99 from 15 to 19 h postmortem. The average PHDC generated from these data is different from pH curves using 1- or 2-h intervals. The main differences occur during the first 4-h postmortem with many of the ΔpH at 15-min and 30-min time intervals being very slow to no decline or even slightly increasing in pH. Regression models for 1 (R² = 0.49), 2 (R² = 0.73), 3 (R² = 0.80), 4 (R² = 0.86), 5 (R² = 0.90), 6 (R² = 0.95), 7 (R² = 0.97), 8 (R² = 0.98), 9 (R² = 0.99), and 10 (R² = 0.99) variable models (VARM) were generated for determining pHu (all independent variables were significant in the models, P < 0.05). All models included pHi, and the only 5-min interval variable used was ΔpH45/50 min in the 3, 4, 5, and 6 VARM. After the 5 VARM, the models used more 15-min ΔpH than any other time interval. No model contained more than one 30-min ΔpH variable. The 60-min ΔpH variables were not included in any model before the 6 VARM and no more than 3 times in a single model. The majority of ΔpH variables occurred before 5 h postmortem. The exceptions included ΔpH 330 to 360 (3, 4, and 5 VARM), ΔpH 480 to 540 (6, 7, 8, 9, and 10 VARM), and ΔpH 900 to 960 (10 VARM).

Conclusion: These data indicate that determining ΔpH in 15-min intervals is important in explaining variation in pHu and better quantifying the shape of the pH curve in modern commercial facilities using CO₂ stunning with blast chilling systems. Future work will include evaluation of the ΔpH time intervals that contribute to the development of pork color, firmness, and water-holding capacity.

Keywords: decline rate, pH, pork, quality

76 PREDICTABILITY OF ULTIMATE PH IN PORK LOIN BASED ON POSTMORTEM TEMPERATURE DECLINE

N. Matthews^1*, B. Fields¹, and A. Sosnicki¹, ¹Applied Meat Science, PIC North America, Hendersonville, Tennessee, USA, *neal.matthews@genusplc.com

Objectives: It is accepted that postmortem (PM) temperature decline rate in pig longissimus muscle influences ultimate pH (pHu; 20 h). We are unaware of any work to use individual temperature along the temperature decline curve to predict pHu, and thus precisely modify carcass chilling to attain a desired pHu. This research was conducted to determine whether loin temperature PM can predict pHu.

Materials and Methods: Loin (≈10th rib) pH and temperature were collected in 32 carcasses from 4 different harvest plants (n = 6–12/plant). Reed Instruments SD-230 Dataloggers were fitted with Reed TP-07 temperature probes and Hanna FC200B pH electrodes allowing for data collection in 1-min intervals starting at 40 min PM. Data points from every 5 min (40 to 120 min PM), 15 min (120 to 300 min PM), 30 min (5 to 10 h PM), and 60 min (10 to 20 h PM) were used for correlation and prediction equation analysis. The 40-min pH (pHi) was included in prediction equations because it explains the variability in pHu due to perimortem stress before chilling. Correlations were determined using the PROC CORR procedure of SAS (SAS Institute Inc., Cary, NC). Regression models for determining pHu were generated using the PROC STEPWISE procedure of SAS and MAXR selection with independent variables including all timepoints of temperature and pHi. Models with all variables significant at P < 0.10 were deemed valid.

Results: The pHi averaged 6.37 (6.03 to 6.85), and 20-h pH averaged 5.79 (5.43 to 6.02). The 40-min temperature averaged 38.8°C (32.7°C to 40.8°C), 3-h temperature averaged 15.7°C (5.6°C to 25.1°C), 6-h temperature averaged 8.1°C (2.4°C to 15.5°C), and 20-h temperature averaged 2.4°C (0.0°C to 4.4°C). Correlations between temperature and pHu from 40 min to 165 min and from 15 h to 19 h were not significant (P > 0.05; r = −0.03 to −0.30). Correlations between temperature and pHu from 180 min to 14 h were significant (P < 0.05; r = −0.35 to −0.51). Regression models for 1 (R² = 0.49), 2 (R² = 0.63), 5 (R² = 0.72), 6 (R² = 0.81), 7 (R² = 0.84), 8 (R² = 0.88), 9 (R² = 0.91), 10 (R² = 0.92), and 13 (R² = 0.95) variable models (VARM) were generated for predicting pHu. All independent variables in the models were significant (P < 0.05) except in the 5, 6, and 13 VARM in which 1 or 2 of the independent variables tended to be significant (P < 0.10). As expected, the 1 VARM consisted of pHi, and all subsequent models did as well. The pHi is critical as a baseline before the onset of chilling to account for perimortem stress levels and allow for a better prediction of pHu. The 2 VARM also included 45-min temperature, and the 5 VARM added 50-, 55-, and 195-min temperature, with 195-min temperature remaining in subsequent models. Temperature at 45, 50, and 55 min were removed from the 6 VARM and replaced with 210-, 225-, and 345-min temperature and remaining in subsequent models. Temperature at 180 min was included in the 7 VARM but was not in subsequent models, being replaced by 80- and 165-min temperature in the 8 VARM. Temperature at 165 min remained in all subsequent models, and 80-min temperature was in all subsequent models except the 10 VARM. In the 9 VARM, 330-min temperature was added and remained in the 10 and 13 VARM. The 10 VARM added 100 min temperature and replaced 80-min with 90-min temperature. Temperatures at 90 and 100 were removed, and 45-, 75-, 80-, 95-, and 360-min temperatures were added.

Conclusion: These data indicate that loin temperature from 165 to 360 min PM is critical in the development of pHu. From a commercial perspective, these data can be used to attain desired pHu levels by precision management of the temperature decline curve.

Keywords: decline rate, pH, pork, quality, temperature

77 COMPARISON OF LONGISSIMUS LUMBORUM AND PSOAS MAJOR METMYOGLOBIN REDUCING ABILITY AND OXYGEN CONSUMPTION QUANTIFICATION APPROACHES

C. Reesman^1*, M. Denzer¹, M. Pfeiffer¹, G. Mafi¹, and R. Ramanathan¹, ¹Animal and Food Sciences, Oklahoma State University, Stillwater, Oklahoma, USA, *ranjith.ramanathan@okstate.edu

Objectives: Metmyoglobin reducing activity (MRA) and oxygen consumption (OC) are 2 important inherent biochemical properties that influence meat color. The American Meat Science Association Meat Color Guidelines describes various approaches to quantify MRA and OC. The objective of the current study was to assess and compare various combinations of MRA and OC incubation temperatures and meat surfaces related to meat color stability.

Materials and Methods: Eight USDA Low Choice short loins were collected from a beef processor 5 d postmortem. The longissimus lumborum (LL; color stable) and psoas major (PM; color labile) muscles were separated from short loins and were sliced into 1.9-cm-thick steaks on day 6 postmortem. Steaks from both muscles were placed on foam trays with absorbent pads, wrapped with polyvinyl packaging film, and placed in a simulated retail display under continuous lighting. Strip steaks were evaluated on days 0, 3, 6, and 8, and tenderloin steaks were evaluated on days 0, 2, and 4. For MRA and OC on each color analysis day, steaks were cut into half and butterflied to create 2 surfaces—one surface exposed to air during display and the other a freshly cut interior. Nitrite-induced metmyoglobin reduction was utilized for MRA analysis, whereas changes in oxymyoglobin levels of bloomed steaks following vacuum packaging were used to assess OC. For all analyses, the samples were incubated at 4°C or 37°C. Both MRA and OC were calculated as pre-incubation MRA, bloomed value, change of pre-incubation and post-incubation, and as a percentage. Hence, 12 combinations of MRA and OC values were used to assess their ability to determine these traits to follow display discoloration. Surface color readings were recorded using a HunterLab MiniScan spectrophotometer (2.5-cm diameter aperture, Illuminant A, and 10° standard observer). A split-plot design was used to assess the muscle-specific effects on MRA and OC. The data were analyzed using the PROC CORR and PROC REG options in SAS (SAS Institute Inc., Cary, NC).

Results: As expected, PM discolored faster during display than the LL. For LL, change in metmyoglobin levels pre and post incubation of surface exposed to air incubated at 37°C had the best fit with a* values (R² = 0.51). However, for PM pre-incubation metmyoglobin content of surface exposed to air during display incubated at 4°C had the best fit (R² = 0.41). For both LL and PM, bloomed values of surface exposed to air during display resulted in the best fit for OC (LL, R² = 0.76; PM, R² = 0.32). The best fit MRA and OC values for LL and PM also had the lowest coefficient of variation. The LL has more glycolytic fibers, and PM has oxidative (more mitochondria and myoglobin) fibers.

Conclusion: The LL has more glycolytic fibers, and PM has oxidative (more mitochondria and myoglobin) fibers. The current research suggests that the best fit for MRA and OC as measures of discoloration are muscle specific. Hence, using the same approach for 2 different muscle types may not provide accurate information about MRA and OC. Developing techniques to accurately predict color stability of meat during retail display is important to maximize the benefits of the postharvest process to limit losses due to discoloration.

Keywords: meat color, beef, metmyoglobin reducing activity, oxygen consumption

78 THE EFFECT OF FATTY ACID SUPPLEMENTATION IN GESTATING EWES ON CARCASS CHARACTERISTICS AND MEAT QUALITY OF LAMBS FINISHED WITH DIFFERENT LEVELS OF FEED INTAKE

Y. Wang^1*, S. Pyles¹, A. E. Relling¹, L. G. Garcia¹, and B. M. Bohrer¹, ¹Animal Sciences, The Ohio State University, Columbus, Ohio, USA, *wang.10408@buckeyemail.osu.edu

Objectives: Maternal nutrition can alter the energy metabolism, muscle development, and body composition of offspring. Previous research suggested differences in the primary feed source of maternal winter-feeding diets during mid to late gestation caused differing fat and muscle deposition in finishing lambs. However, the effect of fatty acid supplementation in late gestation ewes on carcass characteristics and meat quality of their offspring has not been investigated yet. Therefore, the objective of this study was to examine the influence of fatty acid supplementation in ewes on lamb carcass characteristics and meat quality of longissimus lumborum (LL) muscle.

Materials and Methods: Pregnant ewes (n = 24) were fed diets supplemented with 1% inclusion rate of fatty acid supplement for a 35-d period during the last trimester (day 100 to day 135) of gestation. Supplements were defined as either high in monounsaturated fatty acids (MUFA; 36.3% C18:1) or high in polyunsaturated fatty acids (PUFA; 9.18% C20:5 and 6.99% C22:6). At weaning, lambs were allocated in a 2 × 2 factorial treatment arrangement with maternal diet (MUFA or PUFA) and lamb feeding program (ad libitum or feed-restricted; 15% less than ad libitum) as main factors. Carcass data were collected and included hot carcass weight, body wall thickness, backfat thickness, LL muscle area, and an estimation of boneless trimmed retail cuts. Lamb LL (n = 24) from the right-side carcasses were collected approximately 72 h postmortem and wet aged (2°C) in vacuum packages for an additional 4 d (total of 7 d postmortem aging). After the aging period, each LL muscle was fabricated into two 6.35-cm length sections, vacuum packaged, and randomly allotted to an internal endpoint cooking temperature of either 63°C or 71°C using a water bath before being evaluated for instrumental color (Minolta spectrophotometer) and tenderness (TA-XT texture analyzer equipped with a Meullenet-Owen Razor Shear [MORS] fixture). The remaining section was used for uncooked instrumental color, muscle pH, and proximate composition (intramuscular fat percentage) analysis. Carcass characteristic and meat quality results were analyzed using PROC MIXED of SAS (SAS Institute Inc., Cary, NC), and differences among the means were performed using the least significant differences test at the 5% level.

Results: Hot carcass weight, body wall thickness, LL muscle area, estimation for boneless trimmed retail cuts, pH, instrumental color, tenderness, and intramuscular fat percentage were not influenced (P ≥ 0.10) by maternal fatty acid supplementation, finishing lamb feed intake, or their interaction (Table 1). Nonetheless, an interaction (P < 0.05) between maternal fatty acid supplementation and finishing lamb feed intake was observed for backfat thickness, with lambs from ewes with MUFA supplementation assigned to restricted feeding and lambs from ewes with PUFA supplementation assigned to ad libitum feeding exhibiting greater (P < 0.05) backfat thickness when compared with lambs from ewes with PUFA supplementation assigned to restricted feeding.

Conclusion: Overall, the observed interaction between maternal nutrition and finishing lamb feed intake altered backfat thickness, yet meat quality parameters were not influenced.

Keywords: carcass characteristics, fatty acid, fetal programing, lamb quality, maternal diet

79 MODIFIED ALGORITHMS TO QUANTIFY SUB-SURFACE MYOGLOBIN FORMS USING NEAR-INFRARED DIFFUSE REFLECTANCE SPECTROSCOPY

D. Piao¹, M. L. Denzer^2*, G. G. Mafi², and R. Ramanathan², ¹School of Electrical and Computer Engineering and ²Department of Animal and Food Sciences, Oklahoma State University, Stillwater, Oklahoma, USA, *mdenzer@ostatemail.okstate.edu

Objectives: The proportion of myoglobin forms on surface and sub-surface of meat dictates the visual appearance. Hence, quantification of myoglobin forms is of interest to researchers and industry. Techniques without sample preparation, rapid, and accurate are ideal considerations while designing methods to determine myoglobin forms. Reflectance spectrophotometry, the current standard of color evaluation in meat, assesses metmyoglobin near the surface. By configuring the illumination and collection of broad-band light sensitive to myoglobin absorption to probe deeper meat, sub-surface myoglobin formation can be measured. Commercially available near-infrared (NIR) based spectrophotometry techniques are designed to quantify oxy- and deoxymyoglobin as metmyoglobin content is physiologically negligible. Here, we discuss a novel algorithm to quantify metmyoglobin content using NIR-based diffuse reflectance spectroscopy.

Materials and Methods: Beef longissimus lumborum muscles were collected from a commercial processor day 5 postmortem (n = 8 replications). Steaks were cut, packaged in polyvinyl chloride film, and displayed under simulated retail display cases (Philips Neutral White LED lamps [Andover, MA]; color rendering index = 82; color temperature = 3,000°K) for 8 d. Oxymyoglobin (OxyMb), deoxymyoglobin, and metmyoglobin content on beef longissimus lumborum muscles were determined daily for 8 d using a HunterLab MiniScan spectrophotometer and in-house developed NIR-DRS. Daily changes in subsurface myoglobin redox states at a probing depth of approximately 1.5 mm were evaluated using NIR-DRS and compared with surface color assessed by HunterLab MiniScan spectrophotometer (a 2.5-cm-diameter aperture, illuminant A, and 10° standard observer). A custom mathematical model programmed in MATLAB was used to assess deoxymyoglobin, OxyMb, and metmyoglobin. The model utilized approximately 18 wavelengths spanning 480 to 650 nm to quantify myoglobin forms.

Results: Both HunterLab MiniScan and NIR-DRS measurements revealed that metmyoglobin increased steadily over the duration of display, and both demonstrated a high correlation (R² = 0.91) between the 2 methods. NIR-DRS revealed the OxyMb to have decreased steadily over the period of display. However, the HunterLab MiniScan spectrophotometer indicated a much later onset of the apparent decrease of OxyMb than the NIR-DRS reading, resulting in a moderate correlation (R² = 0.64) between the 2 methods. No correlation was found between the 2 methods regarding the changes of deoxymyoglobin over the duration of the display.

Conclusion: By probing deeper muscle using myoglobin-sensitive spectra than the conventional reflectance spectrophotometry, the newly developed NIR-DRS approach has potential as an alternative method for color assessment in postrigor skeletal muscle.

Keywords: diffuse reflectance spectroscopy, meat color, myoglobin, near infrared, reflecto-spectrophotometry

80 COMPARISON OF MYOGLOBIN QUANTIFICATION METHODS

N. Hawkins¹, M. L. Denzer^1*, G. G. Mafi¹, M. Pfeiffer¹, M. C. Hunt², R. Mancini³, and R. Ramanathan¹, ¹Department of Animal and Food Sciences, Oklahoma State University, Stillwater, Oklahoma, USA; ²Department of Animal and Industry, Kansas State University, Manhattan, Kansas, USA; ³Department of Animal Science, University of Connecticut, Storrs, Connecticut, USA, *mdenzer@ostatemail.okstate.edu

Objectives: Quantification of meat color changes is important to understand discoloration. Various approaches are reported in the literature to quantify myoglobin forms using both destructive and nondestructive approaches. In the sarcoplasmic extraction procedure, samples at specific days of storage are homogenized in buffer, and the supernatant is used to determine myoglobin forms. In Krzywick’s method, reflectance values are converted to absorbance and inserted in appropriate equations to determine myoglobin forms. The American Meat Science Association Meat Color Guidelines describes the use of K/S ratios at isobestic points to quantify myoglobin forms. The K/S ratio takes into account absorption (K) and scattering (S) components of meat. However, limited studies have compared different methods to quantify deoxymyoglobin (DeoxyMb), oxymyoglobin (OxyMb), and metmyoglobin (MetMb). The objective of the study was to compare 3 myoglobin quantification methods—sarcoplasmic extraction, Krzywick’s method, and K/S methodology.

Materials and Methods: Six USDA Select beef strip loins from a commercial processing plant were cut into 1.9-cm-thick steaks, placed onto foam trays with absorbent pads, and over-wrapped with a polyvinyl chloride film. The steaks were displayed on a simulated retail display case for 8 d. Three steaks from each loin were also utilized to prepare 100% standards of DeoxyMb, OxyMb, and MetMb using the K/S method. Myoglobin forms were determined using 3 methods every 48 h of display. The data were analyzed using regression, correlation, and coefficient of variation options in SAS. The data for each myoglobin form were analyzed separately.

Results: Krzywicki’s method had a lower coefficient variation (P < 0.05) for OxyMb compared with the sarcoplasmic and K/S methods. However, the range of OxyMb values for Krzywick’s method was narrow compared with sarcoplasmic and K/S methods. The coefficient of variation for the sarcoplasmic method was greater (P < 0.05) for MetMb compared with the other 2 methods. Tissue homogenization steps in sarcoplasmic method can promote more oxidative changes. The coefficient of variation was greater (P < 0.05) when sarcoplasmic and K/S methods were used to quantify DeoxyMb.

Conclusion: In general, the K/S method captured a great range of OxyMb and MetMb changes than did Krzywick’s and sarcoplasmic extraction methods. Developing techniques to accurately measure myoglobin forms are important to understand meat color changes.

Keywords: meat color, myoglobin, sarcoplasm

81 CHARACTERIZING CARCASS CONFORMATION, QUALITY ATTRIBUTES, AND MUSCLE FIBER PROPERTIES OF BEEF × DAIRY CROSSBRED CATTLE

J. L. Frink¹, C. A. Mairena^1*, B. A. Foraker¹, L. K. Fuerniss¹, S. T. Howard², J. F. Legako¹, B. J. Johnson¹, M. F. Miller¹, and D. R. Woerner¹, ¹Animal and Food Science, Texas Tech University, Lubbock, Texas, USA; ²Process Improvement Lead, Cargill, Wichita, Kansas, USA, *carlos.mairena@ttu.edu

Objectives: The increase in the number of crossbred cattle resulting from the mating of conventional beef-type (CB) bulls and dairy cows has elevated the need for research pertaining to beef resulting from this scenario. The objective of this study was to characterize this changing segment of the US fed beef supply on the basis of meat quality and immunohistochemical properties of beef resulting from beef × dairy (BD) crossbred cattle relative to CB and dairy-type (DT) cattle.

Materials and Methods: At 3 different commercial beef packing facilities, BD, CB, and DT carcasses (N = 560) were selected to equally represent USDA Prime, Upper 2/3 Choice, Choice, and Select quality grades. Following carcass selection, strip loin sections (5 cm thick) were collected from both carcass sides and stored at (2°C to 4°C) in the dark for 14 d. At the same time, samples from the longissimus lumborum were collected for immunohistochemical analysis (n = 113). The immunohistochemical samples were cut parallel to muscle fibers and immediately embedded in clear section compound and frozen using dry ice and 2-methyl-butane and stored at −80°C. Muscle fiber cross-sectional area and myosin heavy chain isoform were determined by cutting 10-μm-thick cross-sections perpendicular to the muscle fibers at −19°C. Aged strip loin sections designated for quality analysis were fabricated into four 2.54-cm steaks, vacuum packaged and stored at −20°C. At the time of fabrication, steaks were randomly assigned to shear force, trained sensory, consumer sensory, or retail display. Only samples from USDA Choice carcasses were evaluated for retail display and color performance. Data were analyzed as a completely randomized experiment with a 3 × 4 factorial arrangement. Cattle type, USDA Quality Grade, and their interaction (when appropriate) were included as fixed effects.

Results: All evaluated carcass traits were impacted by cattle type (P < 0.01). BD carcasses were intermediate to CB and DT in fat thickness, ribeye area, and carcass length. Longissimus samples from BD carcasses had the greatest proportion of myosin heavy chain-IIA fibers (P ≤ 0.01) and the largest mean cross-sectional area (P ≤ 0.05). Cattle type impacted pH, trained color panel attributes, L* and a* values, and shear force measurements (P < 0.01). Trained sensory analysis indicated that tenderness, juiciness, sour, metallic, fat-like, buttery, liver and oxidized attributes were affected by cattle type (P < 0.01). Consumers identified a difference in tenderness among cattle types (P < 0.01).

Conclusion: Crossbreeding beef sires and dairy cows will continue to change the dairy influenced portion of the US fed beef supply. Beef from crossbred beef × dairy cattle can be expected to perform with superiority in flavor and tenderness compared with CB, without shelf life concerns at retail display associated with beef from Holsteins. Marketing programs founded on eating quality should consider inclusion of beef from BD crossbreds.

Keywords: beef, color, dairy, fiber type, sensory

82 MEASURING THE REPEATABILITY AND ACCURACY OF RAPID EVAPORATIVE IONIZATION MASS SPECTROMETRY (REIMS) USING PORK AND MULTIPLE PREDICTION TECHNIQUES

M. D. Clancy¹, J. C. Sarchet^1*, E. R. Bechtold¹, D. A. Gredell², J. F. Legako¹, J. C. Brooks¹, M. F. Miller¹, and D. R. Woerner¹, ¹Animal and Food Science, Texas Tech University, Lubbock, Texas, USA; ²Independent Contractor, Kansas City, Missouri, USA, *chandler.sarchet@ttu.edu

Objectives: Rapid evaporative ionization mass spectrometry (REIMS) has shown potential in the meat and food industries to identify food fraud, classify samples, and potentially predict quality attributes. While recent research has shown REIMS to be a capable method of sample differentiation, the reliability and repeatability of the machine has yet to be fully examined. In this study, the repeatability and prediction accuracy of REIMS for identifying homogenized pork loin (N = 360), technician (n = 3), and day of analysis (n = 3) was explored.

Materials and Methods: The M. longissimus thoracis et lumborum (LTL) muscle was isolated from 3 boneless pork loins purchased from a local club store on the same day, and efforts were made to select pork loins originated from different animals, based upon visual assessments. For each pork loin, the LTL was completely denuded, flash frozen in liquid nitrogen, and pulverized/homogenized. Five-gram aliquots of the homogenous mixture were placed into multi-well trays (12 wells each) in a random order. Samples were kept frozen (−80°C) until further analysis. Trays were randomly and equally distributed across technician (n = 3) and day of analysis (n = 3). Homogenate mixtures representing the individual pork loins were analyzed for proximate analysis. Each day, samples were thawed in a refrigerator prior to being analyzed (12–18 h), and spectra were acquired from the individual samples using a Synapt G2-0Si Q-TOF equipped with REIMS and an iKnife sampling device in negative resolution mode. This study was analyzed as a completely randomized design wherein a repeated measure analysis of variance day and technician served as fixed effects and tray served as a random effect. Principal component analysis was used as an explorative technique for determination of metabolomic differences between pork loins. Lastly, a multivariate approach, quadratic discriminant analysis (QDA), was used for determining classification of pork loin ID, technician, and REIMS day.

Results: Proximate analysis indicated no significant differences in composition between pork loins (P > 0.05); however, using QDA and the data acquired from the REIMS spectra, the model was able to identify the correct pork loin with a 71.67% accuracy. Additionally, a QDA model was able to identify the day of sample acquisition with an 80.8% accuracy, indicating a day effect in the data collection procedures. Conversely, the QDA model was able to correctly identify the technician 36% of the time, indicating that operator and/or technician had a minimal effect on data acquisition over the 3 d of analysis. When spectra were analyzed using a principal component analysis, peaks at 279.25 m/z (linoleic acid) and 281.25 m/z (oleic acid) were determined to be the predominant drivers of variability between individual loin samples.

Conclusion: In conclusion, REIMS displayed its ability to accurately separate highly similar samples regardless of technician. However, an unidentified day effect could potentially affect results over an extended testing interval. Further research into the contributors to the day effect, as well as the machine’s tolerance to this effect, is warranted.

Keywords: machine learning, mass spectrometry, metabolomics, pork, rapid evaporative ionization mass spectrometry

83 DIVERGENT PHENOTYPES OF CROSSBRED BEEF × DAIRY CATTLE MINIMALLY INFLUENCE EATING QUALITY AND CARCASS PERFORMANCE

B. A. Foraker^1*, B. J. Johnson¹, J. F. Legako¹, J. C. Brooks¹, R. J. Rathmann¹, M. F. Miller¹, and D. R. Woerner¹, ¹Department of Animal & Food Sciences, Texas Tech University, Lubbock, Texas, USA, *blake.foraker@ttu.edu

Objectives: Claims of considerable visual variation in crossbred beef × dairy cattle, combined with negative associations of dairy influence, have produced questions about their inclusion into quality-driven branded programs. Varying expressions of visual phenotype in crossbred cattle with equal Bos indicus influence have previously impacted eating quality. The present study evaluated effects of visual phenotype expression in crossbred beef × dairy cattle on carcass performance and eating quality.

Materials and Methods: A panel of 3 expert evaluators assessed a total of 615 crossbred (Angus or Simmental × Angus bulls mated to Holstein cows) beef × dairy calves from 9 commercial feedlot pens for muscling and frame size. Visual assessments were used to subset each pen and categorize cattle into 4 phenotype groups (n = 82 to 84 cattle per group). Carcass data were collected, and strip loin steaks from each animal were evaluated for dimensionality, shear force, trained sensory performance (tenderness, juiciness, and flavor notes), retail color display, fatty acid composition, and myosin heavy chain isoforms. Data analyses tested for fixed effect of phenotype group and accounted for random effect of pen (block).

Results: Although visual appearance (muscling and frame size)—by design—was distinctly different (P < 0.05) among phenotype groups of beef × dairy crossbreds evaluated in this study, few (if any) differences (P < 0.05) were noted in trained sensory performance, shear force, steak dimensionality, fatty acid composition, and retail color display. Crossbreds that were more dairy-like in appearance exhibited a lesser (P < 0.05) proportion of glycolytic muscle fibers, suggesting opportunity for more aggressive use of growth technologies, without detriment to eating quality. Beef-like crossbreds exhibited shorter (P < 0.05) carcasses with greater (P < 0.05) round muscling conformation than dairy-like crossbreds—even when carcass weights and ribeye areas did not differ (P ≥ 0.28)—indicating a shift in distribution of muscularity.

Conclusion: Live expression of dairy or beef character in crossbred beef × dairy cattle minimally contributed to differences in carcass performance or eating quality. Additional research is needed to understand carcass yield and muscle fiber type composition of beef × dairy crossbreds. Nonetheless, efforts to exploit complementarity of beef genetics in terminal beef × dairy systems cannot be expected to negate consistency in eating quality of resulting product.

Keywords: beef, dairy, eating quality, fiber type, phenotype

84 OBSERVED AND DERIVED MEASUREMENTS OF BEEF CARCASS CHILLING RATE: THEIR RELATION TO EACH OTHER AND CARCASS TRAITS

M. Fevold^1* and R. Maddock¹, ¹Animal Sciences, North Dakota State University, Fargo, North Dakota, USA, *michaella.fevold@ndus.edu

Objectives: The objectives of this research were to evaluate methods of reporting chilling rates of beef carcasses, including observed and derived measurements, and how these measurements relate to each other and carcass traits. The knowledge obtained from the aforementioned objectives may indicate what measures of chilling rates are best used when evaluating beef carcass chilling.

Materials and Methods: Beef carcasses (n = 53) representing various hot carcass weights were randomly selected over 5 nonconsecutive days at a commercial beef processing facility after harvest and immediately before entering the chill cooler. Carcasses were outfitted with a data logger that recorded temperature every 15 min for 24 h. One temperature probe was inserted into the longissimus thoracis (LT) at approximately the 6th rib, and the other temperature probe was inserted into the direct center of the semimembranosus (SM). After a 24-h chill, carcass data, including hot carcass weight, 12th rib fat thickness, ribeye area, kidney pelvic and heart fat percentage, and marbling score, were collected by trained personnel. After chill data retrieval, derived measures of chilling rate were calculated, including determining the total area under the chilling curve (AUC) for the 0–6 h and 0–24 h chill time windows via the trapezoidal method with temperature as the y-axis and time as the x-axis. Additionally, the average slope of the temperature decline curve was calculated. Pearson correlations coefficients among carcass temperatures at various times (0, 4, 8, 12, 16, 20, and 24 h), derived measures of chilling rate, and carcass traits were found using the PROC CORR procedure of SAS (version 9.4, SAS Institute Inc., Cary, NC).

Results: In both the LT and SM, derived slope of the temperature decline curve was not significantly correlated with other temperature measures (r ≤ 0.42, P ≥ 0.08). In the LT and SM, 8 h and 12 h timepoints were significantly correlated with other temperatures (0, 4, 6, 8, 12, 16, 20, 24 h, AUC 6 h, and AUC 24 h) (r ≥ 0.54, P ≤ 0.0001). In the LT, 20 and 24 h temperature measures were significantly correlated to 12th rib back fat thickness (r = 0.50, P = 0.0001, r = 0.52, P ≤ 0.0001, respectively). Conversely, in the SM, 12, 16, 20, and 24 h temperature measures were significantly correlated to hot carcass weight (r ≥ 0.37, P ≤ 0.0089).

Conclusion: Our results indicate that using raw chilling rate data, as well derived AUC measures, is appropriate to evaluate beef carcass chilling rates. Additionally, our results indicate that the 8 and 12 h timepoints have the highest correlations with other temperature decline data; however, other timepoints were also significantly correlated and could be used. Furthermore, our results indicate for the LT, 12th rib fat thickness is more highly correlated to temperature decline than other carcass measurements. Conversely, for the SM, hot carcass weight is more highly correlated to temperature decline than other carcass measurements. Further research is needed to continue to understand how best to evaluate beef carcass chilling rate data, as well as how various carcass measurements may affect overall beef carcass chilling rates.

Keywords: beef chill, carcass characteristics

85 QUALITY AND CARCASS CHARACTERISTICS OF MEAT RABBITS FED HEMPSEED MEAL

A. Wright^1*, K. J. Jacobson¹, J. P. Muir², W. B. Smith¹, L. A. Kinman¹, and A. M. Cassens¹, ¹Animal Science and Veterinary Technology and ²Texas A&M AgriLife Research, Tarleton State University, Stephenville, Texas, USA, *amber.wright@go.tarleton.edu

Objectives: Industrial hemp has been used in the US to make fiber from stalks, food from hempseed, and oil from flowers. After oil extraction, hempseed meal (HSM) is a high-protein byproduct that can potentially be used as a livestock feed source. The objective of this study was to evaluate the carcass characteristics of meat rabbits supplemented with HSM as a protein replacement in the ration.

Materials and Methods: Four rations were formulated and fed to rabbits containing varying inclusion rates of HSM: 0% (Control; n = 8), 25% (n = 8), 50% (n = 8), and 75% (n = 7) replacement of protein source in a pelleted feed. Rabbits were fed for 35 d and harvested at Tarleton State University Rabbitry following Institutional Animal Care and Use Committee (IACUC) guidelines (AUP 02-002-2021). Live weight was taken 12 h prior to slaughter, and hot carcass weights (HCW) were collected immediately after slaughter. Carcass measurements were taken while suspended by the Achilles on leg hooks measuring 20 cm wide. Length of leg was measured from the calcaneal tuberosity to the posterior edge of the ilium. Length of body was measured from the posterior edge of the ilium to the anterior edge of the first rib. Length of loin was measured from the anterior edge of the ilium to the posterior edge of the last rib. Width of leg and width of shoulder was measured from the ventral edge of the flank and elbow pockets, respectively. Muscle pH was taken 0 and 24 h postmortem in the leg, loin, and shoulder. Rabbits were fabricated, and individual weights of lean, fat, and bone were collected. Percentage carcass composition was determined by dividing the lean, fat, and bone by the HCW. Data were analyzed as a generalized complete block design using the GLIMMIX model in SAS version 9.4 (SAS Institute Inc., Cary, NC). Statistical significance was set at P ≤ 0.05.

Results: Rabbits fed 75% HSM had a lower (P < 0.05) final live and HCW compared with control, 25% HSM, and 50% HSM. Rabbits fed 75% HSM had shorter carcasses (P < 0.05) compared with all other treatments. Rabbits supplemented with 50% HSM had a wider leg (P < 0.05) compared with 75% HSM. Also, there was no difference (P > 0.05) in leg width between the control, 25% HSM, and 50% HSM. Rabbits fed the control had a longer loin (P < 0.05) compared with 75% HSM. Additionally, there was no difference (P > 0.05) in loin length between control, 25% HSM, and 50% HSM. There was no difference (P > 0.05) for the length of leg and width of shoulder between treatments. At 0 h postmortem, there was no difference (P > 0.05) in muscle pH between treatments. However, rabbits fed 75% HSM had the highest (P < 0.05) pH 24 h postmortem. Lastly, there was no difference (P > 0.05) between treatments in percentage lean, fat, or bone in the carcass composition analysis.

Conclusion: Rabbits fed HSM at 25% or 50% of the protein source resulted in no changes in carcass length, composition, and quality as compared with the control and may be an advantageous supplement to the livestock industry. However, rabbits fed a 75% HSM ration resulted in lighter live and carcass weights while producing a shorter carcass with shorter loins, narrower legs, and a higher overall pH 24 h postmortem and should not be considered as a replacement level.

Keywords: carcass composition, hempseed meal, quality, rabbit

86 USING RAPID EVAPORATIVE IONIZATION MASS SPECTROMETRY (REIMS) AS A NOVEL, MINIMALLY INVASIVE, REAL-TIME METHOD FOR CHARACTERIZATION OF METABOLIC VARIATION CONTRIBUTING TO FLAVOR, TENDERNESS, AND COLOR STABILITY OF BEEF

K. N. Frazier^1*, T. M. Horton¹, T. L. Wheeler², S. D. Shackelford², D. A. King², J. F. Legako¹, J. C. Brooks¹, M. F. Miller¹, and D. R. Woerner¹, ¹Animal and Food Sciences, Texas Tech University, Lubbock, Texas, USA; ²USDA-ARS, US Meat Animal Research Center, Clay Center, Nebraska, USA, *kenley.frazier@ttu.edu

Objectives: Rapid evaporative ionization mass spectrometry (REIMS) is relatively new technology that has emerged in both human and food science. REIMS, a new method of collecting data from intact biological tissue, allows for little to no sample preparation and very fast sampling times. Online, rapid detection of metabolites that contribute to differences responsible for meat quality attributes has major implications. This study evaluated the ability of REIMS to classify beef based on palatability and color stability.

Materials and Methods: Samples were obtained from a previous study in which USDA Choice strip loin steaks (N = 191) were selected for variation in predicted slice shear force, objective color measurements, and trained sensory evaluation of flavor. Metabolomic profiles (50 to 1,200 m/z) were generated by REIMS in negative resolution mode. Individual samples were classified into performance groups of palatability and color stability using principal component analysis and k-means clustering. Discriminant and quadratic function analyses classifications evaluated the accuracy of the predictive model.

Results: REIMS correctly characterized 96.34% of samples sorted on objective color measurements, using 2 discriminant functions explaining 97.44% in discriminant function 1 (P < 0.001) and 2.45% in discriminant function 2 (P < 0.001) of variation in the dataset. Performance groups were distinctly different in objective color measurements (P ≤ 0.01). However, samples had limitations in variability of tenderness and sensory attributes, restricting the capability of REIMS to differentiate between specified performance groups at a relatively low accuracy of 47.64%.

Conclusion: Due to the variation in color and color stability, REIMS had the ability to identify color differences with a high level of accuracy. Additionally, with greater variability and a larger sample size, REIMS shows significant promise in detecting flavor and tenderness differences as well as color stability performance groups of beef.

Keywords: beef, machine learning, meat quality, rapid evaporative ionization mass spectrometry, sensory

87 PRELIMINARY ASSESMENT OF THE MEAT IMAGING JAPAN (MIJ) BEEF GRADING SMARTPHONE APPLICATION AS IT COMPARES TO A CURRENT USDA VALIDATED BEEF GRADING CAMERA VISION SYSTEM

J. Lancaster^1*, M. Colle¹, B. Epperson¹, J. Smart¹, K. Oliver¹, H. Komine², A. Kano², Y. Sakaguchi², K. Kuchida², D. Cicale³, and P. Bass¹, ¹Animal and Veterinary Science, University of Idaho, Moscow, Idaho, USA; ²Japan, Meat Image, Obihiro, Japan; ³United States, Meat Image, Hackelburg, USA, *lanc6314@vandals.uidaho.edu

Objectives: Camera vision beef grading systems can be cost prohibitive to smaller beef processers, which results in limited advanced technology grading capabilities. The objective of this study was to compare an alternative beef carcass grading technology with a commercially available USDA-approved beef grading camera (VBG2000, E+V Technology).

Materials and Methods: Beef carcasses (n = 910), representing marbling standards from USDA Select, Choice, and Prime in youthful, commercially raised beef cattle served as the experimental units. All beef carcasses utilized were evaluated in a large-scale commercial beef harvesting facility and assessed online in the grading cooler. Data were collected using the Meat Imaging Japan (MIJ) beef grading application software and camera cradle accessory lighting kit with a Google Pixel 4 XL platform. The MIJ camera data were collected in unison with that of a commercially available, USDA-approved, online instrument grading technology (VBG2000, E+V Technology GmbH & Co. KG, Oranienburg, Germany). Carcass grading information was analyzed using Pearson correlation analyses.

Results: The marbling scores obtained by the MIJ camera observations had a strong correlation to the currently validated beef grading vision system (r = 0.71; P < 0.01). The ribeye areas of the evaluated carcasses ranged from 61.87 cm² to 127.55 cm². The ribeye areas observed by the MIJ camera were moderately correlated to the currently validated beef grading vision system (r = 0.56; P < 0.01).

Conclusion: The initial validation of an alternative beef grading system suggests an opportunity to pursue additional validation for further use in USDA processing facilities. Ultimate utilization of the MIJ camera vision system will allow for more beef producers and processors to capture objective beef carcass data across a wider range of processing facilities.

Keywords: beef, camera grading, ribeye size

88 NOVEL NEAR-INFRARED–BASED NEEDLE PROBE TO ASSESS INTERIOR MEAT COLOR

M. Denzer^1*, D. Piao², M. Pfeiffer¹, G. G. Mafi¹, and R. Ramanathan¹, ¹Department of Animal and Food Sciences and ²School of Electrical and Computer Engineering, Oklahoma State University, Stillwater, Oklahoma, USA, *mdenzer@ostatemail.okstate.edu

Objectives: As consumers prefer a bright cherry-red color of steaks, discoloration leads to less consumer acceptance. Metmyoglobin formation results in discoloration, and this process starts at the interior of steaks and spreads to the surface. Researchers utilize surface color measurements to study meat color chemistry. Limited surface-based studies have evaluated interior color changes to understand meat discoloration. Here, we discuss a novel near-infrared (NIR)–based probe to study localized interior meat color. The objective was to use a needle-probe–enabled NIR diffuse reflectance spectroscopy (DRS) to evaluate localized interior color changes in psoas major steaks during retail display.

Materials and Methods: Six psoas major steaks from different loins were collected from a regional processing facility and transported on ice to Oklahoma State University. The steaks were cut, packaged in polyvinyl chloride overwrap, and placed in a simulated retail display for 5 d. During retail display, surface color was evaluated every day in triplicate using a HunterLab MiniScan Spectrophotometer to quantify changes in surface color of the steaks. Subsurface localized myoglobin forms at depths of 1 mm to 6 mm. In this study, myoglobin forms were evaluated daily at 1-mm intervals using the needle-probe NIR-DRS. The needle probe consisted of two 320-μm fibers epoxied side by side for strain-confined positioning within a 17-gauge spinal needle. An applicator was developed to place the needle probe at 6 positions spaced laterally at an interval of 10 mm and inserted at 6 depths at increments of 1 mm. A custom mathematical model programmed in MATLAB was used to assess deoxy-, oxy-, and metmyoglobin from the needle-probe data. A HunterLab MiniScan spectrophotometer was also used to record surface L*a*b*. Surface color data measured by HunterLab MiniScan spectrophotometer were analyzed using PROC Mixed Procedure of SAS (SAS Institute Inc., Cary, NC).

Results: As retail time increased, the steaks were darker (decreased in L* values) and less red (decrease in a* and chroma values, P < 0.05). The NIR-DRS needle probe revealed differences in myoglobin form at various depths within each steak and during retail display for each steak at the same depth. The needle probe revealed that all steaks at day 0 had greater deoxymyoglobin content at approximately 3 mm (75.64%) than the shallower layer (62.14%), which was consistent with lesser oxygen to bind with myoglobin at greater depth than at the surface. The needle probe also revealed that oxymyoglobin content below 2 mm depth increased throughout storage time in all steaks. The results indicated deeper penetration of oxygenation over time. Metmyoglobin formation increased at all depths during retail time. At 6 mm, metmyoglobin was at 0.19% at day 0 and increased steadily to 9.21% by day 4 of retail display. A similar trend in metmyoglobin formation was reported in the shallower layers paralleling with the decline in a* values through retail display.

Conclusion: In conclusion, an in-house–developed NIR-DRS needle probe and algorithm provided information about localized internal color changes in postrigor skeletal muscle. Localized characterization of internal color changes helps to understand muscle-specific, packaging, and aging-related color changes. In addition, determining interior metmyoglobin content helps to predict discoloration before it is visually seen on surface.

Keywords: diffuse reflectance spectroscopy, meat color, myoglobin, near infrared, reflecto-spectrophotometry

89 EVALUATING THE ABILITY OF RAPID EVAPORATIVE IONIZATION MASS SPECTROMETRY (REIMS) TO QUANTIFY COMPOUNDS RELATED TO BEEF QUALITY

T. M. Horton^1*, J. F. Legako¹, D. A. Gredell², B. A. Foraker¹, J. C. Brooks¹, D. A. King³, S. D. Shackelford³, T. L. Wheeler³, M. F. Miller¹, and D. R. Woerner¹, ¹Animal and Food Sciences, Texas Tech University, Lubbock, Texas, USA; ²-, Independent Consultant, Kansas City, Missouri, USA; ³USDA-ARS, US Meat Animal Research Center, Clay Center, Nebraska, USA, *taylor.horton@ttu.edu

Objectives: Though gas chromatography (GC) methods have long served as the standard for quantifying compositional elements in meat products, they require extensive sample preparation, are very costly, and do not produce real-time results. Conversely, rapid evaporative ionization mass spectrometry (REIMS) produces metabolomic profiles comparable to GC methods in real time and does not require sample preparation. This study evaluated the ability of REIMS to characterize compounds related to beef quality at time of grading.

Materials and Methods: Strip loin steaks were collected at the time of grading (4 d postmortem) from A maturity carcasses of classifications: USDA Prime, Upper 2/3 Choice, Low Choice, USDA Select, Wagyu, Grassfed, and Dark Cutter. Metabolomic profiles measured by REIMS in negative sensitivity mode on intact steaks were compared with compositional profiles—amino acids, fatty acids, and volatile compounds—measured by conventional GC methods on steak homogenates. Using discriminant function analysis, metabolomic profiles from REIMS and GC methods were separately evaluated to determine their accuracy in characterizing samples into carcass classifications. Partial least squares regression models using trained-test validation evaluated the ability of REIMS to predict amounts of 100 different compounds measured by GC.

Results: A discriminant function analysis demonstrated comparable ability of REIMS to achieve a similar result as GC for determining carcass classification (as mentioned previously) with 94% and 90% variation explained and 33% versus 43% prediction accuracy, respectively. However, a partial least squares analysis using REIMS spectra (50–1,500 m/z) from a 4-d sample was unsuccessful in predicting quantities of individual compounds, in reference to the same compounds quantified by GC methods (R² ≤ 0.27).

Conclusion: There is significant work to be done for the development of REIMS procedures to identify and quantify individual compounds in tissue samples, which includes new data preprocessing methods and more targeted variable selection for models, as well as implementation of internal standards and consultation of a mass spectrometry library.

Keywords: beef, gas chromatography, mass spectrometry, quality, rapid evaporative ionization mass spectrometry

90 REAL-TIME PREDICTION OF PORK LOIN QUALITY AND PALATABILITY BY A METABOLOMIC PROFILE COLLECTED BY RAPID EVAPORATIVE IONIZATION MASS SPECTROMETRY

M. D. Clancy^1*, D. A. Gredell², T. M. Horton¹, B. A. Foraker¹, E. R. Bechtold¹, K. Underwood³, B. Fields⁴, M. F. Miller¹, J. F. Legako¹, and D. R. Woerner¹, ¹Animal and Food Sciences and ²Independent Contractor, Texas Tech University, Lubbock, Texas, USA; ³Animal Sciences, South Dakota State University, Brookings, South Dakota, USA; ⁴Manager, Applied Meat Science, PIC, Hendersonville, Tennessee, USA, *meghanclancy@standardmeat.com

Objectives: It has been suggested that the pork industry implement a quality grading system, using factors such as marbling and color score, to sort pork carcasses into meaningful groups like palatability ratings (HT1). Rapid evaporative ionization mass spectrometry (REIMS) has shown promise to accurately predict sensory attributes and quality categories of pork chops using 2 prediction model techniques, principal component linear discriminant analysis (PC-LDA) and linear discriminant analysis with an F-test applied (F-test-LDA).

Materials and Methods: Duroc × White line crossbred barrows (n = 203) and gilts (n = 197), representing different sire lines, were harvested at the same facility 3 consecutive weeks, at approximately 6 mo of age, and paired boneless center-cut pork loins (N = 400) were collected. South Dakota State University collected yield measurements using the BioQ Scanner and reported a numerical color score (Pork Color Standards, National Pork Board, 1999), marbling score, Minolta L*, a*, and b*, pH, and Warner-Bratzler shear force values. Metabolomic profiles were obtained from a raw, intact pork chop using a Synapt G2 Si Q-TOF, coupled with a REIMS ionization source and an iKnife sampling device in negative resolution mode. A paired pork chop was evaluated by trained sensory panelists for tenderness, juiciness, and flavor attributes. Each sensory or quality attribute was transformed from a continuous value to a categorical response—low, medium, high—based on distance from the respective mean. Then, PC-LDA and F-test-LDA models used REIMS to classify individual samples into low, medium, and high categories.

Results: F-test-LDA models presented accuracy classification percentages of greater than 95% for marbling scores, color scores, and tenderness. Additionally, sensory attributes were classified correctly with high accuracy: pork flavor intensity: 97%; boar taint: 89%; oxidized: 86%; and other sensory flavors: >94% of samples.

Conclusion: These modeling techniques coupled with REIMS show promise as part of the implementation of a pork quality grading system. Further research of REIMS metabolomic profiles, along with predictive models, is warranted for understanding REIMS full capabilities in predicting palatability.

Keywords: metabolomics, pork grading system, pork palatability, pork quality, rapid evaporative ionization mass spectrometry

91 EFFECTS OF DRY AND WET AGING ON SENSORY ATTRIBUTES, TENDERNESS, AND VOLATILE PROFILE OF USDA SELECT STRIP LOINS

A. S. De Mello^1*, A. Cavender¹, F. Giotto¹, and M. Teglas¹, ¹Agriculture, Veterinary, and Rangeland Sciences, University of Nevada, Reno, Nevada, USA, *ademello@unr.edu

Objectives: The study objective was to evaluate the effects of dry and wet aging on sensory attributes, Warner-Bratzler shear force (WBSF), and volatile profile of USDA Select short loins aged 21 and 80 d.

Materials and Methods: Thirty-two USDA Select short loins were arranged to a 2 × 2 factorial to evaluate the effects of aging method (dry and wet), length (21 and 80 d postmortem), and their interaction. Samples were dry aged at 2°C ± 2°C with 80%–85% of relative humidity and air speed of 2 m/s. Wet-aged samples were stored under vacuum at same temperature. After aging, strip steaks were fabricated, and sensory analysis was conducted with 8 panelists. Tenderloins were tested separately. For volatiles, steaks were analyzed in 3 zones, dorsal, intermediate, and ventral portions (2 × 2 × 3 factorial). Volatiles were captured using SPME fibers that were desorbed on a GCMS (Shimadzu Co., Kyoto, Japan). A texture analyzer was used to determine WBSF (Food Technology Co., Sterling, VA). Data were analyzed as a CRD using PROC GLIMMIX, PROC FREQ, and PROC CORR of SAS (SAS Institute Inc., Cary, NC). The level of significance was P ≤ 0.05.

Results: No effects of aging length or method were observed on WBSF, tenderness, juiciness, and connective tissue. Panelists scored samples aged 80 d with higher off-flavor intensity when compared with samples aged for 21 d. Within 80 d of aging, wet-aged loins had higher off-flavor intensity than dry-aged. Steaks from loins aged 21 d were more desirable than steaks from loins aged for 80 d. Panelists scored higher frequencies of liver off-flavor in wet-aged samples and higher frequencies of sour and bitter off-flavors in loins aged for 80 d. Aging beef for 80 d led to higher concentrations of octanal, nonanal, decanal, and 2-5/6-dimethyl pyrazine and lower concentrations of pentanal and acetoin. Dry aging led to higher concentrations of hexanal, heptanal, octanal, 3-methylbutanal, and 2-pentylfuran, whereas wet aging increased concentrations of trimethyl pyrazine. When looking at steak zones, dorsal portions (C) of steaks dry aged for 21 d showed higher concentrations of hexanal, heptanal, octanal, and 2-pentylfuran. Ventral portions of steaks wet aged for 21 d showed higher acetoin concentrations. Regarding effects of volatiles on off-flavor intensity and overall desirability, dimethyl disulfide was positively correlated to off-flavor intensity and negatively correlated to overall desirability in steaks either wet aged or aged for 80 d. Pentanal was also negatively correlated to overall desirability in steaks aged for 80 d. In dry-aged steaks, 3-methylbutanal and 2-butanone were positively correlated with overall desirability. Positive correlations between overall desirability and decanal and trimethylpirazine were also observed in steaks aged for 21 d.

Conclusion: Aging Select short loins either for 21 and 80 d or using wet or dry methods do not affect juiciness and tenderness. Long aging periods may lead to higher off-flavor intensity, especially livery in wet-aged beef and sour and bitter in dry-aged beef. Three methylbutanal and 2-butanone are desirable volatiles from a desirability standpoint, whereas the first one is more abundant in dry-aged beef. Dry aging for periods of about 21 d may improve sensory perception of USDA Select beef.

Keywords: beef, dry aging, meat quality

92 INFLUENCE OF SIRE BREED OF BEEF × HOLSTEIN CATTLE ON CARCASS TRAITS, MUSCLE FIBER PROPERTIES, AND EATING QUALITY

J. L. Frink¹, H. M. Frobose^1*, B. A. Foraker¹, L. K. Fuerniss¹, S. T. Howard², J. F. Legako¹, B. J. Johnson¹, M. F. Miller¹, and D. R. Woerner¹, ¹Meat Science, Texas Tech University, Lubbock, Texas, USA; ²Protein, Cargill, Wichita, Kansas, USA, *hafrobos@ttu.edu

Objectives: Angus and Continental-influenced breeds are the most prevalent sire breeds utilized in the US beef × dairy crossbreeding model; thus, in this study, beef quality differences among crossbred cattle types were evaluated and compared with fed Holstein cattle.

Materials and Methods: Carcasses of crossbred beef × dairy cattle (breed verified by genotype) from either Angus (n = 88), Continental breed influenced (n = 85), or Holstein (n = 118) sires and Holstein dams were selected to equally represent USDA Prime, Upper 2/3 Choice, commodity Choice, and Select grades. Anterior sections of strip loins were collected from both sides of each carcass. A subset of samples (N = 67) from the longissimus lumborum were collected and frozen for myosin heavy chain (MHC) isoform determination. Strip loin sections were fabricated into steaks (2.54 cm thick) and were designated to analyses: shear force, trained sensory, consumer sensory, and retail display. Only steaks from USDA commodity Choice carcasses were displayed at retail for 96 h. Steaks were imaged for steak dimensionality, and pH was measured. Data were analyzed as a completely randomized design in a 3 × 4 factorial arrangement of breed type and quality grade. Breed type, USDA quality grade, and their interaction were included as fixed effects.

Results: Carcasses from cattle sired by continental influenced breeds were intermediate in 12th rib fat thickness (P < 0.01) to carcasses from cattle sired by Angus and Holstein. Continental sired beef × dairy crossbreds possessed the largest ribeye area and had the lowest numerical yield grade (P < 0.01). Straightbred Holsteins had the greatest proportion of MHC-I fibers (P < 0.01). Continental-influenced ×dairy had the greatest proportion of MHC-IIA fibers (P < 0.01) and the greatest cross-sectional area of MHC-IIA, MHC-IIX (P < 0.01). Trained color panel attributes indicated that strip loin steaks from carcasses of Angus sired beef × dairy crossbreds were the brightest cherry-red throughout retail display (P < 0.01). Shear force values–trained sensory analysis and consumer sensory analysis panelists reported that strip loin steaks from Holstein carcasses were the most tender (P < 0.01). No meaningful flavor differences were observed among sire breed type of beef × dairy crossbreds.

Conclusion: Thus, Continental sires can be used to improve carcass merit and red meat yield, whereas Angus sires can be used to generate more favorable retail acceptability by improving color sustainability and when mating to Holstein dams.

Keywords: beef, color, dairy, fiber type, sensory

93 EFFECTS OF GRAIN- AND GRASS-FED DIETS ON CARCASS CHARACTERISTICS AND MEAT QUALITY ATTRIBUTES OF BEEF STEERS

F. Giotto^1*, M. Fonseca¹, and A. S. De Mello¹, ¹Agriculture, Veterinary, and Rangeland Sciences, University of Nevada, Reno, Nevada, USA, *ademello@unr.edu

Objectives: Recently, the demand for grass-fed beef boosted its market growth, which is expected to grow globally by USD 14.50 billion during 2020–2024. In addition, the demand for local beef has also been increasing as consumers raise concerns about where food has been sourced from. Thus, local farmers located on the east and west coasts have been finishing beef with grass diets to explore niche markets. In this study, we evaluated the effects of grain and alfalfa-only diets on marbling score, yield grade, and meat quality attributes of steers.

Materials and Methods: Twenty-four steers weighing approximately 384 ± 12.14 kg were randomly assigned to one of 2 dietary treatments (grain-fed n = 12 and grass-fed n = 12 animals per treatment). Diets were formulated with 80% corn and 20% alfalfa hay (16% CP–grain fed); and 100% alfalfa hay (21% CP–grass fed). All animals were fed individually and offered ad libitum amounts of water. After 120 d, animals were transported to and slaughtered at a commercial beef processing plant. Approximately 24 h postmortem, the yield grade, ribeye area, and marbling score were obtained directly from the plant’s electronic instrument grade augmentation system. The short loin was removed from the carcasses and transported under refrigeration to Wolf Pack Meats, the University of Nevada USDA processing plant. After 7 d, strip loin steaks (1 in.) were fabricated and displayed for 7 d for color and lipid oxidation analysis. One steak was used for proximate analysis, and 2 steaks were used to estimate lipid oxidation. One steak was vacuum packaged at day 7, and the steak used for color analysis (CIE L*, a*, and b*) was vacuum packaged after the end of the display and used for lipid oxidation analysis at day 14. Steaks used for proximate analysis (AOAC, 2005) were vacuum packaged at day 7. Steaks used for Warner-Bratzler shear force were frozen at day 7 d (7-d aging) and day 14 (14-d aging). Data were analyzed as a completely randomized design in which color and lipid oxidation data were evaluated as a repeated measure. Data were analyzed using the CORR and GLIMMIX procedures of SAS (SAS Institute Inc., Cary, NC). Means were considered different at P ≤ 0.05.

Results: Dietary treatments did not affect fat, ribeye area, yield grade, lipid oxidation, Warner-Bratzler shear force, or b*. Moisture (P < 0.0001) and marbling (P = 0.0009) values were higher in steaks from steers fed grain than for those fed grass. A moderate positive correlation was observed for fat and marbling (r = 0.64, P = 0.0008). Samples from animals fed grain were lighter (P = 0.0461) and redder (P < 0.0001) than samples from animals fed grass. Samples aged 14 d had higher values for MDA/kg than samples aged 7 d (P < 0.0001). As expected, steaks aged 14 d were more tender than steaks aged 7 d (P < 0.0001). For L*, no effect of display was observed on samples. For a*, samples were redder on days 3 and 4 when compared with samples on day 7 of display. For b*, a slight increase was observed from samples displayed for 7 d when compared with day zero.

Conclusion: Animals fed grain had greater marbling deposition than animals fed alfalfa diets. Overall, beef finished with alfalfa hay for 120 d with levels of crude protein about 21% may provide similar yield grade, lipid oxidation, and slight color differences when compared with grain-fed beef.

Keywords: beef, grass-fed, meat quality

94 NUTRIENT PROFILE OF USDA PRIME BEEF CUTS

E. G. Mortensen^1*, T. M. Horton¹, B. A. Foraker¹, J. F. Legako¹, L. D. Thompson¹, J. C. Brooks¹, M. F. Miller¹, and D. R. Woerner¹, ¹Department of Animal and Food Sciences, Texas Tech University, Lubbock, Texas, USA, *emma.mortensen@ttu.edu

Objectives: USDA Prime beef has increased from 3.3% of graded beef carcasses in 2000 to 10.3% in 2020. Accurate nutrient information is needed for USDA Prime beef cuts as they are becoming more available in retail and foodservices settings. Additionally, USDA beef cuts are not well represented by current data in the USDA National Nutrient Database for Standard Reference. The objective of this study was to provide a full and accurate nutrient profile for frequently purchased USDA Prime beef cuts.

Materials and Methods: Strip loin steaks, tenderloin steaks, ribeye steaks, top sirloin steaks, and rib roasts (Institutional Meat Purchase Specifications #1180, #1189, #1112, #1184, and #108, respectively) from USDA Prime beef carcasses were collected from 6 geographical locations during 3 seasonally spaced collections. Raw and cooked evaluations were done on retail cuts (N = 180; 5 cuts × 6 locations × 3 collections × raw or cooked). For cooked evaluation, steaks were pan grilled and rib roasts were oven roasted. All cuts were dissected into separable lean, internal fat, external fat, and refuse components. For laboratory analyses, separable lean of each cut type, from each evaluation (raw or cooked), and from each location were homogenized and composited per collection (n = 3 per cut and cook type). Raw ribeye steaks and rib roasts were composited together, while cooked ribeye steaks and rib roasts were composited separately due to different cooking methods. Internal and external fat of all cut types from each evaluation (raw or cooked) and each collection were composited together. Proximate composition (crude protein, lipid, moisture, and ash), fatty acid profile, amino acid profile, mineral content, cholesterol content, and fat soluble plus B-vitamin content was determined for each composite (N = 33).

Results: Compared with USDA Choice beef cuts in the USDA National Nutrient Database for Standard Reference, each of the 5 USDA Prime beef cuts evaluated in this study had a greater percentage of total lipid. As a result, water-soluble vitamins and minerals were decreased in Prime beef. Nonetheless, all Prime cuts still qualified as an excellent source of total protein, zinc, niacin, and Vitamin B12 on a raw, separable lean basis (containing greater than 20% of daily values as established in the Dietary Reference Intakes). Additionally, tenderloin steaks, ribeye steaks, and top sirloin steaks classified as a good source of iron (containing 10% to 19% of daily values as established in the Dietary Reference Intakes). Prime tenderloin and top sirloin steaks contained less than 10 g of total fat on a raw and separable lean basis, qualifying them as lean beef cuts. Fatty acid analysis determined 18:1 (oleic Acid), 16:0 (palmitic acid), 18:0 (stearic acid), and 18: 2 n-6 (linoleic acid) in the greatest concentrations; respectively. Of the fatty acid fraction, “heart healthy” monounsaturated fatty acids composed 51%, 47%, 49%, and 48%, respectively, in the raw, separable lean portions of strip loin steak, tenderloin steaks, top sirloin steaks, and rib roasts.

Conclusion: USDA Prime beef is a good and excellent source for protein, as well as various essential nutrients. Although the total lipid content is greater in Prime versus Choice beef, the fatty acid composition offers a good amount of beneficial monounsaturated fatty acids. Nutrient data from this study may be used to update the USDA Nutrient Database, which is pertinent for educating consumers, health professionals, dietitians, and legislators.

Keywords: beef, prime, nutrition, protein, fatty acids

95 VALIDATING THE ABILITY OF RAPID EVAPORATIVE IONIZATION MASS SPECTROMETRY (REIMS) TO DIFFERENTIATE LAMB FLAVOR PERFORMANCE BASED ON CONSUMER PREFERENCE

E. Bechtold^1*, B. Kelly ², J. C. Brooks³, J. F. Legako³, M. F. Miller³, and D. R. Woerner³, ¹Department of Animal and Food Sciences, ²Department of Soil and Crop Sciences, and ³Department of Animal and Food Sciences, Texas Tech University, Lubbock, Texas, USA, *emmy_bechtold@yahoo.com

Objectives: The objective of this study was to investigate the capability of rapid evaporative ionization mass spectrometry (REIMS) to accurately identify and predict cooked sheep meat flavor and carcass characteristics based on consumer response utilizing metabolomics data acquired from raw samples.

Materials and Methods: Boneless leg samples (n = 200) were collected from sheep representing 2 age classifications (n = 99 lamb, n = 101 yearling), at 3 USDA harvest facilities located in California and Colorado. Collections were completed between the months of September 2019 and January 2020. Consumer sensory panels (2019-590) consisted of 200 panelists who answered a series of questions regarding flavors and overall liking of ground sheep patties. REIMS platform captured metabolomics data from lean tissue, external fat tissue, and ground patties. New binary values were developed, and levels of intensity based on consumer responses developed predictive models. Principal component analysis (PCA) reduced data dimensionality prior to creating the model using linear discriminant analysis (LDA). Additionally, Top 100 REIMS bins were determined by an f-statistic value before the model using LDA was created. Moreover, Top 100 REIMS bins were entered into University of California San Diego Metabolomics Workbench to determine possible compounds responsible for sheep characteristics and flavor attributes (Metabolomics Workbench, University of California San Diego, San Diego, CA).

Results: Results show that Top 100 REIMS bins were more effective overall when classifying attributes and predicting overall accuracy. Overall accuracies were above 80% for all sheep flavor attributes and characteristics with production background (grain-fed or grass-fed) revealing up to 100% classification accuracies. In comparison, the PCA-LDA model revealed lower overall accuracies for all attributes. However, the PCA-LDA model classified production background (grain-fed or grass-fed) at high overall accuracies with lean tissue at 97.50%, external fat tissue at 95.00%, and ground sensory patty at 97.50%.

Conclusion: Promising results were discovered from the metabolomics database, possible compounds from previously published literature correlated to sheep flavor attributes and characteristics.

Keywords: lamb flavor, lamb quality, metabolomics, rapid evaporative ionization mass spectrometry

96 WHOLE GENOME SEQUENCING STUDY OF SHORT-TERM EVOLUTION OF SHIGA TOXIN–PRODUCING ESCHERICHIA COLI O157:H7 IN CATTLE

M. D. Weinroth^1*, A. Kalalah², M. Eppinger², L. Liou³, H. Sheng³, L. Austin³, C. J. Hovde³, M. L. Clawson⁴, and J. L. Bono⁵, ¹USDA, Agricultural Research Service. U.S. National Poultry Research Center, Poultry Microbiological Safety and Processing Research Unit, Athens, Georgia, USA; ²Department of Biology, The University of Texas at San Antonio, San Antonio, Texas, USA; ³Department of Microbiology, Molecular Biology, and Biochemistry, University of Idaho, Moscow, Idaho, USA; ⁴USDA, Agricultural Research Service, U.S. Meat Animal Research Center, Genetics, Breeding and Animal Health Research Unit, Clay Center, Nebraska, USA.; ⁵USDA, Agricultural Research Service, U.S. Meat Animal Research Center, Meat Safety and Quality Research Unit, Clay Center, Nebraska, USA, *maggie.weinroth@usda.gov

Objectives: Shiga toxin–producing Escherichia coli (STEC) O157:H7 is a foodborne pathogen that cattle are known to harbor. The objective of this study was to understand how the genomes from 4 different STEC O157:H7 strains inoculated into cattle at the rectal anal junction changed over 31 d.

Materials and Methods: At the start of the study, 16 cattle were randomly divided into 4 groups and sampled for STEC O157:H7 and then subsequently inoculated at the rectal anal junction with one of 4 STEC O157:H7 parent strains: 2 tir 255 T>A T allele strains (NE1127 and NE1092) and 2 tir 255 T>A A allele strains (TX376 and NE1040). Strains with different tir alleles were chosen owing to this polymorphism’s association with the propensity to cause human clinical disease. After inoculation, STEC O157:H7 strains were recovered on 10 different days over the course of 31 d through traditional culture enrichment and plating techniques. STEC O157:H7 was recovered from all animals, with the highest numbers found on days 1 to 10, and through enrichment on days 14 to 31. Short-read sequencing was conducted on 592 strains from 14 animals that passed quality control.

Results: Recovered strains from all animals were compared with their parental inoculant strain. Most exhibited little to no change from their parental strain, with 38.7% containing no single nucleotide polymorphisms (SNP) in the core genome and an additional 19.3% and 17.7% containing 1 or 2 SNP, respectively, for a total of 75.7% of all strains having 2 or fewer SNP. Among all strains recovered, there were 322 specific gene locations where SNP were identified. Of these SNP, 232 (72%) only occurred in one strain at one location. Finally, there were 24 SNP that occurred within multiple animals inoculated with the same parental strain, representing 10 genes (2 with multiple SNP within the same gene) and 4 intergenic regions (one with 4 SNP over an 11-base-pair length).

Figure:

(A) average number of single nucleotide polymorphism (SNP) differences of a recovered strain versus its inoculant parent across all animals (B) count of the total number of SNP differences from the inoculant parent stain by day across all recovered strains.

Conclusion: Observing variation among different strains of STEC O157:H7 in a bovine colonization model contributed to understanding short-term genetic changes of this pathogen in its natural host.

Keywords: E. coli, Escherichia coli O157:H7, Shiga toxin–producing Escherichia coli, whole genome sequencing

97 ANTIMICROBIAL EFFICACY OF CHEMICAL TREATMENTS AGAINST TWO INOCULATION LEVELS OF SALMONELLA ENTERICA ON PORK JOWLS

S. Gonzalez Sanchez^1*, I. Geornaras¹, J. O. Reagan², S. Mixon², M. N. Nair¹, and K. E. Belk¹, ¹Animal Sciences, Colorado State University, Fort Collins, Colorado, USA; ²Technical Services, Zoetis Inc., Parsippany, New Jersey, USA, *sara.gonzalez@colostate.edu

Objectives: Salmonella is responsible for more than 1.3 million infections in the US every year and is the leading cause of foodborne-illness–related hospitalizations (26,500/y) and deaths (420/y). Livestock, such as swine, are usually asymptomatic carriers of Salmonella, which can lead to a high prevalence of this pathogen at the farm that can be carried to the abattoir. A 13.6% Salmonella prevalence has been reported on raw pork products collected from federally inspected slaughter and processing establishments in the US. Nevertheless, research on novel antimicrobial interventions for decontamination of pork carcasses and products is limited. Therefore, the objective of this study was to evaluate the decontamination efficacy of various chemical treatments when applied to pork jowls inoculated with a high or low contamination level of Salmonella enterica.

Materials and Methods: Chilled pork jowls were cut into 10 × 5 × 1 cm portions and were surface inoculated on the skin side with a mixture of 6 S. enterica serotype strains. Inoculation levels targeted were 6 to 7 log CFU/cm² (high) and 3 to 4 log CFU/cm² (low). Inoculated samples were left untreated (control) or were treated by spray application (10 s, 18 to 19 psi, 1.0 gpm flow rate) with water, a sulfuric acid and sodium sulfate blend (SSS, pH 1.2), formic acid (1.5%), peroxyacetic acid (PAA, 400 ppm), or PAA (400 ppm) that was pH adjusted (acidified) with acetic acid (1.5%), formic acid (1.5%), or SSS (pH 1.2). Samples were analyzed for Salmonella populations immediately after treatment application (0 h) and after 24 h of refrigerated (4°C) storage. The study was designed as an 8 (treatments) × 2 (sampling times) factorials for each inoculation level (high, low), blocked by trial day. The experiment was repeated on 2 separate days for each inoculation level, and 3 samples were analyzed per treatment and sampling time in each trial (n = 6 samples per treatment and sampling time). Data were analyzed using the emmeans package in R (version 3.5.1). Least-squares means were separated using a significance level of α = 0.05.

Results: Overall, initial pathogen levels on jowls inoculated at the high (6.2 log CFU/cm²) and low (3.5 log CFU/cm²) contamination level were reduced (P < 0.05) by 1.2 to 1.9 log CFU/cm² and 1.0 to 1.7 log CFU/cm², respectively, following spray application of the tested chemical treatments. For the high inoculation level, Salmonella counts of samples analyzed after 24 h of refrigerated storage were, in general, similar (P ≥ 0.05) to the counts of the corresponding treatment at 0 h. However, for samples inoculated at the low inoculation level, pathogen counts recovered from jowls treated with SSS, formic acid, or PAA acidified with formic acid and held at 4°C for 24 h were 0.6 log CFU/cm² lower (P < 0.05) than the 0-h counts of the corresponding treatment. Regardless of inoculation level or sampling time, no (P ≥ 0.05) differences in efficacy were obtained between PAA and any of the acidified PAA treatments evaluated.

Conclusion: All evaluated chemical spray treatments effectively reduced both the high and low Salmonella contamination levels on pork jowls. Under the conditions of the study, acidification of PAA with 1.5% acetic acid, 1.5% formic acid, or SSS (pH 1.2) did not enhance the bactericidal effects of PAA.

Keywords: antimicrobials, peroxyacetic acid, pork, Salmonella enterica

98 THE EFFECT OF A DIRECT-FED MICROBIAL (10-G) ON SALMONELLA PREVALENCE IN LYMPH NODES AND FECES OF FED BEEF HEIFERS

L. M. Mayer^1*, K. Martens², L. W. Lucherk¹, T. Lawrence¹, and T. C. Tennant¹, ¹Beef Carcass Research Center, West Texas A&M University, Canyon, Texas, USA; ²Life Products Inc., Norfolk, Nebraska, USA, *lmayer@wtamu.edu

Objectives: Salmonella is a naturally occurring bacteria that is known to cause upward of 1.35 million cases of foodborne illnesses annually. Ground beef products may be manufactured from trimmings containing Salmonella-infected lymph nodes, which has led to pending rulemaking by the USDA Food Safety and Inspection Service to declare Salmonella as an adulterant. Direct-fed microbials are a pre-harvest intervention for reduction of Salmonella. The objective of this study was to determine the efficacy of a direct-fed microbial upon the prevalence and enumeration of Salmonella in feces and lymph nodes.

Materials and Methods: Heifers (n = 1,394; 291 ± 9.9 kg) were blocked by day of arrival and randomly allocated to one of 2 treatments (0 g or 2 g/animal/d for CON and 10-G, respectively) with 10 pens per treatment. Heifers fed 10-G were provided 1 billion CFU per animal per day of Lactobacillus acidophilus, Enterococcus faecium, Pediococcus pentosaceus, Lactobacillus brevis, and Lactobacillus plantarum. Twenty-four animals were randomly selected from each pen for Salmonella sampling. Rectoanal mucosal swab samples (RAM) were obtained at initial processing and harvest; subiliac lymph nodes were collected at harvest. In addition, pen surface fecal pats were collected and composited by pen (10 pats per composite, 5 composites per pen) on days 0, 52, 120, and 170. Microbiology data were analyzed using the GLIMMIX procedure of SAS (SAS Institute Inc., Cary, NC) with pen as experimental unit and block as random effect.

Results: Salmonella prevalence of RAM did not differ between treatments at initial processing (P = 0.92; CON = 11.6%, 10-G = 11.5%) or at harvest (P = 0.92; CON = 99.0%, 10-G = 98.6%); however, RAM differed (P < 0.01) in Salmonella prevalence between the 2 collection times. Likewise, Salmonella log (mpn/g) of RAM did not differ between treatments at initial processing (P = 0.63; CON = 0.28, 10-G = 0.30) or at harvest (P = 0.63; CON = 4.40, 10-G = 4.05), whereas log (mpn/g) of Salmonella increased (P < 0.01) over the feeding period. Moreover, composited pen level fecal pats were similar for Salmonella prevalence (P = 0.73; CON = 69.0%, 10-G = 67.0%) between treatments, but prevalence increased (P < 0.01) sharply during the initial 52 d and then plateaued during the remainder of the finishing period. However, Salmonella prevalence differed (P < 0.01) among sampling days. Cattle fed 10-G had a lower frequency of Salmonella-positive lymph nodes (P = 0.01; CON = 15.80%, 10-G = 7.41%) than CON. However, Salmonella log (mpn/g) of lymph nodes did not differ between treatments at harvest (P = 0.34; CON = 0.73, 10-G = 0.34).

Conclusion: These data indicate that cattle fed 10-G had fewer Salmonella-positive lymph nodes, which in turn can likely improve public health by reducing the number of foodborne illnesses caused by Salmonella.

Keywords: direct-fed microbial, heifers, Salmonella

99 A NITRITE-ALTERNATIVE INGREDIENT INHIBITS CLOSTRIDIUM PERFRINGENS IN A MODEL MEAT SYSTEM DURING EXTENDED COOLING

G. McCoy¹, D. Unruh^1*, S. LaSuer¹, S. Baker¹, and T. Rourke¹, ¹Corbion, Corbion, Lenexa, Kansas, USA, *daniel.unruh@corbion.com

Objectives: The USDA Food Safety and Inspection Service released guidance documentation regarding compliance guidelines for cooling heat-treated meat and poultry products, known as Appendix B. Products formulated with inhibitory ingredients may be qualified for extended cooling. Here, a novel cultured cane sugar and vinegar (CCSV) ingredient, designed as a nitrite-replacement product, is validated to inhibit Clostridium perfringens in a meat model system.

Materials and Methods: Three strains of C. perfringens spores were prepared and added to raw meat batter, comprising ground pork semimembranosus and treatment. If necessary, sodium bicarbonate and carrageenan were added to product formulation to achieve target pH (6.3 ± 0.05), moisture (72% ± 0.07%), and salt levels (2.0% ± 0.25%). Treatments comprised a negative control (no treatment), positive control (100 ppm sodium nitrite: 250 ppm sodium erythorbate), and 3 levels of CCSV (1.9%, 2.2%, and 2.5%). Spores were added to meat samples at target level 2.5 log CFU/g and mixed for 3 min. Samples were portioned (50 g) into bags, vacuum packaged, pressed to uniform thickness (3 mm), and stored (4°C) until heat treatment. Upon heating, samples were placed in water baths (75°C) to heat shock the spores (target 73°C product temperature), then were removed from water bath and subjected to biphasic cooling. Two cooling profiles were analyzed: modified cooling phase (54.4°C to 26.7°C in 2.5 h; 26.7°C to 7.2°C in 10 h) and Appendix B Option 3 (54.4°C to 26.7°C in 5 h; 26.7°C to 7.2°C in 10 h). Samples were enumerated, in triplicate, at 0-time (immediate post-cook), 2.5, 5, 7.5, 10, and 15 h. Samples were diluted in 50 mL Bufferfield’s buffer and stomached for 2 min. Samples were diluted and spread plated on tryptose-sulfite-cycloserine agar with a tryptose-sulfite-cycloserine agar overlay (anaerobic incubation, 35°C, 24 h). Two trials were conducted.

Results: Application of CCSV inhibited outgrowth of C. perfringens. The negative control displayed growth rate and pattern similar to predictions made using ComBase. The positive control and all CCSV treatments showed no growth of C. perfringens, with a decrease in counts often recorded. Specifically, in Trial 1 modified cooling profile (total time 12.5 h), the uncured control exceeded 1.0 log CFU/g outgrowth by 7.5 h, whereas the cured control and treatments (1.9%, 2.2%, and 2.5% CCSV) resulted in population changes of −0.6, −1.11, −1.15, and −1.02 log CFU/g, respectively, at 12.5 h. For the Option 3 cooling profile, the uncured control exceeds 1.0 log CFU/g outgrowth at 2.5 h, 2.0 log CFU/g outgrowth at 5 h, and 4.0 log CFU/g outgrowth at 7.5 h. Cured control and treatments resulted in population changes of −1.06, −1.08, −1.09, and −1.30 log CFU/g, respectively, at 15 h. For Trial 2, results for the modified cooling profile showed greater than 1.0 log CFU/g outgrowth in negative control by 7.5 h, whereas the cured control and treatments resulted in changes of −0.90, −0.85, −1.01, and −0.97 log CFU/g, respectively, at 12.5 h. Results for Trial 2 Option 3 cooling are given in the table. In both trials, traditional curing and CCSV resulted in significant (P < 0.05) population changes compared with negative control.

Conclusion: Application of CCSV inhibits the outgrowth of C. perfringens in a model meat system, achieving food safety standards outlined in Appendix B. Use of CCSV can serve as an alternative food safety system in replacement of sodium nitrite.

Keywords: Appendix B, Clostridium perfringens, cooling

100 EFFICACY OF LACTIC ACID INTERVENTIONS AT AND ABOVE REGULATORY ALLOWABLE UPTAKE LEVELS ON THE REDUCTION OF PATHOGENIC BACTERIA

K. R. Loomas^1*, S. E. Blandon¹, D. A. Vargas¹, D. E. Casas¹, A. Echeverry¹, M. F. Miller¹, C. E. Carpio², M. X. Sanchez-Plata¹, and J. F. Legako¹, ¹Animal and Food Science and ²Agricultural and Applied Economics, Texas Tech University, Lubbock, Texas, USA, *kloomas@ttu.edu

Objectives: In fresh ground products, pathogenic bacteria such as Salmonella and Shiga toxin–producing Escherichia coli can be reduced by organic acid interventions. Currently, fresh beef trim processors are allowed a maximum uptake percentage of 0.49% added weight post intervention application. The objective of this study was to evaluate the efficacy of lactic acid (4.5%) intervention uptake of ≤0.49% to ≥0.49%. Uptake percentages were achieved through both spray and dip applications of lactic acid on fresh beef trim.

Materials and Methods: For this study, 7 strains of Shiga toxin–producing E. coli (STEC) (O26, O103, O45, O111, O121, O145, and O157:H7) and 3 strains of Salmonella (Salmonella Typhimurium, Salmonella Newport, and Salmonella Enteritidis) were used to inoculate beef trim samples. Beef trim of 2 different lean levels (90/10 and 50/50) were collected from a commercial meat processing facility. Beef trim size was reduced by cutting to achieve 20-g pieces (±2 g), and 46 pieces were placed in a 22 × 28 cm bag and then distributed on a tray covered in foil. Trim pieces were then inoculated with the E. coli or Salmonella strains using a multi-purpose spray bottle (15 psi) and left for 20 min to allow bacteria to attach. Trim pieces were weighed before and after the application of the intervention to calculate uptake percentage. The spray and dip applications were applied with a 4.5% lactic acid solution to trim pieces in 1-, 5-, and 10-s intervals. After the interventions were applied, trim pieces stayed on the tray for 1 min and then were placed into a bag for 5 min to simulate a combo bin at a commercial processing facility. After the trim was weighed post intervention, the pieces were transferred to a 2-L filtered whirl-pack bag, and 500 mL of buffered peptone water was added; then, the sample was mixed for 30 s to have a homogenous sample. Meat rinsates were serially diluted, plated in triplicate, and incubated for 18-24 h at 37°C. Bacterial counts were log transformed for statistical analysis. A regression analysis was performed to observe the relationship between uptake percentage and the reduction of pathogenic bacteria.

Results: In the regression model used for this study, for every 1% increase in uptake percentage, there was an average reduction of 0.16 LogCFU/g for STEC and Salmonella using lactic acid interventions (P < 0.01). In the 50/50 trim, there was an increase in the reduction of Salmonella by 0.11 LogCFU/g (P = 0.05) and a decrease in the reduction of STEC by 0.03 LogCFU/g (P ≥ 0.46) for every 1% increase in uptake percentage. In the 90/10 trim, there was a decrease in reduction in Salmonella by 0.10 LogCFU/g (P = 0.15) and STEC by 0.26 LogCFU/g (P ≤ 0.004).

Conclusion: This study found that an increase in uptake percentage using a organic acid intervention significantly reduced pathogenic Salmonella and E. coli bacteria in fresh beef trim. Further research should be done at commercial processing facilities to see whether the same results can be found when experiments are performed on a larger scale.

Keywords: antimicrobial, bacteria, pathogen, uptake level

101 EVALUATION OF THE AVIAN, BOVINE, AND PORCINE FECAL MICROBIOME AND THEIR EFFECT ON SUBSEQUENT MICROBIAL ENVIRONMENTS

E. A. Rice^1*, L. J. Pinnell², M. D. Weinroth¹, E. Doster¹, N. R. Noyes³, J. K. Parker¹, C. Anderson¹, K. Crone¹, K. E. Belk¹, M. N. Nair¹, and P. S. Morley², ¹Department of Animal Sciences, Colorado State University, Fort Collins, Colorado, USA; ²Veterinary Education, Research and Outreach Program, Texas A&M University, Canyon, Texas, USA; ³Department of Veterinary Population Medicine, University of Minnesota, St. Paul, Minnesota, USA, *emily.rice@colostate.edu

Objectives: Animal feces are biological contaminants of concern for the meat industry owing to their potential to adulterate meat products during harvest. Fecal waste is also commonly applied as amendments to crops, providing another potential route to enter the food supply chain. Although fecal contamination of meat products has the potential to be a public health hazard, many consumers view the use of animal waste as a fertilizer to be more beneficial than the application of chemicals to crop land. The extent to which fecal microbial communities can impact the microbiomes of meat products and soil needs further investigation. Therefore, the objective of this study was to use 16S ribosomal RNA gene sequencing to characterize how fecal waste from different meat animal operations was associated with the microbiome of meat rinsates and the microbiome of soil where fecal waste was used as an amendment.

Materials and Methods: Composited fecal samples were collected from 3 commercial operations: beef feedlot, finishing swine operation, and broiler chicken operation (n = 20/species). Meat rinsates (n = 20/species) were obtained from the harvest of the animals from the same facilities. After feces or litter (from the same cohorts of animals) was composted and spread, soil samples (n = 20/species) were collected from fields. Additionally, human waste samples were collected from wastewater treatment plants in close proximity to each production operation (n = 14/species). DNA was extracted from samples using the PowerMax Soil DNA Isolation Kit according to the manufacturer’s protocol. The V4 region of the 16S ribosomal RNA subunit was polymerase chain reaction amplified with the 515F/806R primer pair, and sequencing (2 × 250 bp) was conducted on a HiSeq 2500. Microbiome data were analyzed using QIIME2. Reads were denoised using DADA2, taxonomy was assigned using pretrained Naïve Bayes classifier Diversity metrics, and differences were calculated using R and QIIME2. SourceTracker2 was used to determine the extent to which the fecal microbiome influenced the associated environmental microbial communities.

Results: Ten million reads were classified taxonomically to 6,868 amplicon sequence variants with an average of 52,841 reads per sample. Shannon’s Diversity Index was different (P < 0.05) within species for both avian and bovine sampling locations, respectively. Additionally, within porcine samples, soil and wastewater samples had similar (P > 0.05) Shannon’s Diversity Indexes that were greater (P < 0.05) than fecal and meat samples. Weighted and unweighted UniFrac values clustered by environment (fecal, meat, soil, or wastewater), indicating that the microbial communities associated with each environment were different (P < 0.05). This was further supported by the SourceTracker2 report, which showed that a low percentage of the environmental samples (meat, soil, wastewater) could be sourced back to feces, regardless of species.

Conclusion: The differences in microbial community structure between fecal samples and their subsequent environments in all species, and the low percentage of environmental communities attributed to fecal origins, suggest that animal waste has minimal influence on the microbial communities of associated environments. Ultimately, this could provide additional evidence that there is minimal concern of pathogen introduction or increased antimicrobial resistance from fecal applications.

Keywords: beef, chicken, fecal microbiome, human, pork

102 EFFECTIVENESS OF ORGANIC ACIDS ON THE FATE OF ESCHERICHIA COLI ATCC BAA-1427 IN FRESH GROUND PORK PATTIES

G. Franke^1*, B. L. Preuss¹, J. L. Speshock², W. B. Smith¹, A. M. Cassens¹, and L. A. Kinman¹, ¹Animal Science and ²Biological Sciences, Tarleton State University, Stephenville, Texas, USA, *grace.franke@go.tarleton.edu

Objectives: Fresh pork products are susceptible to pathogen contamination during processing. Organic acids have been evaluated as effective antimicrobials that can be used in the meat industry. The objective of this study was to determine the effectiveness of malic and tartaric acid as antimicrobials in ground pork patties compared with acetic acid.

Materials and Methods: Surrogate nonpathogenic Escherichia coli ATCC BAA-1427 was hydrated by adding 1 mL of trypticase soy broth into a vial containing a lyophilized culture and transferring it into a 15-mL conical falcon tube, then incubated for 24 h at 37°C. An aliquot of the surrogate microorganism was taken from the incubated culture and plated on an agar plate by quadrant streaking and incubated for 24 h at 37°C to ensure culture purity. A single, isolated colony was used to inoculate 5 mL of trypticase soy broth to generate another overnight culture for use in the study. An initial batch of ground pork (7,000 g) was inoculated with 3,500 uL of E. coli ATCC BAA-1427. Pork rested for 1 h at 4°C to allow for attachment and then mixed by hand for 5 min to allow for dispersion. Inoculated pork was separated into seven 907-g batches, and treatments were applied. There were 7 treatments: a negative control, a positive control (acetic acid), and malic and tartaric acids at either 1.5% or 3% concentration rate. Each batch was then re-mixed for 3 min to allow dispersion of organic acids. Two replications of 6 patties (149 g) per treatment were placed on Styrofoam trays and overwrapped with polyvinyl chloride film, arranged into a retail display case maintained at 2°C for 12 d. Pork patties were subjected to microbial collection on days 1, 2, 4, 6, 8, 10, and 12. Five-gram microbial samples were placed into a sterile stomacher bag filled with 195 mL of DI water and homogenized for 30 s. Serial 5-fold dilutions were done and plated on eosin methylene blue agar plates, spread evenly across the surface using a sterile inoculating loop, and incubated for 24 h at 37°C. Colonies were enumerated and reported as colony forming units (CFU). Statistical analysis was performed using the F-Protected t test in SAS version 9.4 (SAS Institute Inc., Cary, NC). The analysis of variance was analyzed using time as the repeated measure, sample number as the subject, treatment as the fixed effect, and rep as the random effect. Separation of means was performed by using the least significant differences in Saxton’s PDMIX800 macro. Differences were reported at α = 0.05.

Results: There were no differences (P > 0.05) noted among treatments for the presence of E. coli in patties. However, differences were found in E. coli populations over retail display. On day 6, E. coli populations were significantly the highest (354 CFU/1 mL/5 g). Additionally, E. coli populations declined (P < 0.05), following day 6 to similar values (P > 0.05) as day 1 and 2 of retail display.

Conclusion: Malic and tartaric acids resulted in similar E. coli populations compared with acetic acid over retail display. There is potential for tartaric and malic acids to be used as effective antimicrobials, which could inhibit bacterial resistance.

Keywords: ATCC BAA-127, Escherichia coli, ground pork, organic acids

103 PREVALENCE AND ANTIMICROBIAL SUSCEPTIBILITY OF E. COLI IN MARKET SWINE AND CATTLE COLLECTED FROM STOCK SHOWS PRE AND POST IMPLEMENTATION OF THE VETERINARY FEED DIRECTIVE

K. Hardegree^1*, K. Werland¹, J. Kellermeier¹, and L. Branham¹, ¹Department of Agriculture, Angelo State University, San Angelo, Texas, USA, *loree.branham@angelo.edu

Objectives: The objective of this study was to estimate the prevalence and characterize the antimicrobial susceptibility profiles of Escherichia coli isolates obtained from 2020 show animals, after the Veterinary Feed Directive (VFD) implementation, and compare them with similar isolates collected in 2015, before VFD implementation.

Materials and Methods: Fecal samples collected from swine (n = 40) and cattle (n = 40) were enumerated for E. coli using 3M E. coli/Coliform Count Plates, and 4 isolates/sample were isolated onto MacConkey Agar for further testing. Antimicrobial testing was conducted with a microbroth dilution method using Trek Diagnostic Sensititre plates. Isolates were tested against 14 antimicrobial agents important to human and animal health, including cefoxitin, azithromycin, chloramphenicol, tetracycline, ceftriaxone, amoxicillin/clavulanic acid, ciprofloxacin, gentamicin, nalidixic acid, ceftiofur, sulfisoxazole, trimethoprim/sulfamethoxazole, ampicillin, and streptomycin. Resistance breakpoints used were established by Clinical Laboratory Standards Institute. Data were analyzed using procedures of SAS (version 9.3, SAS Institute Inc., Cary, NC). Overall percentage isolates resistant to antimicrobials was determined, as well as differences in minimum inhibitory concentrations (MIC) between pre- and post-VFD samples.

Results: Of the 309 total post-VFD isolates, 71.84% were resistant to at least one antimicrobial, whereas 80.30% of pre-VFD isolates (n = 662) were resistant to at least one antimicrobial. Of the 159 post-VFD swine isolates, 80.50% were resistant to tetracycline and 43.40% to streptomycin; comparatively, of the 330 pre-VFD swine isolates, 96.67% exhibited resistance to tetracycline followed by 69.70% to sulfisoxazole. Of the 159 post-VFD cattle isolates, 48.00% exhibited resistance to tetracycline and 26.67% to streptomycin; comparatively, of the 332 pre-VFD cattle isolates, 55.12% exhibited resistance to tetracycline and 32.53% to streptomycin. A significant interactive effect between the main effects of sampling year and animal species impacted differences in MIC levels in 7 of the 14 antimicrobials tested (P ≤ 0.05). When evaluating differences between pre- and post-VFD swine isolates, a higher MIC level was observed in azithromycin, tetracycline, sulfisoxazole, ampicillin, and streptomycin from pre-VFD samples (P ≤ 0.05); cefoxitin, ceftriaxone, ciprofloxacin, and ceftiofur had a higher MIC level in post-VFD isolates (P ≤ 0.05), and no difference was evaluated between pre- and post-isolates among the remaining 5 antimicrobials (P > 0.05). When evaluating pre- and post-VFD cattle isolates, pre-VFD isolates exhibited a higher MIC level in cefoxitin, azithromycin, tetracycline, ceftiofur, and streptomycin (P ≤ 0.05), whereas no difference was noted in the remaining 9 antimicrobials (P > 0.05). Overall, this study saw varying degrees of susceptibility across the antimicrobials tested.

Conclusion: No consistent pattern of change was seen in MIC levels from pre to post samples for the various antimicrobials studied. Given current regulations, the animal production industry should continue to investigate alternative options to previously used in-feed antimicrobials, including livestock-exclusive antimicrobials, alternative drugs, or non-antimicrobial methods of increasing feed efficiency for livestock.

Keywords: antimicrobial susceptibility, Escherichia coli, show cattle, show swine, Veterinary Feed Directive

104 LACTIC ACID AND SPOILAGE BACTERIA BIOFILMS INFLUENCE STEC PERSISTENCE ON FOOD CONTACT SURFACES AND TRANSFER TO BEEF

Y. Nan^1* on behalf of Dr. Claudia Narváez-Bravo, C. Narváez-Bravo¹, A. Rodas-Gonzalez¹, K. Stanford², X. Yang³, T. McAllister⁴, and C. Nadon⁵, ¹Food and Human Nutritional Science, University of Manitoba, Winnipeg, Canada; ²Biological Science, University of Lethbridge, Lethbridge, Alberta, Canada; ³Lacombe Research and Development Centre, Agriculture and Agri-Food Canada, Lacombe, Alberta, Canada; ⁴Agriculture and Agri-Food Canada, Lethbridge Research Centre, Lethbridge, Alberta, Canada; ⁵Outbreak Detection and Response National Microbiology Laboratory, Public Health Agency of Canada, Winnipeg, Canada, *nany@myumanitoba.ca

Objectives: The impact of biofilm formation on Shiga toxin–producing Escherichia coli (STEC) persistence is often investigated using single-species wet biofilms. However, this may not be representative of beef processing facilities, where spoilage (SP) or lactic acid bacteria (LAB) may form biofilms. This research aimed to evaluate potential synergistic and antagonism interactions of STEC within either LAB or SP wet and dry multispecies biofilms. It was hypothesized that pre-colonization of LAB and/or SP bacteria could reduce STEC adhesion and colonization of food contact surfaces and impede STEC biofilm formation.

Materials and Methods: LAB and SP strains tested were selected based on their biofilm-forming ability. The STEC O103 serogroup was included in this research because of its high prevalence in western Canadian slaughter cattle. One LAB combination, T1: Carnobacterium piscicola + Lactobacillus bulgaricus, and 2 SP combinations, T2: Raoultella sp. + Comamonas sp. and T3: Pseudomonas aeruginosa + Comamonas sp., were selected to form multispecies biofilm at 10°C and 25°C for 6 d on thermoplastic polyurethane (TPU) and stainless steel (SS) coupons. On day 6, STEC O103:H2 was added to the preformed biofilms and incubated for another 6 d. The O103 single-species biofilm was developed as control positive (T4). Coupons covered by mature biofilms (n = 288) were washed with Butterfield Phosphate Buffer and placed in a sterile Petri dish, then randomly assigned to different factors as described in Table 1. A group of SS and TPU coupons were designated to test STEC transfer to beef. The second set of coupons was used for STEC enumeration.

Results: At 25°C, T3 biofilm was the most antagonistic against O103, achieving a 6 log₁₀ CFU/g reduction (P < 0.0001). In addition, O103 remained associated with either single-species (T4) or multispecies biofilms (T1-2) after 60-d storage in moist conditions, causing up to 1.67 Log₁₀ CFU/g meat contamination. Among the different strain combinations, the transfer of O103 to beef samples was reduced (P < 0.05) with aged biofilms, regardless of the moisture or surface type. Approximately 50% of the dry T2 biofilms harbored O103 after 60 d. At 10°C, none (P > 0.05) of the biofilms were antagonistic to O103. With moist biofilms, O103 cell numbers on beef decreased (P < 0.001) from 2.5 at 6 d to 0.6 log₁₀ CFU/g after 60 d. Regardless of the surface type, the transfer of O103 to beef from moist biofilms was at least 1.0 Log₁₀ CFU/g, higher (P < 0.0001) than from dry biofilms. With moist biofilms, the O103 transfer to beef from the TPU surface was higher (P < 0.001) than from biofilms on SS-304. After 60 d of storage under dry conditions, biofilm T2 on TPU and SS-304 surface enhanced O103 survival rate from the range of 0% to 33.33% to the range of 33.33% to 100% compared with T4, respectively.

Conclusion: In conclusion, SP and LAB commonly found in the beef industry could play a significant role in STEC persistence, survival, and cross-contamination. Thus, LAB and SP elimination and biofilm formation prevention on food processing environments are essential to prevent/reduce STEC persistence and survival.

Keywords: multispecies biofilm, persistence, Shiga toxin–producing E. coli

105 FATE OF SALMONELLA IN BEEF STEAKS DURING SOUS VIDE COOKING

H. Hunt^1*, S. Watson¹, B. Chaves², and G. Sullivan¹, ¹Animal Science and ²Food Science, University of Nebraska, Lincoln, Nebraska, USA, *heather.hunt@huskers.unl.edu

Objectives: Sous vide is a method of preparing vacuum-packaged food in hot water baths to achieve a precise degree of doneness throughout the food. It is commonly used in residential and food service kitchens; however, the microbiological safety of this cooking method has not been fully assessed. A previous experiment conducted in our laboratory in response to common cooking guidelines below USDA Food Safety and Inspection Service Appendix A–recommended time and temperatures demonstrated that sous vide cooking of steaks inoculated with generic Escherichia coli did not achieve necessary bacterial reductions for safety at 46°C. To further describe the potential safety risks associated with this cooking application, this experiment was conducted with a cocktail of Salmonella serovars. The objective was to evaluate the safety of beef steaks sous vide cooked to 54°C, 51°C, and 46°C using Salmonella as the challenge organism.

Materials and Methods: One-inch slices of beef semitendinosus muscles were vacuum packaged and frozen until use. For each replication, steaks were thawed (48 h, 4°C) and exposed to UV light for 15 min on each side. Steaks were submerged in liquid inoculum (1 liter each of Salmonella Typhimurium, Enteritidis, and Heidelberg overnight culture) and inoculated to at least 7.4 log₁₀ with a 96-well inoculation pin pad inserted 3 times into each steak. Following inoculation, steaks were air-dried (30 min, 23°C), individually vacuum sealed, and cooked in sous vide water baths. Duplicate steak samples were taken from raw, inoculated steaks and at the following time and holding temperatures: 150 min/46°C, 420 min/46°C, 150 min/51°C, 193.5 min/51°C, 258 min/51°C, 322.5 min/51°C, 64.5 min/54°C, 86 min/54°C, and 107.5 min/54°C. The 54°C sampling at 86 min was taken directly from the USDA Appendix A 5 log₁₀ reduction table. The 51°C and 46°C sampling times were extrapolated from Appendix A and common recommended cooking times, respectively. Core samples (25 g) were homogenized with buffered peptone water, serially diluted, and plated onto xylose lysine deoxycholate agar. The Salmonella colonies were counted after incubation (24 h, 35°C) and reported as log₁₀ CFU/g. Reductions were determined by subtracting concentrations at given sampling times from the raw sample concentrations. Data were analyzed using PROC GLM contrasts in SAS version 9.4 (SAS Institute Inc., Cary, NC).

Results: The minimum time measured for a 5 log₁₀ reduction for 54°C cooking was 64.5 min (P < 0.01). The minimum time measured for a 5 log₁₀ reduction for 51°C cooking was 150 min (P < 0.01). Cooking at 51°C was also able to achieve a final reduction of 7.28 log₁₀ (P < 0.01) after 322.5 min of holding. Cooking at 46°C achieved only a 2.01 log₁₀ reduction (P < 0.01) after 420 min of holding.

Conclusion: Reductions of pathogenic Salmonella in this experiment demonstrate the validity of Appendix A time and temperature cooking combinations for meat products. Cooking nonintact products at 46°C is potentially hazardous. More data are still needed with other relevant foodborne pathogens to determine whether sous vide cooking below Appendix A temperatures could lead to pathogen outgrowth.

Keywords: beef steak, low temperature, Salmonella, sous vide

106 EFFICACY OF PERACETIC ACID INTERVENTION AT AND ABOVE REGULATORY ALLOWABLE PICK-UP LEVELS FOR THE REDUCTION OF E. COLI AND SALMONELLA ON BEEF TRIM

S. E. Blandon^1*, D. A. Vargas¹, D. E. Casas¹, A. Echeverry¹, M. F. Miller¹, C. E. Carpio², M. X. Sanchez-Plata¹, and J. F. Legako¹, ¹Animal and Food Science and ²Agricultural and Applied Economics, Texas Tech University, Lubbock, Texas, USA, *sablando@ttu.edu

Objectives: Foodborne pathogens like Escherichia coli and Salmonella are the leading cause of illness and even deaths worldwide. Numerous antimicrobial interventions are being used in processing plants to reduce pathogens. To consider these agents as processing aids, the retained water cannot exceed 0.49% addition to product weight. The objective of this study was to evaluate the food safety efficacy of peracetic acid at and above required uptake levels for processing aids through spray and dip applications.

Materials and Methods: A general linear regression was performed using the lm built in function of R for the analysis and ggplot2 package for the data visualization (version 4.0.4), where log reduction was used as the dependent variable and uptake percentage was used as the independent variable. A second linear regression model was performed having log reduction as the dependent variable. For the independent variables, uptake, method of application, and trim were used, as well as the interaction of uptake and the other explanatory variables. Beef trim was cut into 20-g pieces and placed separately into a 22 × 28 cm bag adding up to 46 pieces per bag. Afterward, trim was placed evenly on a tray covered with aluminum foil and inoculated using a spray bottle with 7 specific isolates of Shiga toxin–producing Escherichia coli (O26, O103, 045, O111, O121, O145, and O157:H7) or three Salmonella strains (Typhimurium, Newport, and Enteritidis), and its weight was recorded prior to intervention (peracetic acid; 400 ppm) through spray using a multipurpose sprayer (15 psi with an acceptable spray pattern) or dip application for 1-, 5-, and 10-s intervals to obtain a broad uptake level from 0.10% up to 4.2%. Afterward, intervened trim was placed into a 22 × 28 cm bag to weigh and measure pick-up level and then transferred to a 2-L filtered whirl-pack bag to which 500 mL of buffered peptone water was added. The trim was mixed to have a homogenous sample. Meat rinsates were serially diluted and plated following the drop dilution method, and an enumerable range of 2–30 colonies was used to report results after log transformation.

Results: The regression model provided in this study showed that an increase of 1% in uptake percentage will increase the overall reduction by 0.16 LogCFU/g. There is a statistical significance in the reduction of E. coli and Salmonella in relation to the uptake percentage (P < 0.01). When spray application is used, there is a decrease in the reduction of E. coli by 0.68 LogCFU/g compared with dip application (P < 0.01). An increase of 1% in uptake will increase the reduction of Salmonella by 0.11 LogCFU/g. Both lean levels are statistically significant (P < 0.05), where 90/10 trim had a lower reduction than 50/50.

Conclusion: This study showed that interventions using organic acids such as peracetic acid at higher uptake levels significantly reduces pathogens like E. coli and Salmonella in beef trim.

Keywords: antimicrobial, pathogen, processing aids, uptake level

107 APPLICATION OF VINEGAR-BASED ANTIMICROBIALS INHIBIT THE GROWTH OF LISTERIA MONOCYTOGENES IN UNCURED TURKEY BREAST

D. Unruh^1*, S. LaSuer¹, T. Rourke¹, S. Baker¹, and G. McCoy¹, ¹Corbion, Lenexa, Kansas, USA, *daniel.unruh@corbion.com

Objectives: The study objective was to utilize application of vinegar-based antimicrobials in an uncured, sliced turkey breast product to inhibit the growth of Listeria monocytogenes while maintaining sensory attributes.

Materials and Methods: Uncured, sliced turkey breast was produced without antimicrobial, with 1.2% Verdad^® Opti Powder N450 (Vin/SS) and with 1.2% Verdad^® Opti Powder N450 + 0.4% Verdad^® N9 (Vin). Turkey was sliced to a weight of 25 g, left uninoculated (for natural flora analysis) or inoculated with a L. monocytogenes cocktail, vacuum sealed, and stored at 4.4°C. At sampling, inoculated product was enumerated for L. monocytogenes, and uninoculated product was evaluated for natural flora interference and proximate analyses. To enumerate, turkey was transferred to a sterile stomacher bag, diluted 1:2 with buffered peptone water, and stomached at 200 rpm for 30 s. Serial dilutions were performed as necessary, and samples were spread plated, in duplicate on Modified Oxford Agar (35°C incubation for 48 h) for Listeria and de Man, Rogosa, and Sharpe agar (30°C incubation for 48 h) for background flora analysis. After 21 d of storage at 3.3°C, turkey samples were evaluated by a trained panel (n = 10) for saltiness, bitterness, sourness, flavor intensity, tenderness, juiciness, and acceptability using a 7-point scale (1 = no presence; 7 = extreme presence; 9 panelists).

Results: Starting L. monocytogenes counts were ca. 2.4 log CFU/g. Negative control samples exceeded 2 log CFU/g outgrowth between sampling dates 7 and 14, whereas both treatments inhibited outgrowth throughout the 120-d study, with final populations of 1.95 and 1.62 log CFU/g in Vin/SS and Vin, respectively. Counts in both treatments were significantly (P < 0.05) lower than negative control by day 7. There was no statistical (P ≥ 0.05) difference among treatments and control regarding sensory attributes. Statistics were performed using the analysis of variance procedure (with Tukey procedure for population differences) in Minitab 18.

Conclusion: Application of Verdad^® antimicrobials (1.2% Verdad^® Opti Powder N450 and 1.2% Verdad^® Opti Powder N450 + 0.4% Verdad^® N9) inhibits the growth of L. monocytogenes in uncured turkey for 120 d while maintaining acceptable sensory characteristics.

Keywords: food safety, Listeria, shelf life, turkey

108 EFFICACY OF REDUCING SALMONELLA PREVALENCE IN LYMPH NODES FROM INTRADERMALLY INFECTED GOATS BY CARCASS VASCULAR RINSING

K. Hwang^1*, S. Al², R. Campbell³, K. Glass⁴, K. Vogel⁵, and J. R. Claus¹, ¹Animal & Dairy Sciences, University of Wisconsin-Madison, Madison, Wisconsin, USA; ²Department of Food Hygiene and Technology, University of Erciyes, Kayseri, Turkey; ³Technical Services, MPSC Inc., Hudson, Wisconsin, USA; ⁴Food Research Institute, University of Wisconsin-Madison, Madison, Wisconsin, USA; ⁵Department of Animal and Food Science, University of Wisconsin-River Falls, River Falls, Wisconsin, USA, *jrclaus@wisc.edu

Objectives: The study objective was to determine the ability of carcass vascular rinsing (Rinse & Chill^® [RC]; MPSC Inc., Hudson, WI) to reduce Salmonella prevalence in lymph nodes from intradermally infected goats.

Materials and Methods: The experiment was conducted (IACUC A006428) over 2 different trial periods with cull dairy goats (N = 20). The goats consisted of various breeds (Alpine, LaMancha, Nubian, Saanen, Cross), ages (1.5 to 5 y), and live weights (71.2 ± 14.1 kg). Goats with similar characteristics were grouped together in sets of 2 before being randomly assigned to 2 treatments (control [CN]; not vascularly rinsed; n = 10) or vascularly rinsed with a standard rinse solution (TRT: RC; 98.5% water; balance: glucose, polyphosphates, maltose; 9°C; n = 10). Prior to slaughter and treatment application, a lancet (ComforTen^® |Multiple Skin Test Device) was utilized intact (10 surgical steel 1.2-mm lancet tips [10LT]) or reduced to 3 lancet tips (3LT) to intradermally administer Salmonella serotype Enteritidis (SE13). The lancet was dipped into inoculum broth (6.8 × 10⁸ CFU/mL) and then applied with light pressure (each leg with the 3LT, 13 applications; both anatomical sides of the caudal thorax near 12/13th thoracic vertebrae and ventral abdomen with the 10LT, 1 application). After a 7-d incubation period, the animals were stunned by penetrating captive bolt, and one TRT was applied to each carcass immediately upon exsanguination. Carcasses were skinned and eviscerated, and the exterior was sprayed with an antimicrobial (5% lactic acid solution) before being hung in a cooler overnight. After chilling and prior to excising the lymph nodes (superficial cervical, medial iliac, subiliac, mammary), a chlorine bleach solution (400 ppm on chlorine) was applied to the carcass (3 min) followed by a cold-water rinse. Following aseptic procedures, the lymph nodes were dissected and trimmed to remove the majority of the non-lymphatic tissue prior to Salmonella enumeration and percentage moisture analysis. Animal served as the experimental unit. A 2 × 4 factorial design (TRT × lymph node) was used to statistically analyze the data, and trial period served as a covariate in the analysis.

Results: TRT main effect on Salmonella counts was not significant (P = 0.19; CN = 3.82, RC = 3.48, log CFU/g). A TRT × lymph node effect for counts was found (P < 0.05; least significant difference, 1.01 CFU/g). Salmonella counts in the medial iliac of RC (1.56 log CFU/g) were lower than in the CN (2.94 log CFU/g, P < 0.05). No differences in counts (P > 0.05) were found among the subiliac (4.39 log CFU/g), superficial cervical (4.29 log CFU/g), and mammary (3.68 log CFU/g). Percentage moisture in the medial iliac of RC (74.4%) was greater (P < 0.05) than in the CN (68.7%). No differences (P > 0.05) were found in the percentage moisture between CN and RC in the other lymph nodes. Perhaps the greater moisture content in the RC medial iliac suggests that more of the rinse solution reached this lymph node and therefore exposed it to more of the phosphates which are known to have antimicrobial activity.

Conclusion: The Salmonella infectivity model was successful by providing sufficient counts in the lymph nodes so that it could be used to assess the inclusion of other antimicrobial ingredients incorporated into the RC solution. RC was able to demonstrate a 1.3 log reduction in Salmonella but only in the medial iliac lymph node.

Keywords: carcass vascular rinsing, goat, lymph node, Salmonella Enteritidis

109 EVALUATION OF THE TEMPO^® SEMIAUTOMATED SYSTEM FOR THE ENUMERATION OF MICROBIAL INDICATORS: AEROBIC PLATE COUNTS, ENTEROBACTERIACEAE, COLIFORMS, E. COLI, AND LACTIC ACID BACTERIA FOR MEAT AND POULTRY BIOMAPPING STUDIES

K. M. Rodriguez^1*, R. L. Jimenez¹, R. F. Soler¹, D. E. Casas¹, D. A. Vargas¹, I. A. Arvelo¹, and M. X. Sanchez-Plata¹, ¹Animal and Food Sciences, Texas Tech University, Lubbock, Texas, USA, *karla-melissa.rodriguez@ttu.edu

Objectives: The study objective was to evaluate the performance of the bioMérieux Tempo^® Semi-Automated System for the quantification of aerobic plate counts (APC), Enterobacteriaceae (EB), coliforms (CC), Escherichia coli (EC), and lactic acid bacteria (LAB) as compared with reference methods when used in biomapping studies in meat and poultry processing settings.

Materials and Methods: Several microorganisms were selected to test 5 microbial indicators with high importance in spoilage and hygiene of meat and poultry products using the Tempo^® Semi-Automated system: Listeria innocua Seeliger ATCC 33091 for APC, Salmonella enterica subsp. enterica ATCC 14028 for EB, Citrobacter rodentium ATCC 51459 for CC, Escherichia coli ATCC 25922 for EC, and Lactobacillus salivarius L28 for LAB. Each of the microorganisms were aseptically transferred into a tube with 9 mL of tryptic soy broth and incubated at 37°C for 24 h, except for the L28 that was incubated for 48 h. Microorganisms were streaked on tryptic soy agar plates with no selective agents and placed into an incubator for at 37°C for 24 h, except for the L28 that was incubated for 48 h under anaerobic conditions. Typical colonies were transferred with a cotton applicator into 3 tubes with 5 mL of sterile water, and the concentration (1 ∼ 2 × 10⁸ CFU/mL) was verified using a nephelometer (0.5 McFarland turbidity). After reaching concentration, a cocktail combining the 4 standard microorganisms selected for APC, EB, CC, and EC were obtained by placing them together into a 50 mL Falcon conical tube, and for LAB, pure culture was used. Each culture was serially diluted using 9 mL buffered peptone water tubes. Each dilution was treated as an independent sample for testing counts using the 3M^® Petrifilms and the Tempo^® System for APC, EB, CC, and EC and MRS plates for LAB. For LAB, aerobic and anaerobic conditions were evaluated. Counts were log₁₀ transformed and statistically analyzed using R (version 4.04).

Results: The slope of the linear models representing the rate of change in bacterial counts in one method due to an increment of 1 unit in the other method indicate minimal discrepancies in between methodologies. For the APC, EB, CC, and EC, the estimated slopes were 0.96, 0.98, 1.02, and 0.98, respectively. For the LAB evaluation, the estimated slopes were 1.063 and 0.970 for aerobic and anaerobic atmosphere incubation, respectively. All these values are not statistically different from 1, showing significant correlation in between methodologies.

Conclusion: The observed discrepancies in between methods are not significant in microbiological terms to indicate deviations from indicator levels in the samples evaluated. In general, for APC, the Tempo^® system counts 0.5 Log₁₀ CFU/mL of sample higher than the reference methodology, but this can be explained by the different nature of the methodology, media needs, and experimental execution, without affecting the comparability of the biomapping data. The bioMérieux Tempo^® Semi-Automated System can be used for the quantification of microbial indicators in biomapping studies conducted with meat and poultry samples collected at different stages during processing.

Keywords: aerobic plate counts, coliform counts, lactic acid bacteria counts, microbial enumeration methods, Tempo System

110 BIOMAPPING OF PATHOGEN AND INDICATOR MICROORGANISMS AT DIFFERENT STAGES DURING CHICKEN PROCESSING WITH AND WITHOUT CHEMICAL INTERVENTIONS TO IDENTIFY STRATEGIC INTERVENTION POINTS AND DEVELOP STATISTICAL PROCESS CONTROL PARAMETERS FOR FOOD SAFETY MANAGEMENT

D. R. Chavez^1*, R. L. Bueno¹, J. F. DeVillena¹, D. A. Vargas¹, D. E. Casas¹, M. M. Brashears¹, and M. X. Sanchez-Plata¹, ¹International Center for Food Industry Excellence, Texas Tech, Lubbock, Texas, USA, *daniela.r.chavez@ttu.edu

Objectives: The purpose of this study was to develop product microbial baselines at various locations throughout a commercial poultry processing facility operating under the New Poultry Inspection System under high versus low chemical intervention schemes to establish statistical process control thresholds for food safety management and regulatory compliance.

Materials and Methods: The experimental design consisted of a completely randomized design with chemical concentration level as a fixed effect at each stage of the poultry processing chain. Treatments consisted of antimicrobial concentration usually ran by the processing plant (CX) (100–400 ppm of peroxyacetic acid and 50 ppm of total chlorine) and reduced chemical concentration (RC). Nine locations throughout the processing line were sampled, including live receiving (LR), rehanger (RH), post evisceration (M), post-Cropper (C), post-neck breaker (NB), inside-outside bird wash one (IOBW1), inside-outside bird wash two (IOBW2), pre-chill (PRE), post-chill (PC), and wing parts (WINGS). At each location, 10 rinsate samples were taken per repetition for CX and RC treatments, 5 per shift. A total of 810 samples were taken during a 7-mo period. Aerobic counts and Enterobacteriaceae (EB) counts were determined by the Tempo^® system following manufacturer instructions. Salmonella counts and prevalence were determined using SalQuant^TM and BAX^® System Real-Time Salmonella assays, respectively. All counts were transformed to Log CFU/mL of rinse, and statistical analysis was conducted to determinate differences between CX and RC treatment at each location with 0.05 probability threshold using RStudio, version 4.04. When parametric assumptions were not met, the Wilcoxon rank sum test was performed.

Results: Aerobic counts were not different (P > 0.05) between CX and RC treatments at RH, M, and C locations. Counts in NB, IOBW1, IOBW2, PRE, PC, and WINGS showed a difference between treatments with a mean difference of 0.39 Log CFU/mL, where reduced chemical conditions show greater counts. For EB counts, M counts had significant difference between treatments with a mean difference of 0.85 Log CFU/mL, with higher concentration in CX. On average, RC treatment led to higher counts at NB, IOBW1, IOBW2, PRE, and WINGS locations. No difference (P > 0.05) were found in RH, C, and PC locations. In this study, 200 of 810 samples were suitable for enumeration using the BAX^® System SalQuant™, the majority found at LR. Salmonella counts were different (P < 0.05) in all sampling points. The RC treatment led to greater counts with an average difference of 0.37 Log CFU/mL.

Conclusion: Pathogen quantification can result in appropriate risk assessment where chemical intervention can be targeted to stages with higher pathogen concentrations. This study provides evidence for the application of reduced chemical schemes in different stages of processing, tailoring interventions for higher risk areas. The development of biomapping baselines will result in statistical process control analysis to support food safety management decision-making. Nonparametric statistical process control can be approached to more representatively use pathogen prevalence and quantification data together, resulting in more educated decisions than using solely prevalence data.

Keywords: antimicrobial interventions, biomapping, New Poultry Inspection System, Salmonella quantification, statistical process control

111 QUANTIFICATION OF SALMONELLA AND INDICATOR MICROORGANISMS FOR BIOMAPPING AT DIFFERENT STAGES IN A PORK PROCESSING FACILITY OPERATING UNDER NEW SWINE INSPECTION AND FEATURING A BIO-FURNACE CABINET

R. L. Jimenez^1*, R. L. Bueno², D. A. Vargas², D. E. Casas², M. E. Miller², M. M. Brashears², M. X. Sanchez-Plata², and International Center for Food Industry Excellence (ICFIE), Texas Tech University, Lubbock, Texas, USA, ¹Animal and Food Sciences, Texas Tech University, Wolfforth, Texas, USA; ²Animal and Food Sciences, Texas Tech University, Lubbock, Texas, USA, *reagan.brashears@ttu.edu

Objectives: The purpose of this study was to develop a quantitative baseline of indicator microorganisms and Salmonella by biomapping microbial changes through a pork production process with a bio-furnace cabinet.

Materials and Methods: A 10-wk study was conducted to collect 5 samples at each of 11 locations throughout a commercial pork processing facility (n = 550). Sampling locations were post-scalding, after bio-furnace, before final rinse, after final rinse, and post-chilling, and final products were boneless picnic, belly trim, butt trim, loin trim, and advanced meat recovery (AMR) product. Swab samples were taken at the indicated harvest locations while 2-pound samples were collected for trim and ground product. Samples were collected using the protocols for Whole Pork Cuts and Comminuted Pork Aseptic Grab Sample Not in Final Packaging. Swab and product samples were immediately chilled and shipped overnight. Swab and trim samples were prepared utilizing BAX^® MP for indicators aerobic plate count (APC; Enterobacteriaceae [EB], and generic Escherichia coli [EC]). The samples were analyzed for indicator enumeration with the BioMerieux Tempo^®. Salmonella prevalence and enumeration was evaluated using the BAX^® System Real-Time Salmonella and the SalQuant™ methodology. Microbial counts were converted to Log10 CFU/sample.

Results: Total APC were reduced from 4.4 Log₁₀ CFU/ sample on carcasses post-scalding to less than 2.8 Log₁₀ CFU/sample post-chilling. APC counts ranged from 2.1 to 3.1 Log₁₀ CFU/sample on trim, with AMR having the highest count at 3.3 Log₁₀ CFU/sample. Results for both EB and EC were relatively low. EB and EC were detectable in select sampling locations, while APC was countable at all locations. EB counts were found the highest on the post-scalding samples, and none were quantifiable after post-chilling. Belly trim, butt trim, and loin trim along with AMR all had approximately 1–2 Log₁₀ CFU/sample of EB post-chilling. EC was quantifiable on post-scalding samples, but not at any other point in the process after the bio-furnace cabinet. Salmonella counts followed a similar pattern as EB. On the harvest floor, Salmonella was present at approximately 2 logs at all points until post-chilling samples. After chilling, Salmonella was not quantifiable on the carcass. However, there was some quantifiable Salmonella at 1.8–4.1 Log₁₀ CFU/sample present on AMR and belly trim, respectively, after chilling, thus indicating the need for interventions during further processing.

Conclusion: A quantitative microbial biomap was developed in a large USDA-inspected pork processing plant after the implementation of the New Swine Inspection System. This study shows that indicators and Salmonella levels were reduced through the process and not detected after chilling, demonstrating significant control with final reductions occurring in the bio-furnace in this study. However, in trim and AMR samples, both Salmonella and indicators were detected and quantifiable at certain points, indicating the need for interventions after carcass processing. The use of a rapid polymerase chain reaction–based enumerative method for pathogens, in conjunction with indicator levels, provides the pork industry with a tool for data-driven decisions to target points of concern in the process, establish statistical control thresholds, and mitigate the risk to public health of foodborne illness.

Keywords: microbial indicators, New Swine Inspection System, pork processing plant, Salmonella

112 QUANTITATIVE BIOMAPPING OF SALMONELLA AND INDICATOR ORGANISMS THROUGHOUT A PORK PROCESSING LINE TO ESTABLISH STATISTICAL PROCESS CONTROL PARAMETERS FOR FOOD SAFETY MANAGEMENT

R. L. Bueno^1*, M. M. Brashears¹, R. L. Jimenez¹, D. A. Vargas¹, D. E. Casas¹, M. F. Miller¹, and M. X. Sanchez-Plata¹, ¹Animal and Food Sciences, Texas Tech University, Lubbock, Texas, USA, *rossy.bueno@ttu.edu

Objectives: The purpose of this study was to develop a baseline based on quantification of indicator organisms and Salmonella by biomapping through the processing chain from harvest to final product within a commercial pork processing establishment to demonstrate microbial control in pork processing operations implementing the New Swine Inspection System.

Materials and Methods: Five individual samples, including harvest swabs, pork trim, and ground pork, were collected at 13 sampling locations (Harvest: Gambrel Table, After Polisher, Before Final Rinse, After Final Rinse Post Snap Chill, and After Peracetic Cabinet; Trim: Boneless Picnic, Belly Trim, Neck Trim, and Loin Trim; Further Process: Advanced Meat Recovery, Ground Brick Trim, and Sausage Links), over a 10-wk period (n = 650). Swabs were collected on the processing line; trim and further process samples consisting of 2 pounds were immediately chilled and shipped overnight to the International Center for Food Industry Excellence (ICFIE) Food Microbiology Laboratory at Texas Tech University. All samples, except ground products, were prepared utilizing a single enrichment source (BAX^® MP) for indicator organisms (aerobic count, Enterobacteriaceae [EB], and Escherichia coli [EC]). Indicators were enumerated using the bioMérieux TEMPO^®. Salmonella prevalence and enumeration were determined with the BAX^® System Real-Time Salmonella and SalQuant™, respectively. Microbial counts were converted to Log₁₀CFU/mL(g) and Log₁₀CFU/sample prior to statistical analysis.

Results: All indicator microorganisms were significantly reduced at the harvest floor (P < 0.001), from Gambrel Table to After Peracetic Cabinet. The reduction at Harvest was 2.27 Log₁₀CFU/mL for aerobic counts, 2.46 Log₁₀CFU/mL for EB counts, and 2.24 Log₁₀CFU/mL for EC counts. Trim sample values fluctuated based on cut, with the highest aerobic count found at Neck Trim (2.83 Log₁₀CFU/g). Further process samples showed the highest aerobic count in Sausage with a mean of 5.28 Log₁₀CFU/g. EB counts in Sausage (3.19 Log₁₀CFU/g) were increased, compared with the reduction observed at the end of harvest and throughout trim processing. EC counts showed a similar trend to EB counts, with the highest value found in Sausage Links (1.60 Log₁₀CFU/g). Statistical microbial process control parameters were also developed for each of the indicator microorganisms, using the sample mean ($\overline{X}$), the lower control limit, and the upper control limit with ±3σ at each sampling location. For Salmonella prevalence, a total of 126/650 samples were found positive (19%). From those positive samples, 52 samples (41%) were suitable for enumeration using the BAX^® System SalQuant™, the majority detected at the Gambrel Table location. The Salmonella counts at Gambrel Table, After Polisher, Before Final Rinse, and After Final Rinse locations ranged from <1 CFU (limit of enumeration) to 4.02 Log₁₀CFU/sample. There was an average Salmonella reduction of 1.87 Log₁₀CFU/sample on the harvest floor. For trim samples, Salmonella counts were highest for Boneless Picnic (2.87 Log₁₀CFU/sample).

Conclusion: This study provides evidence for the application of emerging technologies for pathogen quantification and indicator levels in pork samples. It provides the basis for developing statistical process control variables based on process biomapping baselines at different stages during processing to support food safety management decision-making for controlling pathogens in pork products and guide process changes and speed line modifications.

Keywords: microbial indicators, New Swine Inspection System, pork processing plant, Salmonella

113 LYTIC BACTERIOPHAGE AND LACTIC ACID AGAINST E. COLI O157:H7 IN MARINATED AND TENDERIZED PORK LOINS

S. Li^1*, H. M. Konoval¹, S. Marecek¹, A. A. Lathrop², and S. Pokharel¹, ¹Animal Science and ²Food Science and Nutrition, California Polytechnic State University, San Luis Obispo, California, USA, *spokhare@calpoly.edu

Objectives: It is evident that pork is an underrecognized source of Shiga toxin–producing Escherichia coli; however, there are multiple studies and documented cases providing evidence for the pork-related Shiga toxin–producing E. coli O157:H7 infections. Thus, E. coli O157:H7 is becoming an increasing concern for the pork industry despite several attempts to eliminate the microorganisms in several critical steps. This study aimed to evaluate the effect of lytic bacteriophages (phage) and lactic acid (LA) as antimicrobials in reducing the presence of E. coli O157:H7 on the surface and internal cores of marinated and tenderized pork loins.

Materials and Methods: E. coli O157:H7 from 3 different sources (hamburger—NFPA 4200, salami—NFPA 4212, and lettuce—NFPA 4217) were maintained on Tryptic Soy Agar throughout the experiment. Locally purchased raw pork loins were sliced into 2"–2½” thick chops (n = 30/replication). Pork chops were inoculated with an E. coli O157:H7 cocktail with a concentration of 10⁶ CFU/mL for 30-min attachment at 4°C. Inoculated chops were marinated for 1 h with 0.35% sodium chloride and 0.45% sodium tripolyphosphate. Marinated pork chops were randomly divided into one of the 5 different treatments (Control, DI water, LA 2.5%, phage 5%, and LA 2.5% + phage 5%) and were tenderized through a manual meat tenderizer. Treatments were applied (10 μL/cm²) to cover the entire meat surface area. Surface swabs (50 cm²) were taken before and after the meat tenderization process. Sterile internal meat cores were homogenized and evaluated for the possible pathogen translocation by plating on CT-SMAC agar. Response variables of interest include surface pathogen attachment, internal pathogen concentration, and meat pH. Pathogen cell count was transferred to log₁₀ CFU per square centimeter or gram prior to the statistical analysis. PROC MIXED procedure of SAS (SAS Institute Inc., Cary, NC) was used as a statistical tool to analyze. Mean separation was done using the DIFF function, which is used to determine significant differences (P < 0.05) among means using analysis of variance.

Results: We hypothesized that the application of LA 2.5% and phage 5% on marinated pork chops would result in the significant reduction of E. coli O157:H7 counts on the surface, and internal cores, whereas the combined treatment would result in an even higher log reduction of the pathogens. With the first replication in hand, the data indicate varied antimicrobial susceptibility patterns of E. coli cocktails in marinated pork loins. Marinated loins treated with phage and LA + phage significantly reduced the surface pathogens after 60 min of cold storage when compared with control. Similarly, phage-treated loins showed a significant reduction of more than 2.40 logs of E. coli (P < 0.05) on the post-tenderized loin surface. However, no difference was observed (P > 0.05) for the post-tenderized surface counts between DI, LA, and LA + phage treated loins. Likewise, no difference (P > 0.05) was observed between phage, DI, and LA treated loins for the number of translocated pathogens from the surface to the internal core after manual tenderization.

Conclusion: E. coli O157:H7–specific phage and LA reduced the number of surface pathogens translocated from the surface to the internal cores and on post-tenderization surface counts for marinated pork loins (60 min).

Keywords: E. coli O157:H7, food safety, lactic acid, lytic bacteriophage, pork

114 APPLICATION OF PREDICTIVE MODELING IN THE VALIDATION OF A HOME-STYLE RESTRUCTURED BEEF JERKY PRODUCT DESIGNED FOR PRODUCTION IN ETHIOPIA

J. Brown^1*, A. Cavallo¹, G. Allen¹, A. Manzoor¹, A. Havelaar^1,2,3, and J. Scheffler¹, ¹Animal Sciences, ²Emerging Pathogens Institute, and ³Food Systems Institute, University of Florida, Gainesville, Florida, USA, *jmscheff@ufl.edu

Objectives: Ethiopia is home to the 10th largest livestock inventory in the world. Despite the availability of livestock, the population still has one of the lowest per capita red meat consumptions in the world. Inefficiencies in the meat supply chain have limited the access to animal-sourced food and demonstrate the need for additional preservation techniques to improve the accessibility of meat. Drying is one of the oldest food preservation methods, involving the addition of salt and removal of water to make a shelf-stable, nutrient-dense, and ideally “safe” product. Pathogens have demonstrated the ability to adapt during a slow drying process, making them more resistant to later heat treatments and complicating process validation. The objective of this study was to quantitatively evaluate the inactivation kinetics of foodborne pathogens during the drying of a restructured beef jerky product in a home-style dehydrator.

Materials and Methods: Challenge studies were performed to evaluate the inactivation of 5 serotypes of Salmonella enterica (Saintpaul, Anatum, Typhimurium, Newport, Dublin), 3 strains of Escherichia coli O157:H7, and 3 strains of Campylobacter jejuni. Berbere, an Ethiopian spice mixture, and salt were added to lean ground beef. Each treatment was inoculated with a cocktail of isolates, formed into strips, and dehydrated for 6 h in a home-style dehydrator (600W). Samples were weighed pre- and post-drying, plated for enumeration at times 0, 1, 2, 3, 4, 5, and 6 h, and water activity was measured at each sampling interval.

Results: The dry-bulb temperature steadily increased for the first 3 h of drying before stabilizing at 61.8°C ± 0.6°C, and the relative humidity stabilized at approximately 10%. Nonlinear predictive models were fitted to the inactivation data revealing an inverse sigmoidal curve for the inactivation of Salmonella and concave downward curves for the inactivation of E. coli O157:H7 and Campylobacter. The predictive models suggest that, after 6 h of drying, a 4.56- and 6.27-log (CFU/g) reduction of Salmonella and E. coli O157:H7 will be achieved, and after 3 h of drying, a 4.32-log (CFU/g) reduction of Campylobacter will be achieved. The shape of these curves suggests the need for a higher wattage dehydrator to either shorten the come-up time or increase the maximum temperature, or both, to reduce the opportunity for Salmonella to desiccate before thermal lethality.

Conclusion: Additional processes to extend the shelf life of animal-sourced foods in Ethiopia will provide consumers with a more convenient and accessible source of protein, as well as provide producers with a secondary avenue to market their product. Predictive models of pathogen inactivation allow producers, in Ethiopia and the United States, to more accurately assess the microbial risk of their product at any point during production.

Keywords: Campylobacter, E. coli, inactivation kinetics, Salmonella, water activity

115 BIOMAPPING OF MICROBIAL INDICATORS ON BEEF CARCASSES, SUBPRIMALS, AND TRIMMINGS THROUGH THE PROCESSING LINE AFTER APPLICATION OF MULTIPLE ANTIMICROBIAL INTERVENTIONS

D. E. Casas^1*, D. A. Vargas¹, R. L. Bueno¹, A. Echeverry¹, M. X. Sanchez-Plata¹, M. M. Brashears¹, and M. F. Miller¹, ¹Animal and Food Sciences, Texas Tech University, Lubbock, Texas, USA, *diego.casas@ttu.edu

Objectives: The study objective was to determine load reductions of indicator microorganisms after application of antimicrobial interventions through the beef processing line.

Materials and Methods: EZ-Reach™ swabs pre-hydrated with 25 mL buffered peptone water were used to collect beef samples before and after intervention treatments on a 100 cm² area in the foreshank area of the carcass at 4 processing stages in a commercial operation: hot carcass just before entering the hot box (n = 540), cold carcass after 24 h of chilling (n = 300), subprimals just before packaging (n = 972), and beef trimmings coming off of the fabrication floor (n = 540). A total of 6 subprimals, brisket, shoulder clods, top butts, knuckles, loin tails, and chuck rolls, as well as 3 types of trim, shank, chuck, and heel, were evaluated. Unpaired sampling was conducted at every processing stage. Hot carcass intervention consisted of hot water wash with a water temperature of 76°C–87°C followed by a lactic acid spray with a temperature of 43°C–55°C at 2%–5% lactic acid concentration at a pressure ≥15 psi. Cold carcass intervention consisted of a lactic acid spray with solution at 43°C–55°C and 2%–5% lactic acid concentration at ≥15 psi. Subprimal intervention consisted of lactic acid spray with a temperature of 43°C –55°C at 2%–5% lactic acid concentration with a pressure of ≥15 psi. Trim intervention consisted of lactic acid trim submersion with a solution at 43°C–55°C and 2%–5% concentration of lactic acid. Swabs were immediately chilled and shipped overnight to the ICFIE Food Microbiology Laboratory at Texas Tech University. Samples were homogenized in a stomacher at 230 rpm for 1 min, serially diluted, and plated onto 3M^T Petrifilm plates to determine total aerobic plate counts (APC), coliform (CC), and generic E. coli (EC) counts. APC petrifilm were incubated for 48 ± 3 h at 35°C ± 1 °C. The CC/EC petrifilms were incubated for 48 ± 3 h at 35°C ±1°C. CC counts were determined after 24-h incubation. EC counts were determined after 48-h incubation. Microbial counts converted to LogCFU/cm² before statistical analysis.

Results: All indicator microorganisms were significantly reduced at each stage after each intervention (P < 0.05). APC were reduced by 4.59 LogCFU/cm² in hot carcass, 0.68 LogCFU/cm² in cold carcass, and by at least 0.37 LogCFU/cm² in the evaluated subprimals and 0.84 LogCFU/cm² in analyzed trim samples. CC counts were reduced by 4.20 LogCFU/sample in hot carcass, 0.74 LogCFU/sample in cold carcass, at least 0.97 LogCFU/sample in the evaluated subprimals, and 0.81 LogCFU/sample in analyzed trim samples. EC counts were reduced by 4.10 LogCFU/sample in hot carcass, 0.15 LogCFU/sample in cold carcass, at least 1.01 LogCFU/sample in the evaluated subprimals, and 0.65 LogCFU/sample in analyzed trim samples. Final product average counts were 0.61 LogCFU/cm², 0.60 LogCFU/sample, and 0.32 LogCFU/sample for APC, CC, and EC counts, respectively.

Conclusion: Additional interventions in post-chill stages are effective in further reducing indicator microorganism counts. A multiple hurdle approach of applying different interventions can continuously reduce indicator microorganisms through the beef processing chain. The interventions applied at every step effectively reduced indicator microorganisms, thus potentially improving the safety of the final product.

Keywords: antimicrobial, beef processing plant, lactic acid, microbial indicators

116 NOVEL OZONE GENERATION TECHNOLOGY (BIO-SAFE) INTERVENTION COMPARED WITH LACTIC ACID IN VARIETY MEATS IN A BEEF PROCESSING PLANT

D. A. Vargas^1*, D. E. Casas¹, A. Echeverry¹, M. F. Miller¹, M. M. Brashears¹, and M. X. Sanchez¹, ¹Animal Science, Texas Tech University, Lubbock, Texas, USA, *david.vargas95@hotmail.com

Objectives: The purpose of this study was to compare the antimicrobial efficacy of an aqueous ozone intervention and a lactic acid solution on natural microbiota of variety meats in a commercial beef processing plant.

Materials and Methods: EZ-Reach™ swabs pre-hydrated with 25 mL of buffered peptone water were used to collect 500 cm² area samples before and after ozone and lactic acid intervention application for 3 different variety meats (head, heart, and liver). Lactic acid intervention parameters included a spray treatment with a temperature of 43°C–55°C at 2%–4% lactic acid concentration and spray pressure ≥15 psi. The aqueous ozone intervention spray had a concentration of 1.5–2.3 ppm, an oxidation-reduction potential between 700 and 900 mV with a spray pressure ≥20 psi, and an incoming water maintained at 10°C–24°C. The ozone intervention consisted of one cabinet with 44 nozzles delivering 12.8 gpm with 18 s of contact time. Each repetition included 54 samples per variety meat and antimicrobial, 27 before and 27 after intervention, for a total of 162 samples per repetition. Swab samples were immediately chilled and shipped overnight to the ICFIE Food Microbiology Laboratory at Texas Tech University for microbial analysis. Samples were stomached at 230 rpm for 1 min, and for each variety meat, 3 individual samples were composited into one. Serial dilutions and enumeration of total aerobic bacteria (aerobic plate count) and Escherichia coli were performed on each composite. Counts were transformed into Log CFU/cm², and statistical analysis was conducted to determine differences between before and after intervention with 0.05 probability threshold. A total of 6 repetitions were conducted throughout the whole study, where the lactic acid treatment occurred 1 full year before plant modifications using the ozone delivery system. This study compares microbial performance year-to-year differences under modified antimicrobial schemes.

Results: Aerobic plate count and E. coli count were transformed to Log CFU/sample for statistical analysis as counts were considerably low when analyzed on a Log CFU/cm² basis (detection limit = 0.002 CFU/cm²). Microbial counts for both microorganisms evaluated were significantly reduced (P < 0.001) after lactic acid immersion (2%–5%) and ozone intervention for all variety meats with the exception of ozone intervention in E. coli counts in heart samples. Aerobic plate counts after lactic acid intervention were reduced on average by 1.73, 1.66, and 1.50 Log CFU/sample in head, heart, and liver, respectively. Samples collected under the ozone intervention scheme showed that counts were reduced on average by 1.66, 0.52, and 1.20 Log CFU/sample. E. coli counts after lactic acid intervention were reduced on average by 0.96, 0.79, and 1.00 Log CFU/sample in head, heart, and liver, respectively, whereas after ozone intervention, counts were reduced on average by 0.75, 0.62, and 1.25 Log CFU/sample.

Conclusion: The aqueous ozone antimicrobial scheme proved to be promising as an intervention for the reduction of indicator levels in variety meats. These findings suggest that bio-safe ozone intervention may play a competitive role as lactic acid applications for reducing bacterial load on variety meats, thus contributing to food safety control.

Keywords: beef variety meats, lactic acid, microbial indicators, ozone intervention

117 STORAGE TEMPERATURE AND DURATION IMPACT SPOILAGE ORGANISM GROWTH IN VACUUM-PACKAGED BEEF STRIP LOINS

A. K. Moore^1*, M. S. Hernandez¹, D. A. Vargas¹, D. R. Woerner¹, J. C. Brooks¹, and J. F. Legako¹, ¹Animal and Food Science, Texas Tech University, Lubbock, Texas, USA, *alexk.moore@ttu.edu

Objectives: The objective of this study was to evaluate the influence of storage temperature, duration, and their interaction on spoilage organism growth.

Materials and Methods: Paired USDA Choice strip loins (Institutional Meat Purchase Specifications #189; n = 60) were collected from a commercial beef processing facility. Each carcass was assigned to a storage temperature (−2°C, 0°C, 4°C). Strip loins were portioned into half loins and assigned to an aging duration (14, 28, 42, 56 d). Loins were aged in commercial upright refrigerators, and temperatures were monitored with data loggers. At each aging interval, the vacuum packaging was opened to expose the cut surface of the longissimus lumborum. The cut surface was swabbed using pre-hydrated buffered peptone water swabs and a 50 cm² template. Lactic acid bacteria (LAB; mesophilic), Enterobacteriaceae (EB; mesophilic), and aerobic plate counts (mesophilic [M-APC], psychrotrophic [P-APC]) were spoilage organisms of interest. LAB, EB, and M-APC were enumerated using the TEMPO System. P-APC were enumerated, in duplicate, on APC Petrifilms. Serial dilutions were performed using buffered peptone water tubes, as necessary. Data were log₁₀ transformed for statistical analysis. The detectable limit was 0.02 CFU/cm². Data were analyzed as a split-plot in which storage temperature served as the whole plot and aging duration served as the subplot. An alpha of P < 0.05 to determine significance.

Results: Storage temperature × aging duration interactions were observed for all spoilage organisms (P < 0.001). Loins aged for 42 d at 4°C had the greatest EB counts compared with all other treatments (P < 0.001). EB counts in loins aged for 28 and 56 d at 4°C were similar (P > 0.05). Within the 4°C environments, loins aged for 14 d possessed the lowest EB counts. EB growth was similar between loins aged at –2°C and 0°C regardless of duration (P > 0.05). M-APC growth was the lowest in loins aged for 14 d at −2°C (P < 0.001). Loins aged for 28 d and 42 d at either 0°C or 4°C possessed increased M-APC growth (P < 0.001). Similar to M-APC, LAB growth was lowest in loins aged for 14 d at −2°C or 0°C (P < 0.001). Loins aged for 28, 42, and 56 d at 4°C and 42 d at 0°C possessed the greatest LAB microbial loads (P < 0.001). P-APC growth was greater in loins aged at 4°C compared with loins aged in −2°C or 0°C (P < 0.001). Loins aged for 14 d at 4°C were similar to loins aged for 42 or 56 d at −2°C (P < 0.001).

Conclusion: These data indicate that storage temperature influences the growth of spoilage organisms at different aging durations. Aging beef subprimals in colder environments mitigates spoilage organism growth during extended aging.

Keywords: beef, shelf life, spoilage organisms, temperature, wet aging

118 TANDEM MASS TAG LABELING-BASED ANALYSIS OF BISON MUSCLES TO CHARACTERIZE MUSCLE-SPECIFIC PROTEOME CHANGES DURING AGING

M. M. Hasan^1*, M.-U. Rashid², S. P. Suman³, H. Perreault⁴, J. Paliwal⁵, and A. Rodas-Gonzalez⁶, ¹Food and Human Nutritional Sciences and ²Medical Microbiology and Infectious Diseases, University of Manitoba, Winnipeg, Canada; ³Animal and Food Sciences, University of Kentucky, Lexington, Kentucky, USA; ⁴Chemistry, ⁵Biosystems Engineering, and ⁶Animal Science, University of Manitoba, Winnipeg, Canada, *hasanmm@myumanitoba.ca

Objectives: The objective of the study was to examine the variations in sarcoplasmic proteome profile in bison longissimus lumborum (LL; color-stable) and psoas major (PM; color-labile) muscles during postmortem aging periods (2 d, 7 d, and 14 d) using tandem mass tag (TMT) isobaric labeling coupled with liquid chromatography–mass spectrometry for the segregation of muscles with muscle-specific inherent color stability.

Materials and Methods: Six (n = 6) LL (striploins) and 6 (n = 6) PM (tenderloins) muscles from A1 grade bison carcasses were collected from a federally inspected slaughter plant within 48 h postmortem. Each muscle portion was sub-sampled (15–20 g) for the sarcoplasmic proteomic analysis at 2 d postmortem (baseline) and vacuum packaged and stored immediately at −40°C. The remaining muscle portions were equally divided into 2 parts and stored at 2°C for an aging period of 7 and 14 d. At the end of each aging period, sample for proteomic analysis was collected from each muscle, vacuum packaged, and stored at −40°C for subsequent analysis. TMT labeling based proteomic analysis was performed coupled with liquid chromatography–tandem mass spectrometry. After collecting the mass spectrometry data, tryptic peptides were searched and identified against the bison protein database using X! Tandem software.

Results: A total of 576 proteins were identified in both bison LL and PM muscles, of which 96 proteins were found differentially abundant (fold change > 1.5, P < 0.05) from the 3 comparisons between muscles during postmortem storage periods (PM vs. LL at 2 d, 7 d, and 14 d). Among those proteins, the most important identified protein groups based on function are related to electron transport chain (ETC), tricarboxylic acid cycle, ATP production and transport, carbohydrate metabolism (mostly glycolytic enzymes), lipid or fatty acid (FA) degradation, chaperones, oxygen transport, calcium signaling, muscle contraction, and protein synthesis. In LL muscles, the dehydrogenase proteins of ETC, tricarboxylic acid cycle, FA oxidation, carbohydrate metabolism, and ATP transport proteins were overexpressed or upregulated during aging than PM. On the other hand, the proteins of carbohydrate metabolism (glycogen phosphorylase, phosphoglucomutase-1, adenylate kinase isoenzyme-1) related to ATP utilization were downregulated in LL muscles compared with PM. During comparisons of PM versus LL muscles, protein-protein interactions showed specific networks at 2 d (ETC, FA oxidation, and muscle contraction), 7 d (muscle contraction), and 14 d (carbohydrate metabolism, FA oxidation, and muscle contraction). The results clearly indicate that the dehydrogenase enzymes responsible for reducing equivalents and ATP production were highly expressed in LL muscles resulting in oxidative stability and subsequent meat color stability. Moreover, the glycolytic proteins involved in ATP utilization were downregulated in LL muscles, reflecting more color stability.

Conclusion: The TMT-based proteomic analysis showed a clear segregation of 2 bison major muscles wherein PM showed lower color stability compared with LL. To the best of our knowledge, this is the first attempt to compare the proteomic profile of bison LL and PM muscles from different storage periods. Therefore, this isobaric tag-based analysis was able to uncover the proteomic profile of bison muscles with inherent color stability.

Keywords: color stability, segregation, proteomics, sarcoplasmic proteins, isobaric tags, liquid chromatography–mass spectrometry

119 MYOGLOBIN POST-TRANSLATIONAL MODIFICATIONS INFLUENCE FRESH BEEF COLOR STABILITY

Y. Wang^1*, S. P. Suman¹, G. Rentfrow¹, S. Li¹, J. Chen², and H. Zhu², ¹Animal and Food Sciences and ²Proteomics Core Facility, University of Kentucky, Lexington, Kentucky, USA, *wang.10408@buckeyemail.osu.edu

Objectives: Post-translational modifications (PTM) play a fundamental role in regulating biological processes. The complex relationship between PTM of muscle proteins and meat quality has become increasingly evident recently. Nonetheless, investigations have yet to be undertaken to characterize myoglobin PTM and their role in fresh meat color stability. Therefore, the objectives of the current study were to identify the sites of myoglobin PTM in postmortem beef longissimus lumborum (LL) muscle during aging and to evaluate their influence on fresh beef color stability.

Materials and Methods: Beef LL muscles collected from right side of 9 (n = 9) beef carcasses (USDA Choice; A maturity; 24 h postmortem aging) were divided into 4 equal-length sections. The muscle sections were vacuum packaged and randomly assigned to wet aging at 2°C for either 0, 7, 14, or 21 d. At the end of each wet-aging period, the muscle sections were removed from the vacuum package and fabricated into four 1.92-cm-thick steaks. One steak from each muscle section allotted for proteome analyses was immediately vacuum packaged and frozen at –80°C until use. The remaining 3 steaks assigned for evaluation of instrumental color and biochemical evaluation were aerobically packaged and assigned to refrigerated storage (2°C) in the darkness for either 0, 3, or 6 d. Myoglobin PTM were analyzed using two-dimensional electrophoresis and tandem mass spectrometry. The instrumental color and biochemical properties were analyzed as a split-plot design with aging time as a whole-plot factor and storage day as a subplot factor. Carcass was considered as random effect. The data were analyzed using PROC MIXED procedure in SAS (SAS Institute Inc., Cary, NC), and the differences among the means were detected using the least significant differences at a P < 0.05 level.

Results: Aging influenced fresh beef color attributes; surface redness (a* value), color stability (R630/580), and myoglobin concentration decreased (P < 0.05) upon aging. Image analysis of two-dimensional gels identified 6 spots as myoglobin, with similar molecular weight (17 kDa) but different isoelectric pH, indicating that myoglobin was post-translationally modified. Tandem mass spectrometry identified multiple PTM (phosphorylation, methylation, carboxymethylation, acetylation, and hydroxynonenal alkylation) in the 6 myoglobin spots. The amino acid residues susceptible to phosphorylation were identified as serine, threonine, and tyrosine, whereas methylation, acetylation, and carboxymethylation were detected in lysine and arginine residues. Additionally, distal histidine (histidine 64), which is critical to heme stability, was readily modified by hydroxynonenal alkylation. Furthermore, myoglobin PTM sites increased with aging time from day 0 to day 14, whereas they decreased afterward. The decrease in number of PTM from day 14 to day 21 was possibly due to the decrease in myoglobin concentration.

Conclusion: Myoglobin in beef LL muscle undergoes PTM during aging. These PTM compromise myoglobin redox stability by adding modifying groups to amino acid residues—especially those close to the hydrophobic heme pocket—and therefore accelerate myoglobin oxidation and beef discoloration. These in situ myoglobin PTM could be utilized as novel biomarkers for color stability in muscle foods.

Keywords: meat color, myoglobin, post-translational modifications

120 HIGH PULMONARY ARTERIAL PRESSURE IN STEERS AT MODERATE ALTITUDE AFFECTS EARLY POSTMORTEM MITOCHONDRIA FUNCTIONALITY

C. Zhai^1*, L. C. Li Puma², A. J. Chicco², A. Omar², R. J. Delmore¹, I. Geornaras¹, S. E. Speidel¹, T. N. Holt³, M. G. Thomas¹, R. M. Enns¹, and M. N. Nair¹, ¹Department of Animal Sciences, ²Department of Biomedical Sciences, and ³Department of Clinical Sciences, Colorado State University, Fort Collins, Colorado, USA, *chaoyu.zhai@colostate.edu

Objectives: Pulmonary hypertension is a noninfectious disease of cattle at altitudes >1,524 m (5,000 ft). Mean pulmonary arterial pressure (PAP) is used as an indicator for pulmonary hypertension in cattle. High-PAP cattle (≥50 mmHg) entering the feedlot at moderate elevations have lower feed efficiency as compared with low-PAP cattle (<50 mmHg). The longissimus lumborum (LL) steaks from high-PAP steers have lower color and lipid stability than those from low-PAP steers during retail display. Mitochondria can affect animal production efficiency, and their functionality in postmortem muscle contributes to meat color and tenderness development. However, the effect of PAP on muscle mitochondria in beef cattle has not been investigated. Therefore, the objective of this study was to examine the effect of PAP on beef mitochondrial function during the early postmortem period.

Materials and Methods: Mitochondrial function and oxidative phosphorylation (OXPHOS) protein abundance of LL muscle from high-PAP (98 ± 13; n = 5) and low-PAP (41 ±3 ; n = 6) fattened Angus steers (i.e., live weight of ∼600 kg) were evaluated during early postmortem period (2 h and 48 h postmortem) by a split-plot design. Data analysis was performed using R with the lme4 package as a mixed model, where PAP score (high or low), postmortem time, and their interactions were the fixed effects, and random effect was individual steer. The differences between least-squares means (P < 0.05) were determined by Tukey’s multiple comparison.

Results: A PAP × postmortem-time interaction (P < 0.05) was observed in the proton leak-associated respiration (supported by high NADH) and OXPHOS-linked respiration (supported by pyruvate + malate). This suggested that high-PAP muscle tended to have a greater respiratory capacity at 2 h postmortem and a faster decline in mitochondrial respiratory capacity from 2 h to 48 h postmortem than low-PAP muscle. In addition, there was a decline (P < 0.05) in OXPHOS-linked respiratory capacities (supported by maximal delivery of NADH and NADH + succinate), as well as the oxygen reductase capacity of complex IV in LL muscle from 2 h to 48 h postmortem, which suggested that the maximal respiratory capacity of LL declined after animal slaughter independent of PAP. Furthermore, muscle OXPHOS protein expression was greater in low-PAP than high-PAP animals (P < 0.05) regardless of postmortem time, which suggested a greater mitochondria content in low-PAP muscle and a potential shift in muscle fiber type of the LL muscle.

Conclusion: High PAP caused a lower OXPHOS efficiency and a greater fuel oxidation rates under conditions of low ATP demand in beef LL muscle. This could explain the lower feed efficiency in high-PAP feedlot cattle compared with low-PAP counterparts. Mitochondrial integral function declined faster in high-PAP compared with low-PAP muscle early postmortem, which could be leading to the lower color and lipid stability of high-PAP LL during retail display. Pulmonary arterial hypertension could also decrease type I/type II muscle fiber ratio in skeletal muscle, which needs to be investigated further.

Keywords: longissimus lumborum, mitochondrial function, pulmonary hypertension

121 AN INVESTIGATION OF THE RELATIONSHIP BETWEEN SARCOMERE LENGTH AND MEAT TENDERNESS AND A NOVEL WAY TO MEASURE SARCOMERE LENGTH

C. Velasco Ayala^1*, P. Hammond¹, A. Welter¹, C. Chun¹, T. O’Quinn¹, E. Boyle¹, E. Geisbrecht², and M. D. Chao¹, ¹Department of Animal Sciences & Industry and ²Department of Biophysics and Biochemistry, Kansas State University, Manhattan, Kansas, USA, *carovelayala@gmail.com

Objectives: Sarcomere length (SL) has long been considered as an indicator for meat tenderness because it determines the level of muscle contraction. Historically, SL is commonly measured by the laser diffraction method proposed by Cross et al., 1981. Although this method is widely accepted, it is labor intensive and could potentially result in serious damage in eyesight; furthermore, it also lacks tangible proof of actual measurement of SL. Therefore, the objective of the study was to develop a novel and convenient way to measure SL by immunostaining powdered meat, as well as to investigate the relationship between Warner-Bratzler shear force (WBSF) and SL of 8 different beef muscles with 2 aging periods.

Materials and Methods: Eight muscles were collected from 10 USDA choice beef carcasses: supraspinatus (SS), longissimus thoracis (LT), rectus femoris (RF), rectus abdominis (RA), triceps brachii (TB), semitendinosus (ST), gluteus medius (GM), and pectoralis profundus (PP). The muscles were cut into steaks and assigned to a 2- or 21-day aging period (n = 160). Each steak was pulverized in liquid nitrogen prior to analysis. A few meat speckles from each sample were placed on a microscope slide and incubated with anti-α-actinin as a primary antibody, followed by incubating with Alexa-Flour Plus 488 as the secondary antibody. Finally, the slide was imaged using an upright confocal microscope with a 63x/1.4 oil objective. A total of 30 sarcomeres were measured and averaged for each sample. Additionally, each sample’s tenderness was measured by the WBSF method. A correlation analysis was performed to elucidate the relationship between SL and WBSF.

Results: There was no interaction between muscle and aging time for SL (P > 0.10), but a main effect was found for muscle (P < 0.05). PP (2.47 μm) and RA (2.46 μm) had the longest SL, followed by SS (2.24 μm), TB (2.09 μm), RF (2.01 μm), and ST (1.88 μm), with LT (1.75 μm) and GM (1.65 μm) having the shortest sarcomeres among all (P < 0.01). In addition, PP (6.93 kg) had the highest WBSF, followed by SS (5.37 kg), ST (5.27 kg), GM (4.62 kg), RA (4.53 kg), TB (4.17 kg), RF (3.97 kg), and finally LT (3.72 kg) with the lowest WBSF among all (P < 0.01). A positive correlation coefficient (r) was only found between SL and WBSF for SS (r = 0.50; P < 0.05), but not for any other muscle utilized in this study. Finally, an overall positive relationship between SL and WBSF was found for all muscles combined and measured as a whole (r = 0.39, P < 0.01).

Conclusion: Measuring SL by staining α-actinin is feasible, and it yields comparable results to other studies that reported on SL in these same muscles. It is interesting to point out that tougher muscles tended to have longer sarcomeres. However, no clear relationship was found between SL and WBSF on an individual muscle basis.

Keywords: beef, sarcomere length, tenderness, Warner-Bratzler shear force

122 VOLATILE COMPOUNDS AND AMINO ACID CONTENT ARE CORRELATED WITH OFF-FLAVOR INTENSITY OF DRY- AND WET-AGED USDA PRIME AND CHOICE STRIP LOINS AGED FOR 21 AND 42 D

A. S. De Mello^1*, A. Cavender¹, F. Giotto¹, T. Dinh², and M. Teglas¹, ¹Agriculture, Veterinary, and Rangeland Sciences, University of Nevada, Reno, Nevada, USA; ²Animal and Dairy Sciences, Mississippi State University, Starkville, Mississippi, USA, *ademello@unr.edu

Objectives: Dry aging beef has been associated with a process that enhances eating experience by improving flavor. Flavor perception depends on a multisensory integration led by chemical compounds that are detected via olfactory–gustatory interactions. Amino acids are part of a large pool of reactive components that may directly or indirectly affect flavor by reacting with reducing sugars to form Maillard reaction products and Strecker degradation products that impact meat flavor. In this study, we identified volatiles and amino acids from dry- and wet-aged USDA Prime and Choice strip loins aged for 21 and 42 d that may be associated with off-flavor intensity.

Materials and Methods: Forty-eight short loins (Institutional Meat Purchase Specifications #174; 24 Prime and 24 Choice) were arranged to a 2 × 2 × 2 factorial design including aging method (dry and wet), USDA quality grade (Choice and Prime), and aging time (21 and 42 d) as fixed effects. Dry-aged samples were held at 2°C ± 2°C, and humidity was maintained at 80%–85% and air speed at 2 m/s. Wet-aged samples were stored under the same temperature in their original vacuum-sealed bag. Volatiles were captured by using an SPME fiber in the headspace of a vial containing cooked steak aliquots. Fibers were desorbed on a Shimadzu GCMS-QP2010 SE (Shimadzu Co., Kyoto, Japan), and compounds were identified by retention time, target, and qualitative ions and quantified using known standards in 5-point calibration curve. Amino acids were also identified and quantified by GCMS using an Agilent 7890A GC System coupled to an Agilent 5975C inert XL MSD with triple-axis mass detector (Agilent Technologies, Santa Clara, CA). Amino acids were identified and quantified using standards provided with the EZfaast Amino Acid kit (Phenomenex^® Inc., Torrance, CA). Correlations presented in this report were obtained by evaluating volatile and amino acid profile and off-flavor intensity data previously reported by the authors during the RMC in 2020 and 2021. Data were analyzed using PROC CORR of SAS (SAS Institute Inc., Cary, NC).

Results: Overall, pentanal was positively and acetoin negatively correlated with off-flavor intensity. Pentanal, alanine, and proline were positively correlated to off-flavor intensity in Choice-graded strip loins. In USDA Prime loins, acetoin was negatively correlated with off-flavor intensity and ornithine negatively correlated. When loins were dry aged, acetoin, sum of ketones, and sarcosine were negatively correlated to off-flavor intensity. Pentanal, aspartic acid, methionine, and proline were positively correlated with off-flavor intensity when loins were wet aged. When loins were aged for 21 d, 2,3-butanedione and sum of ketones were negatively correlated to off-flavor, whereas for loins aged for 42 d, pentanal was positively and acetoin was negatively correlated with off-flavor intensity.

Conclusion: Pentanal seems to be the most important volatile associated to off-flavor intensity, whereas lower levels of acetoin seem to decrease off-flavor perception. Some amino acids, including alanine, methionine, and proline, may also be associated to off-flavor intensity.

Keywords: amino acids, beef, dry aging, volatiles

123 LIPID CONTENT OF GROUND BEEF INFLUENCES THE RATE OF DISCOLORATION AND LIPID OXIDATION DURING SIMULATED RETAIL DISPLAY

Y. Wang^1* and B. M. Bohrer¹, ¹Animal Sciences, The Ohio State University, Columbus, Ohio, USA, *wang.10408@buckeyemail.osu.edu

Objectives: Lipid oxidation and myoglobin oxidation result in the development of oxidative rancidity and discoloration in meat, respectively. Previous investigations have documented the potential interrelationship between the 2 oxidative processes; however, applied research that directly investigates the interactive roles of these processes is limited. Thus, the objective of the current study was to examine the relationships between lipid content, lipid oxidation, and discoloration rate of ground beef during a simulated retail display.

Materials and Methods: Beef inside rounds (Institutional Meat Purchase Specifications #168) and bone-in ribs (Institutional Meat Purchase Specifications #107) from the right side of steer carcasses (n =138) were utilized in this study. For each carcass, 2 grinds of ground beef were manufactured by grinding cubes of inside round and subcutaneous fat from bone-in ribs through a Sirman Master 90 Y12 meat grinder at targeted levels of 10% and 25% fat. A total of 276 batches of 4.54 kg of ground beef were manufactured, and 6 patties were prepared from each batch. Two patties from each batch that were assigned for evaluation of lipid content by Soxhlet extraction, as well as initial lipid oxidation with thiobarbituric acid reactive substances assay, were immediately vacuum packaged at −30°C. The remaining 4 patties assigned for evaluation of instrumental color with a Minolta colorimeter, visual discoloration by 2 trained panelists, and final level of lipid oxidation were overwrapped with polyvinyl chloride film and allotted to a simulated retail display for 7 d under LED lights at 4°C. Fatty acid profile was analyzed on subcutaneous fat. Pearson correlation coefficients were determined using PROC CORR of SAS (SAS Institute Inc., Cary, NC), whereas relationships between meaningful variables were analyzed with simple linear regression using PROC REG of SAS. Correlations were considered weak at |r| < 0.35, moderate at 0.36 ≤ |r| < 0.67, and strong at |r| ≥ 0.68. Coefficients of determination (r²) were considered weak at r² < 0.12, moderate at 0.13 ≤ r² < 0.45, and strong at r² ≥ 0.46.

Results: Greater lipid content was strongly correlated with the decrease in a* (r = −0.70; P < 0.01), and the increase in ΔE (r = 0.68; P < 0.01), whereas lipid content was moderately correlated with the increase in visual discoloration (r = 0.53; P < 0.01). Likewise, lipid oxidation rate was moderately correlated with the decrease in a* (r = −0.50; P < 0.01), and the increase in ΔE (r = 0.52; P < 0.01); however, lipid oxidation rate was weakly correlated with the increase in visual discoloration (r = 0.26; P < 0.01). A positive moderate correlation (r = 0.36; P < 0.01) was observed between lipid content and lipid oxidation. Fatty acid composition was weakly correlated (|r| < 0.35; P < 0.01) with lipid oxidation and lipid content. Lipid content was a strong predictor for Δa* (r² = 0.49) and ΔE (r² = 0.47). Lipid oxidation could be moderately (0.13 ≤ r² < 0.45) predicted by instrumental color and lipid content and weakly (r² = 0.07) predicted by visual discoloration rate.

Conclusion: Lipid content played a more critical role in discoloration compared with lipid oxidation and fatty acid composition. Lipid oxidation could be more reliably predicted by lipid content and instrumental color compared with visual discoloration. Overall, greater lipid content leads to greater rates of lipid oxidation and discoloration.

Keywords: color stability, fatty acid profile, ground beef, lipid content, lipid oxidation

124 NATIVE BEEF COLLAGENASE MAY CONTRIBUTE TO POSTMORTEM COLLAGEN DEGRADATION AND ALTERATION OF CONNECTIVE TISSUE TEXTURE

L. A. Koulicoff^1*, C. K. Chun¹, T. G. O’Quinn¹, and M. D. Chao¹, ¹Animal Sciences and Industry, Kansas State University, Manhattan, Kansas, USA, *larissakoulicoff@ksu.edu

Objectives: Collagen is one of the main components in the connective tissue (CT) and contributes to background toughness in beef. It is known that in living animals, collagen can be degraded and remodeled by collagenase matrix metalloproteinases (MMP); however, it is unclear whether collagenase MMP can impact CT texture during postmortem aging of beef. Therefore, this study aimed to characterize native beef collagenase activity and its relationship to beef tenderness in 3 different cuts and 4 different aging periods.

Materials and Methods: Longissimus lumborum (LL), gluteus medius (GM), and gastrocnemius (GN) muscles from both sides were acquired from 10 USDA choice beef carcasses. Each muscle was fabricated into steaks and aged at 2°C ± 2°C for 4 different aging periods: 3, 21, 42, and 63 d. Warner-Bratzler shear force (WBSF), connective tissue shear force (CTSF), trained panel, collagen content, and collagenase MMP activity through collagen zymography using bovine type I collagen were performed.

Results: As expected, WBSF results indicated that LL had the lowest WBSF among all (P < 0.01), with no difference found between GM and GN (P > 0.10). Steaks increased in tenderness from 3 to 21 d of postmortem aging, but no further improvement was found beyond 21 d (P < 0.01). CTSF revealed an interaction between muscle and aging (P < 0.05). LL decreased in CTSF from 3 to 21 to 63 d of postmortem aging (P < 0.05), whereas LL samples from 42 d were not different from 21 or 63 d (P > 0.10). GN at 3 d aging had the greatest CTSF value among all but softened quickly (21 d) and remained the same beyond 21 d postmortem aging (P < 0.01). On the other hand, GM showed no difference in CTSF among the aging periods (P > 0.10). Trained panelists reported that GN and GM did not differ in CT content from each other (P > 0.10) and had greater CT amount than LL (P < 0.01). In addition, the trained panelists also noticed more CT amount at 3 d aging steaks than steaks from the rest of the aging periods (P < 0.05). GN and GM did not differ in collagen content (P > 0.10) and had greater collagen content than LL (P < 0.01). However, no aging effect was found for collagen content (P > 0.10). Two distinct sets of unknown collagenase MMP activity were detected at 72 and 92 kDa in the collagen zymography. The 72 kDa MMP had the greatest activity at 3 d aging; MMP activity decreased from 3 to 21 to 42 d (P < 0.01), and no further decrease was found beyond 42 d of postmortem aging. Seventy-two kDa MMP also had the greatest activity in GN muscle compared with the others (P < 0.01). An interaction between aging and muscle (P < 0.05) was found for the 92 kDa MMP, which showed that GN 63 d had greater 92 kDa MMP activity than GN at 3 d postmortem (P < 0.01), whereas the LL and GM did not differ within the aging periods for the 92 kDa MMP activity (P > 0.10).

Conclusion: The findings from this study provided proof that native collagenase MMP are active in postmortem beef muscles. Both CTSF and trained panels indicated CT softening during postmortem aging, but no change in collagen content was observed. Therefore, we suspect that the collagenase MMP do not work by removing collagen but by altering the collagen structure. Further studies are needed to understand the mechanism of action for the collagenase MMP in beef.

Keywords: beef, collagen, connective tissue, matrix metalloproteinases, tenderness

125 A PROPOSED ELISA METHOD TO EVALUATE ELASTIN CONTENT IN BEEF SHANK AND UNDERSTANDING ELASTIN CONTENTS’ EFFECT ON BEEF SHANK TENDERNESS

E. Verrill^1*, W. J. Wu¹, and M. D. Chao¹, ¹Animal Sciences and Industry, Kansas State University, Manhattan, Kansas, USA, *larissakoulicoff@ksu.edu

Objectives: Collagen and elastin are both major proteins of connective tissue. Collagen and its role in beef tenderness has been extensively studied, but there is no documentation on the effect of elastin on cooked beef tenderness. This is mostly due to the lack of a convenient and reliable methodology to accurately quantify elastin content in meat. Desmosine is an amino acid that is unique to elastin, and perhaps this amino acid can be used to quantify elastin content in meat. Therefore, the objective of this study was to determine whether a competitive enzyme-linked immunosorbent assay (ELISA) method for desmosine can be used to estimate the elastin content in beef and investigate elastin’s relationship to cooked beef shank tenderness.

Materials and Methods: Six different shank muscles, 3 from the foreshank (biceps brachii [BB], deep digital flexor [DDF-F], and extensor carpi radialis [ECR]) and 3 from the hindshank (flexor digitorum superficialis [FDS]; deep digital flexor [DDF-H]; and a combination of long digital extensor, medial extensor, and peroneus tertius [LMP]) were collected from 8 USDA choice beef carcasses (n = 48). The shank muscles from the right were designated as raw, and the shank muscles from the left were cooked (stewed in water for 90 min at 93°C). The samples were hydrolyzed in 6M HCl, and the elastin content was determined for the raw and cooked shanks using ELISA. Briefly, high binding microwell plates were coated with desmosine ovalbumin, incubated and blocked with a blocking buffer. The standards and samples were diluted with the blocking buffer and added to the plate, along with an antidesmosine primary antibody. After incubation, the secondary antibody was added, followed by the addition of tetramethyl benzoate to initiate a reaction between the peroxidase and the substrate. Finally, the reaction was quenched by the addition of sulfuric acid and read at 450 nm using a spectrophotometer. A 4-parameter logistic regression equation was generated using commercially available desmosine standards, and we were able to achieve a coefficient of determination (R²) of 0.99. In addition, beef backstrap samples were used as a positive control, and the elastin content of beef backstrap using the proposed competitive ELISA method was ∼5.8 mg/g of muscle tissue, which is comparable to the value provided by Bendall (1967).

Results: Of the 6 muscles evaluated, BB, DDF-F, ECR, FDS, DDF-H, and LMP had an average elastin content of 2.29, 1.03, 0.68, 0.45, 1.13, and 0.85 mg/g of muscle tissue, respectively. The BB had the greatest level of elastin content compared with the other shank cuts (P < 0.01), and cooked beef shanks had greater elastin content than raw beef shanks (P < 0.05). However, correlation analysis indicated that there is no relationship between elastin content and cooked beef shank shear force (P > 0.10).

Conclusion: This study demonstrated that elastin content differed among locomotive beef muscles, possibly owing to differences in functional needs. In addition, it further confirmed that elastin is heat and water insoluble. Finally, elastin’s lack of correlation to cooked beef shank tenderness is possibly due to elastin content being relatively insignificant compared with collagen in connective tissue of muscle. However, this proposed competitive ELISA methodology may be suitable to accurately determine elastin content in beef.

Keywords: beef shanks, connective tissue, elastin, ELISA, tenderness

126 EFFECT OF ROTENONE ON GROUND BEEF COLOR

M. Lawson¹, M. L. Denzer¹, F. Kiyimba^1*, G. G. Mafi¹, and R. Ramanathan¹, ¹Department of Animal and Food Sciences, Oklahoma State University, Stillwater, Oklahoma, USA, *mdenzer@ostatemail.okstate.edu

Objectives: Oxygen consumption (OC) is an inherent muscle property that influences fresh beef color. Furthermore, greater OC results in less bloom and darker meat color, whereas lower OC produces a bright-red color that is more desirable to consumers for purchase and consumption. In postmortem muscles, mitochondria and oxygen-consuming enzymes are primarily involved in OC and are important in characterizing beef color changes. Although previous studies reported the role of mitochondria in beef color, limited studies have validated mitochondria’s role in color. Here, we discuss the effect of complex I mitochondrial inhibitor, rotenone, on fresh meat color. Therefore, the objective of this study was to validate the role of mitochondria on meat color.

Materials and Methods: Chuck steaks were purchased from a local retail store and were coarse ground. Treatments included a control without rotenone, 0.1% rotenone, and 0.2% rotenone. All treatments were vacuum packaged and stored for 24 h to react. The coarse ground beef was then finely ground, hand-formed to 115 g patties, and packaged in polyvinyl chloride film. The patties were kept in a retail display case for 3 d. Surface color, OC, metmyoglobin reducing activity (MRA), lipid oxidation, pH, and NADH content were determined during 3 d of display. The experiments were replicated 3 times, and the data were analyzed using the Mixed Proc of SAS (SAS Institute Inc., Cary, NC).

Results: There was no effect (P > 0.05) of rotenone addition on pH levels. The addition of rotenone improved (P < 0.05) redness of the patties compared with rotenone. The addition of rotenone decreased (P < 0.05) OC, likely because of the inhibition of complex I activity and utilization of NADH. Additionally, NADH levels were lower (P < 0.05) in rotenone-treated samples than non–rotenone-treated samples. Lipid oxidation was lower in rotenone-treated samples in comparison with the control. Interestingly MRA was greater (P < 0.05) in rotenone-treated samples than in control patties. MRA can occur by 3 different pathways, and in the current research, only complex I was blocked with rotenone.

Conclusion: In conclusion, decreased lipid oxidation and other MRA pathways may have increased MRA and redness. Inhibition of all complexes will provide additional insights into the role of mitochondria in beef color.

Keywords: beef color, mitochondrial inhibitor, oxygen consumption, rotenone

127 DIFFERENCES IN EARLY POSTMORTEM PH AND TENDERNESS VALUES OF BEEF LONGISSIMUS THORACIS MUSCLE ARE INFLUENCED BY METABOLISM AND APOPTOTIC PATHWAYS

M. D. Schulte^1*, E. M. Steadham¹, S. M. Lonergan¹, S. L. Hansen¹, and E. Huff-Lonergan¹, ¹Department of Animal Science, Iowa State University, Ames, Iowa, USA, *schulte1@iastate.edu

Objectives: Understanding how early postmortem (PM) pH and energy metabolism drive differences in beef tenderness is necessary to establish methods to improve and predict beef tenderness. The hypothesis tested was that beef longissimus thoracis (LT) muscle metabolome and proteome differences at 1 h PM dictate early PM pH linked to variations in early PM beef tenderness.

Materials and Methods: Twenty beef steers were slaughtered. Temperature and pH (1, 3, 6, and 24 h) were measured on the LT. Beef LT rib sections were sorted by 6 h pH values to low (LpH; n = 9; <5.55 pH; pH range: 5.37–5.54) and high (HpH; n = 8; >5.84 pH; pH range: 5.85–5.98) pH classifications. Warner-Bratzler shear force (WBSF) was determined on steaks (2.54 cm; 1, 3, 7, or 14 d) cooked to 68°C. LT muscle samples (1 h, 1, 3, 7, and 14 d PM) were frozen. Protein degradation was determined by Western blotting. Sarcoplasmic protein extracts (1 h PM) were used to conduct 2D-DIGE. Nontargeted metabolomic analyses were conducted on muscle extract (1 h PM) using gas chromatography–mass spectrometry. Temperature, pH, WBSF, and protein degradation data were analyzed using the Mixed procedure of SAS version 9.4 (SAS Institute Inc., Cary, NC) (fixed effect = classification; significance of P ≤ 0.05, trends of 0.05 < P ≤ 0.10). MetaboAnalyst 5.0 (Xia Lab, McGill, CA) was used to analyze metabolites; significance was set at a fold change (FC) of ≥1.25; P ≤ 0.10. Melanie 9 (Cytiva, Marlborough, MA) was used to conduct paired t tests to determine protein abundance differences (FC ≥ 1.10; P ≤ 0.10).

Results: LpH had a lower pH at 1 (P = 0.01), 3 (P < 0.01), and 6 (P < 0.01) h PM and tended to have a lower 24 h pH (P = 0.07), and a greater temperature at 1 (P = 0.08) and 24 (P = 0.07) h PM. WBSF was lower at 1 d PM (P = 0.01) and greater at 7 d PM (P = 0.05) in LpH. Classification did not affect WBSF at 14 d PM (P = 0.23). At 1 d PM, LpH had greater desmin degradation (P = 0.01), a trend for greater troponin-T degradation (P = 0.08), and greater calpain-1 autolysis (P = 0.01). Proteome analysis at 1 h PM detected a greater abundance of proteins involved in energy metabolism and lesser abundance of proteins involved in apoptosis in LpH (Table 1). Metabolite analysis at 1 h PM revealed greater abundance of succinate (FC = 2.58, P < 0.01), lactate (FC = 1.32, P = 0.01), glucose (FC = 3.43, P = 0.05), and glucose-6-phosphate (FC = 1.37, P = 0.07), as well as revealed less pyruvate (FC= 0.51, P = 0.09) in LpH.

Conclusion: LpH had lower WBS values at 1 d PM because of greater protein degradation. Differences in protein degradation could be explained by calpain-1 autolysis. Energy metabolism proteins and metabolites in glycolytic pathways are linked to PM pH values and could be drivers of LpH phenotype. Similar 14 d WBS values were achieved between pH classifications; however, LpH achieved this sooner through earlier proteolytic mechanisms.

Keywords: beef, metabolome, pH decline, proteome, tenderness

128 SURFACE COLOR VARIATION BETWEEN ANGUS AND BRAHMAN LONGISSIMUS LUMBORUM MUSCLE

E. Chmielewski^1*, B. Hawryluk¹, C. Gingerich¹, M. McKinney¹, P. Ramos¹, and T. Scheffler¹, ¹Department of Animal Sciences, University of Florida, Gainesville, Florida, USA, *tscheffler@ufl.edu

Objectives: Meat color is a major factor that affects consumer purchasing decisions. Myoglobin (mb), a sarcoplasmic heme protein, is the primary pigment responsible for the color of postmortem muscle. Both mitochondria content and activity may influence color development. Previously, we have shown that Brahman and Angus exhibit variation in postmortem metabolism and mitochondrial function. Thus, the objective of this study was to evaluate color, mb, and mitochondria content in longissimus lumborum (LL) from Brahman and Angus.

Materials and Methods: Angus and Brahman steers (n = 14 per breed), reared in the same conditions, were harvested at the University of Florida meat lab. Samples were collected from the LL at 1 and 24 h postmortem, immediately frozen in liquid nitrogen, and stored at −80°C. At 48 h postmortem, carcasses were ribbed, and steaks were removed. The L*, a*, and b* were taken using a HunterLab spectrophotometer and used to calculate hue and chroma. An additional LL sample was collected at 48 h and stored at −80°C. The pH of the LL at 48 h was determined using muscle homogenate. mb concentration (mg/g LL; 1, 24, and 48 h) was assessed by absorbance at 525 nm using spectrophotometry. Protein expression of mb, the mitochondrial marker citrate synthase (CS), and complex IV subunit (cytochrome c oxidase subunit IV [COX IV]) were evaluated (1 and 24 h) using Western blotting. Data were analyzed using an unpaired t test in SAS-JMP.

Results: Breed influenced L* (P < 0.0001) and a* (P = 0.01) as well as b* (P < 0.05), with Angus exhibiting higher values. Chroma demonstrated more (P < 0.05) color saturation in Angus compared with Brahman. The pH was not different between breeds (P = 0.89). The mb concentration was numerically higher in Angus at all times; mb tended to be higher at 1 h (P = 0.06) and 48 h (P = 0.09) but was not different at 24 h (P = 0.40). Similarly, protein expression of mb differed between breeds at 1 h (P = 0.03) but not 24 h (P = 0.44). Breed did not influence protein expression of CS at 1 h (P = 0.43) or 24 h (P = 0.34). However, COX IV tended to be higher in Brahman at 1 h (P = 0.09) and 24 h (P = 0.05).

Conclusion: Angus displayed greater redness, yellowness, lightness, and color saturation in the LL compared with Brahman. As CS was not different, the mitochondrial content of postmortem LL is likely not related to the increase in surface color values of Angus. The greater mb concentration in Angus evidences greater capacity for oxygen storage, whereas the lower COX IV may contribute to decreased mitochondrial activity. Together, this suggests that altered balance between oxygen storage capacity and mitochondrial oxygen consumption contributed to color differences between breeds.

Keywords: color, mitochondria, myoglobin

129 NOVEL GENES AND MICRORNA AS BIOMARKERS FOR MEAT TENDERNESS

F. Giotto^1*, M. Li², T. Zhou², B. Ferguson³, and A. S. De Mello¹, ¹Agriculture, Veterinary, and Rangeland Sciences, ²Phisiology and Cell Biology, and ³Nutrition, University of Nevada, Reno, Nevada, USA, *ademello@unr.edu

Objectives: Molecular signatures of beef tenderness indicate that protein biomarkers associated to tenderization/proteolysis pathways may serve as predictors for tenderness. Genes such as CAPN2, CAPN15, CAST, CASP3, and PSMC4 and proteins translated from other genes that modulate muscle growth and development have been identified as potential biomarkers for tenderness. In our previous studies, we observed that the expression of microRNA (miR) may increase postmortem. Therefore, expression of certain genes in live animals or at day 0 postmortem may not properly predict tenderness after 14 d of aging. We evaluated the correlation between the expression of 8,209 genes with Warner-Bratzler shear force (WBSF) values of beef aged 0 and 14 d, and the correlation of 315 miR with WBSF values of beef aged 0, 14, and 28 d.

Materials and Methods: Strip loin steaks were aged for 0, 14, and 28 d, and 2-g aliquots from steaks were obtained and frozen. The remainder of the steaks were cooked and WBSF analysis performed. RNA was isolated from the 2-g aliquots via Triazol and quantified and integrity assessed via BioAnalyzer 2100 (Agilent, Santa Clara, CA). Barcoded miRNA-Seq libraries were prepared using the NEXTflex Small RNA Sequencing v3 kit (Bioo Scientific, Austin, TX) with randomized adapters according to the recommendations of the manufacturer. The fragment size distribution of the libraries was verified via micro-capillary gel electrophoresis on a Bioanalyzer 2100 (Agilent, Santa Clara, CA). The libraries were quantified by fluorometry on a Qubit instrument (LifeTechnologies, Carlsbad, CA) and pooled in equimolar ratios. Twelve libraries were sequenced on one lane of a HiSeq 4000 sequencer (Illumina, San Diego, CA) with single-end 100 bp reads. The large and small RNA sequencing data were summarized by the Salmon and SPORTS computational pipelines, respectively. Transcripts per million (TPM) and reads per million (RPM) were used as the unit for mRNA and miRNA expression, respectively. The differentially expressed genes and miRNA were identified by the edgeR tool. Level of significance was P < 0.05.

Results: As expected, tenderization/proteolysis pathway genes CAPN2, CASP3, and PSMC4 significantly decreased for aged beef (14 d; P < 0.05). Expression of CAPN15 and CAST was statistically similar when comparing non-aged versus aged beef (0 vs. 14 d). None of those genes were directly correlated to WBSF.

Our data showed 42 other genes that directly correlated to WBSF values of beef aged 0 and 14 d, but only ACTN4, ERF, and MYL12B modulate enzymes and proteins that have been associated to meat tenderness or cell death. The remaining 39 genes were associated to other metabolic pathways. The expression of 19 miR was significantly different across 0, 14, and 28 d. Correlations between miR and WBSF values were observed for 7. Bta-miR-1434, bta-miR-2404-1, bta-miR-2404-2, bta-miR-2427, bta-miR-2478, and bta-miR-2484 were positively correlated to higher WBSF values, and bta-miR-499 was negatively correlated to higher WBSF.

Conclusion: Genes associated with metabolic pathways that are not directly related to meat tenderization and proteolysis may better predict meat tenderness when compared with genes such as CAPN2, CAPN15, CAST, and CASP3. The increase or decrease in expression of miR postmortem indicates that miR may also be used as biomarkers for tenderization from day 0 to 28.

Keywords: beef, biomarker, microRNA, tenderness

130 EFFECTS OF OXYGEN ON NON-ENZYMATIC METMYOGLOBIN REDUCTION IN VITRO

M. Scott^1*, M. L. Denzer¹, G. G. Mafi¹, M. Pfeiffer¹, and R. Ramanathan¹, ¹Department of Animal and Food Sciences, Oklahoma State University, Stillwater, Oklahoma, USA, *mdenzer@ostatemail.okstate.edu

Objectives: Predominant oxymyoglobin imparts consumer-preferred bright cherry-red meat color, but discoloration on meat negatively impacts purchasing decisions. Oxymyoglobin oxidation results in the formation of brown-colored metmyoglobin. Oxidation can occur more readily in common retail settings such as exposure to light and oxygen (O₂); however, meat has an inherent ability to reduce the brown pigment and form a cherry-red color through metmyoglobin reducing systems. Non-enzymatic metmyoglobin reduction (NMR) indicates metmyoglobin occurs in the absence of enzymes or mitochondria. Research indicated that inherently present electron donors and carriers could contribute to NMR activity. Previous research from our laboratory has demonstrated that the presence of light increased NMR activity in comparison with dark storage. However, limited knowledge is available on the impact of oxygen levels on non-enzymatic reduction. The objective of this study was to evaluate the effect of oxygen levels on NMRA in vitro.

Materials and Methods: Solutions of ascorbate and NADH were used as the electron donors, and cytochrome c (cyt-c) and methylene blue (MB) served as electron carriers. Equine metmyoglobin solution at pH 5.6 was combined with different electron donors and carriers in a 96-well plate. Six treatments included in the study were as follows: 1) NADH, 2) NADH + MB, 3) NADH + MB + ethylenediaminetetraacetic acid (EDTA), 4) NADH + cyt-c + EDTA, 5) ascorbate + MB + EDTA, and 6) ascorbate + cyt-c + EDTA. Each treatment was added into a clear-bottom 96-well plate with each well containing a total of 300 microliters. A high-oxygen gas blend of 80% oxygen and 20% carbon dioxide or a pure 99.9% nitrogen gas was bubbled in phosphate buffers and myoglobin solutions to create 2 oxygen levels (low-oxygen and high-oxygen). An Ocean Optics Neofox oxygen sensor was utilized to measure oxygen content in solutions. Metmyoglobin reduction was monitored every 5 min for 25 min using a spectrophotometer set to 582 nm. The experiment was replicated 3 times with 6 technical replicates per treatment. The data were analyzed using the Mixed Procedure of SAS (SAS Institute Inc., Cary, NC) with a completely randomized design.

Results: The oxygen levels in reaction mixtures were 160% and 4%, respectively, in high- and low-oxygen treatments. The percentage levels were relative to the amount of oxygen remaining in the solution following flushing. There was a significant treatment by oxygen effect on the metmyoglobin reduction. An increase in NMR (P < 0.0001) was observed for both combinations of NADH + MB + EDTA and MB + NADH in a high-oxygen atmosphere in comparison with a low-oxygen atmosphere. The metmyoglobin reduction was limited (P > 0.05) in the presence of NADH alone and within the combination of NADH + cyt-c + EDTA for both oxygen atmospheres. Interestingly, when cyt-c was used as an electron carrier, there was no (P > 0.05) oxygen-level–specific effect.

Conclusion: The current research indicates that level of oxygen has substrate-specific effects on NMR. In conclusion, characterizing the factors affecting metmyoglobin reducing activity helps to develop strategies to improve meat color.

Keywords: meat color, metmyoglobin reducing ability, myoglobin

131 USING PLIMB-GENERATED HYDROXYL RADICALS TO DETERMINE SOLVENT ACCESS TO THE HEME POCKET OF HNE ADDUCTED BOVINE MYOGLOBIN

J. Whalin¹, S. P. Suman², Y. Wang², J. L. Shohet³, and M. P. Richards^1*, ¹Animal and Dairy Science, University of Wisconsin–Madison, Madison, Wisconsin, USA; ²Animal and Food Sciences, University of Kentucky, Lexington, Kentucky, USA; ³Electrical and Computer Engineering, University of Wisconsin–Madison, Madison, Wisconsin, USA, *whalin@wisc.edu

Objectives: The mechanism of aldehyde-induced oxidation of myoglobin resulting in loss of red color requires further characterization. This work utilized Plasma Induced Modification of Biomolecules (PLIMB) to generate hydroxyl radicals and footprint the heme pocket of both 4-hydroxy-2-nonenal (HNE) adducted and non-HNE adducted bovine myoglobin. One hypothesized mechanism of myoglobin oxidation is based on solvent access to the distal heme pocket that can be examined by PLIMB.

Materials and Methods: PLIMB: A 10 kilohertz signal of 10 volts was generated and amplified to 10 kV, which was then discharged from a steel needle 1 mm above protein in buffer. Fifty μL of myoglobin (20 μM) in sodium phosphate buffer (50 mM, pH 6.5) was used per exposure. Experimental replicates of both the protein type (2) and time of exposure (4) were used for a combined total of 16 samples. Orbitrap MS/MS: After a trypsin/LysC digest, samples were cleaned with a C18 OMIX tip. Samples were injected into a Pepmap C18, 3 μM, 100A, 25 μM ID, 15 cm reversed phase column and ionized with an EASY-Spray Ion Source. Samples were analyzed with an Orbitrap Elite in data-dependent tandem mass spectrometry (MS/MS) mode and with Protein Metrics Byos software. Plasma-induced modifications of side chains included (I) mono-oxidation as +15.99 Da, (II) di-oxidation as +31.99 Da, (III) His to Asp as −22.032 Da, (IV) His to Asn as −23.016 Da, (V) Lys to Arg as +28.006 Da, (VI) Carbamidomethyl as +57.021 Da, (VII) Gln to pyro-Gln as −17.026 Da, and (VIII) Glu to pyro-Glu as −18.010 Da.

Results: There are 17 amino acids within 4 angstroms of the heme iron-protoporphyrin ring that collectively form the distal and proximal pockets, and all 17 residues were examined for oxidative modification from PLIMB. Only 5 residues (K42, Y103, F138, H64, and I107) were found to be modified, composed of 3 proximal and 2 distal pocket residues. With PLIMB exposure of 0, 0.25, 0.25, and 0.75 s, only F138 was found to have modification above 1% and showed clear dose dependency. Validated modifications of F138 included mono-oxidation (+16 Da) and di-oxidation (+32 Da). Statistically, analysis of variance (n = 16) was used to determine both dose dependency of PLIMB exposure and treatment effect (HNE adducted vs. non-HNE adducted) of the F138 residue. Interestingly, solvent access was trending higher (P < 0.09) in non-adducted myoglobin compared with HNE-adducted myoglobin for the F138 residue. These data suggest that while HNE adducted myoglobin undergoes more rapid oxidation, the mechanism of that oxidation may be outer sphere whereby the distal histidine is not overly protonated by solvent entering the heme pocket. Instead, the heme iron is oxidized by a non-associated oxygen.

Conclusion: The study demonstrates the potential for the use of PLIMB in conjunction with MS/MS to study solvent access to myoglobin. F138 appears to be more modified in non-HNE adducted myoglobin, which suggests that the outer sphere mechanism may be the dominant mechanism of heme oxidation that explains the greater observed oxidation in HNE adducted myoglobin. If the inner-sphere mechanism were responsible for the different rates of oxidation, then the distal histidine (or other residues that form the heme pocket) would be expected to be more modified in the HNE adducted myoglobin, but that effect was not observed.

Keywords: 4-hydroxy-2-nonenal, heme, myoglobin, oxidation, protein footprinting

132 FUNCTIONAL CHARACTERISTICS OF PEROXIREDOXIN-2 UNDER IN VITRO CONDITIONS MIMICKING EARLY POSTMORTEM SKELETAL MUSCLE

L. G. Johnson^1*, E. M. Steadham¹, E. Huff-Lonergan¹, and S. M. Lonergan¹, ¹Animal Science, Iowa State University, Ames, Iowa, USA, *logan01@iastate.edu

Objectives: Protein oxidation adversely affects meat tenderness development. Peroxiredoxins are a family of thiol antioxidant proteins. The form and abundance of peroxiredoxin-2 (Prdx2) vary in prerigor and postrigor porcine skeletal muscle and are associated with meat tenderness and animal phenotype. The cellular events and environments that generate variation in Prdx2 are not defined. Moreover, the impact of Prdx2 on the development of fresh meat quality is not clear. Therefore, the objective was to conduct controlled in vitro experiments with partially purified Prdx2 to enhance the understanding of Prdx2 in postmortem skeletal muscle. It was hypothesized that Prdx2 is rapidly oxidized by hydrogen peroxide (H₂O₂), and oxidized Prdx2 is less susceptible to degradation by calpain-1.

Materials and Methods: Peroxiredoxin-2 preparations from the diaphragm, psoas major, and longissimus lumborum were used. Partially purified Prdx2 (35%–50% pure) from all muscles was dialyzed against 40 mM Tris-HCl (pH 7.0) and 1 mM EDTA (TE) or TE 2-(N-morpholino) ethanesulfonic acid (pH 6.0) for 2 h at 4°C. Prdx2 (2 μg) was incubated with either 100 or 500 μM H₂O₂ for 2, 15, or 60 min on ice. Prdx2 was incubated with purified porcine calpain-1 in the presence and absence of 2-mercaptoethanol (2ME). Prdx2 (2 μg) was adjusted to 1 mM CaCl₂ and incubated with 0.025 U purified calpain-1 for 15, 60, 180, or 1,440 min on ice in the presence of 0.5% 2ME. To remove residual 2ME, Prdx2 and calpain-1 were dialyzed against TE (pH 7.4). Prdx2 (2 μg) was reacted with 500 μM H₂O₂ for 1 h on ice, after which CaCl₂ was adjusted to 1 mM. Purified calpain-1 (0.05 U) was added to each tube and incubated for 15, 60, 180, or 1,440 min on ice. After each in vitro incubation, denaturing buffer was added to each tube. Prdx2 was detected with immunoblot techniques using monoclonal rabbit anti-peroxiredoxin-2 antibody (ab109367; ABCam, Cambridge, UK). All in vitro incubations were replicated (n = 3) per muscle on separate days. Data were analyzed using the MIXED procedure of SAS version 9.4 (SAS Institute Inc., Cary, NC). Incubation time was used as a fixed effect, and gel was used as a random effect.

Results: At pH 7.0, the Prdx2 monomer and dimer decreased after incubation with 100 μM H₂O₂ between 2 and 60 min (P < 0.05). The Prdx2 dimer increased at pH 7.0 after incubation with 500 μM H₂O₂ between 2 and 60 min (P < 0.05). At pH 6.0, the Prdx2 monomer decreased, whereas the dimer increased after incubation with 100 and 500 μM H₂O₂ between 2 and 60 min (P < 0.05). The intact Prdx2 monomer decreased (P < 0.05) after 180- and 1,440-min incubation with calpain-1 in the presence of 2ME. In the absence of 2ME, the Prdx2 dimer decreased (P < 0.05) after 180- and 1,440-min incubation with calpain-1 in the diaphragm, decreased after 1,440 min in the psoas major, but did not change in the longissimus lumborum.

Conclusion: Peroxiredoxin-2 from porcine skeletal muscle reacts with H₂O₂ at pH 6.0 and 7.0. Calpain-1 was able to degrade Prdx2 monomer and dimer; however, the Prdx2 degradation product that was generated in vitro has not been observed previously and may be limited in postmortem meat. The variation in Prdx2 form and abundance from previous meat tenderness studies may be due to Prdx2 solubility or oxidation state differences, such as being present in the hyperoxidized form. Prdx2 may influence the extent of protein oxidation in early postmortem skeletal muscle and promote meat tenderness development.

Keywords: calpain-1, hydrogen peroxide, oxidation, peroxiredoxin-2, porcine

133 A PROPOSED REEVALUATION OF THE IMPACT OF FEEDING DISTILLERS GRAINS PLUS SOLUBLES ON MEAT QUALITY USING A GOAT MEAT MODEL

F. B. McDonald¹, L. Rimmer^1*, C. K. Y. Chun¹, C. K. Jones¹, A. R. Crane¹, and M. D. Chao¹, ¹Animal Sciences and Industry, Kansas State University, Manhattan, Kansas, USA, *larissakoulicoff@ksu.edu

Objectives: Effect of feeding distillers grains on ruminant meat quality has been well researched in the past decade. However, some studies have suggested that feeding distillers grains can have negative impacts on meat quality, whereas some have demonstrated no negative impact, potentially even improved meat shelf life in some cases. Corn is inherently rich in antioxidants; as the starch is converted to ethanol, the rest of the grain constituents are concentrated in the distillers grains, including the antioxidants. Therefore, the idea is that feeding distillers grains to livestock will ultimately increase the antioxidant capacity in meat, thus counterbalancing the negative impact from the expected fatty acid alteration in meat. The objective of this study was to evaluate the effect of feeding distillers grains on meat antioxidant capacity and overall quality using a goat model.

Materials and Methods: Thirty goat kids (21.7 ± 0.8 kg) were fed either a soybean meal-based diet containing 33% dried distillers grains plus solubles (DDGS; n = 15) or 0% DDGS (n = 15) for 31 d. There were 6 replications (pens) for each treatment. The goats were harvested at the end of the feeding period, and the loins were collected from all 30 goat carcasses at 1 d postmortem. Loins were fabricated into four 2.54 cm chops and overwrapped for retail display. Goat chops were subjectively evaluated for discoloration and objectively measured using a colorimeter for L*, a*, and b* values on days 0, 4, 7, and 10 under retail display conditions. Samples were collected on those days and analyzed for lipid oxidation, fatty acid profile, and hydrophilic and lipophilic antioxidant concentration via oxygen radical absorbance capacity assay.

Results: Overall, visual evaluation of discoloration and meat color characteristics measured by L*, a*, and b* values confirmed that feeding DDGS to goats had no effect on goat chop discoloration (P > 0.10). However, all chops demonstrated a display effect, which they increased in visual discoloration and decreased in a* values (P < 0.01) over the entirety of the 10-d period of retail display, regardless of the dietary treatment. In addition, lipid oxidation followed the same trend as discoloration, in which the lipid oxidation value was not affected by diet but increased as the display days increased (P < 0.01). As expected, feeding 33% DDGS to goats decreased relative percentage of multiple monounsaturated fatty acids, primarily on fatty acids C16:1, C17:1, and C18:1 and total multiple monounsaturated fatty acid content (P < 0.05). At the same time, dietary intake of 33% DDGS increased relative percentage of multiple polyunsaturated fatty acids, primarily on fatty acids C18:2, C20:5 and C22:5, and total PUFA (P < 0.05). The oxygen radical absorbance capacity assay displayed no treatment difference in the hydrophilic antioxidant activity (P > 0.10), but chops from the 33% DDGS dietary treatment had greater lipophilic antioxidant activity compared with the 0% DDGS chops (P < 0.05).

Conclusion: Results from this study illustrated that feeding DDGS to goats will alter fatty acid composition in goat meat, but the supposed negative consequence from increased polyunsaturated fatty acid is likely counterbalanced by the increased antioxidant capacity in the lipid component of meat, resulting in no difference in meat shelf life. Ultimately, this study explained the cause of the variability in meat shelf life from ruminants supplemented with various forms of distillers grains.

Keywords: discoloration, distillers grains, goat meat, lipid oxidation, shelf life

134 EFFECTS OF SUCROSE AND BEEF SUPPLEMENTATION DURING MID TO LATE GESTATION ON FETAL MUSCLE GROWTH AND DEVELOPMENT USING A SOW BIOMEDICAL MODEL

N. T. Acosta-Castellanos^1*, M. A. Nelson², K. A. Vonnahme³, and E. P. Berg¹, ¹Animal Sciences, North Dakota State University, Fargo, North Dakota, USA; ²Division of Extension, University of Wisconsin–Madison, Madison, Wisconsin, USA; ³Outcomes Research, Zoetis, Fargo, North Dakota, USA, *natalie.acosta@ndsu.edu

Objectives: Myogenesis in pigs is a biphasic process where the primary generation of fibers (from 35 to 55 gestation day) are surrounded by secondary fibers (from 55 to 95 gestation day) creating a rosette shape, and finally an external ring of third generation fibers (late fetal to early postnatal period). Primary fiber number is believed to be a fixed genetic effect, whereas secondary fibers are influenced by prenatal events such as maternal diet. The aim of this study was to compare the effects of beef or sugar supplemented to a standard sow maternal diet on fetal muscle fiber development.

Materials and Methods: Twenty-one pregnant sows (Landrace × Yorkshire, starting body weight = 222 ± 35 kg) were randomly assigned to one of 4 isocaloric supplement treatments: control (CON), 126 g corn-soybean meal-based diet (CSM), 110 g cooked ground beef diet (BEEF), 85.5 g sucrose diet (SUG), or the combination of 54.8 g cooked ground beef and 42.7 g sucrose (BS). Dietary supplements were added 3 times per day to the CSM from day 40 to 110 (±0.58) of gestation. Sows were euthanized on day 111 of gestation; longissimus dorsi (LD) and semimembranosus (SM) samples were collected from 1 median-weight male and female fetus of each sow. Samples were then immunofluorescent stained to target the slow twitch (ST) and fast twitch (FT) muscle fiber types and analyzed through fluorescent microscopy to obtain the total amount of myofibers and the proportion of ST and FT fibers. Data were analyzed using the MIXED procedure of SAS (SAS Institute Inc., Cary, NC) with sow diet, fetal muscle, and fetal gender as fixed effects and replicates as a random effect with individual sow as the experimental unit. Differences were considered statistically significant at P < 0.05.

Percentage of slow and fast twitch myofibers in longissimus dorsi and semimembranosus of swine fetal muscles at 111 d of gestation.

Results: Muscle type (LD vs. SM) differed for total amount (P < 0.0001) and myofiber percentage (P < 0.0001). LD showed the largest percentage of ST fibers (SUG > BS but did not differ from CON and BEEF) and greatest total number of myofibers (CON had the highest, 5,562/1 mm²); in contrast, SM showed the largest percentage of FT fibers (BEEF = 95.8%) and the smallest value of total amount (SUG = 3,372/1 mm²). It was found that female LD and SM had a numerically greater percentage of ST fibers and smaller myofiber number than male but did not significantly differ.

Conclusion: These results suggest that this amount of beef or sucrose supplementation to a standard sow maternal diet had minimal effects on fetal muscle fiber type.

Keywords: beef, diet, myofiber, sugar, swine model

135 EFFECTS OF WET AGING ON DIFFERENTIAL PROTEIN ABUNDANCE IN DARK-CUTTING AND NORMAL-PH BEEF LONGISSIMUS LUMBORUM MUSCLES

F. Kiyimba^1*, S. D. Hartson², J. Rogers², G. G. Mafi¹, and R. Ramanathan¹, ¹Animal and Food Sciences and ²Biochemistry and Molecular Biology, Oklahoma State University, Stillwater, Oklahoma, USA, *frank.kiyimba@okstate.edu

Objectives: Dark-cutting beef is a meat quality defect associated with a very dark-meat surface color when the cut surface is exposed to oxygen. As a result, dark-cutting beef is discounted at retail due to its appearance. The greater than normal muscle pH can be associated with the dark-cutting condition. However, the effects of high pH meat on regulatory mechanisms mediating protease activity or in destabilizing methyl-transferases of protein complexes during the aging process in dark-cutting compared with normal-pH beef is still unknown. The objective of the current research was to determine the differential protein expression levels with aging in dark-cutting and normal-pH beef longissimus muscles.

Materials and Methods: Longissimus lumborum muscles from 12 different animals (6 dark-cutters and 6 USDA Choice strip loins) were collected within 48 h postmortem. Loins were sectioned into equal sections and randomly assigned to 7 and 14 d of aging, respectively. Following aging, steaks were cut, placed on foam trays, wrapped with polyvinyl packaging film, and allowed to bloom for 1 h. Steaks from Choice and dark-cutting loins were utilized to measure pH, surface color, and proteomic analysis. L*, a*, b*, and chroma were recorded using a HunterLab MiniScan spectrophotometer. Muscle samples were also subjected to quantitative proteomics analysis using LC-MS/MS–based proteomics. Surface color data were analyzed using the Mixed Procedure of SAS. Proteomics data were analyzed using several bioinformatics approaches, and the aging-related changes in protein expression profiles were considered significant at a false discovery rate (FDR) < 0.05.

Results: Aging time increased (P < 0.05) a*, L*, and chroma values for dark-cutting beef, whereas only a numerical increase (P > 0.05) was observed in USDA Choice steaks. Mass spectrometry analysis identified 1,000 proteins, of which 283 showed significant differential abundance of aging-related changes (FDR < 0.05) between dark-cutting and USDA Choice beef. Quantitative analysis revealed that aging mainly affected protein abundance in high pH meat (dark-cutting) compared with Choice beef. Of the 282 differentially expressed proteins, 95 were upregulated, and 25 were downregulated on day 7 postmortem in dark-cutting beef. In contrast, 25 proteins were upregulated and 49 were downregulated on day 14 (fold change > 1.5, FDR < 0.05) in dark-cutting beef. The majority of the upregulated proteins in dark-cutting beef on day 7 were involved in redox homeostasis, chaperon and protease mediated stress responses. Conversely, cytosolic proteins involved with energy metabolism processes such as glycolysis, glycogen degradation, glycerol-phosphate shuttle, stress, and heat shock proteins were downregulated by day 14 postmortem in dark-cutting beef.

Conclusion: Overall, our finding reveals different aging-related proteolytic degradation mechanisms in dark-cutting compared with normal-pH beef. Understanding the biochemical basis of dark-cutting beef has implications for increasing economic benefits associated with effective and targeted enhancement interventions for improving the color of dark-cutting beef.

Keywords: aging, dark-cutting beef, mass spectrometry, meat color, proteomics

136 DIFFERENCES IN THE METABOLOME OF BEEF LONGISSIMUS THORACIS MUSCLE FROM STEERS SUPPLEMENTED SUPRANUTRITIONAL ZINC AND RACTOPAMINE HYDROCHLORIDE COULD EXPLAIN EARLY POSTMORTEM PH DECLINE AND TENDERNESS VARIATIONS

M. D. Schulte^1*, E. M. Steadham¹, S. M. Lonergan¹, S. L. Hansen¹, and E. Huff-Lonergan¹, ¹Department of Animal Science, Iowa State University, Ames, Iowa, USA, *schulte1@iastate.edu

Objectives: Ractopamine hydrochloride (RAC) and supranutritional zinc (Zn) influence pH values and tenderness development. The hypothesis was that differences in the early postmortem (PM) metabolome and proteome of longissimus thoracis (LT) muscle from beef cattle supplemented supranutritional Zn and RAC influence pH values and early PM tenderness.

Materials and Methods: Angus crossbred steers were assigned to dry rolled corn diets based on growth potential and initial body weight: non-Zn supplemented control (CON-NO; 36 mg Zn/kg dry matter; n = 5), supranutritional Zn supplementation (SUPZN-NO; CON diet + 60 ppm Zn from ZnSO₄+ 60 ppm Zn from Zn amino acid complex; n = 5), CON + RAC supplementation (CON-RAC; 300 mg RAC-steer⁻¹ d⁻¹; n = 5), and SUPZN + RAC supplementation (SUPZN-RAC; n = 5). Zn treatments were fed for the entire 89 d trial. RAC was fed for the final 28 d for RAC treatments. On 5 different harvest dates, 1 steer per treatment was harvested (n = 4/d). LT pH values were taken (1, 3, 6, and 24 h PM). LT muscle samples were taken at 1 h and 1 d PM and frozen. Warner-Bratzler shear force (WBSF) values were determined on cooked (68°C) steaks (2.54 cm; 1, 3, 7, or 14 d PM). Western blot analysis was used to determine protein degradation (1 d PM). Muscle extracts (1 d) were used for nontargeted metabolomics using gas chromatography–mass spectrometry. Sarcoplasmic protein extracts (1 d PM) were used for liquid chromatography–tandem mass spectrometry with tandem mass tagging. WBSF, pH, and protein degradation data were analyzed as a 2 × 2 factorial using the mixed procedure of SAS version 9.4 (fixed effects = Zn, RAC, and the interaction; block = harvest date). Significance was P ≤ 0.05, and trends were 0.05 < P ≤ 0.10. Metabolomic data were analyzed using MetaboAnalyst 5.0. Significance was a fold change of ≥1.25; P < 0.10. Proteomic data were analyzed using t tests. Significance was set at a P < 0.10.

Results: Interactions were not significant; main effects will be presented. At 6 h PM, Zn supplementation tended to lower (P = 0.06) LT pH compared with non–Zn-supplemented steers. LT from RAC-fed steers had a greater pH (P = 0.04) 6 h PM than non–RAC-supplemented steers. RAC supplementation resulted in a greater (P < 0.01) WBSF, and Zn supplementation tended for a lower (P = 0.06) WBSF at 1 d PM compared with non–RAC-supplemented and non–Zn-supplemented samples, respectively. RAC supplementation resulted in less desmin (P = 0.05) and troponin-T (P = 0.04) degradation at 1 d PM compared with non–RAC-supplemented samples. Differences in glycolytic, fatty acid, and other energy metabolites were identified (Table 1). SUPZN-NO had less AMP deaminase and greater malate dehydrogenase than CON-NO or SUPZN-RAC. SUPZN-NO had greater pyruvate dehydrogenase subunit beta than CON-NO or CON-RAC. CON-RAC had more fructose bisphosphate aldolase and glyceraldehyde phosphate dehydrogenase than CON-NO or SUPZN-RAC.

Conclusion: Differences in glycolytic metabolites and enzymes represent explanations for variations in LT pH early PM. Fatty acid metabolites could represent differences in use of the beta oxidation pathway for energy production in CON-RAC and SUPZN-NO. Greater sorbitol in SUPZN-NO represents shifts to the polyol pathway in PM energy production influencing a lower pH at 6 h PM and lower WBSF values at 1 d PM. These metabolic profile differences demonstrate the influence of nutritional management on meat quality development.

Keywords: beef, metabolism, metabolome, pH decline, proteome

137 MITOCHONDRIA MORPHOLOGY IN POSTMORTEM LONGISSIMUS LUMBORUM OF ANGUS AND BRAHMAN

B. Hawryluk^1*, P. Ramos¹, K. Kelley², and T. Scheffler¹, ¹Department of Animal Sciences and ²Interdisciplinary Center for Biotechnology Research–Electron Microscopy Core, University of Florida, Gainesville, Florida, USA, *tscheffler@ufl.edu

Objectives: Mitochondria (Mt) have the potential to contribute to early postmortem metabolism, which could affect proteolysis and meat quality. Previously, we showed that Mt function in longissimus lumborum (LL) declines during the first 24 h postmortem, and Brahman Mt sustain function longer than Angus. The objective of this study was to assess ultrastructural morphology of Mt in LL postmortem using transmission electron microscopy.

Materials and Methods: Angus and Brahman steers (n = 14 per breed) were reared in similar conditions and harvested at approximately 19 mo of age. Samples of LL were collected at 1, 3, 6, and 24 h postmortem, sliced with a razor blade, and cut into 1 mm³ cubes. Samples were treated with a fixing solution, dehydrated with ethanol, and placed in LR-White resin to cure. The samples were placed into grids and stained sequentially with 1% sodium metaperiodate, 2% uranyl acetate, and 3% lead citrate. A subset of samples (Angus, n = 4; Brahman, n = 5; 1 and 24 h) were then examined under the transmission electron microscope and scanned in at least 3 different sections per grid. Images of intermyofibrillar and subsarcolemmal Mt were taken. Only Mt with a defined outer membrane were evaluated and quantified using Fiji-ImageJ. Mitochondria were analyzed for circularity, roundness, surface area (μm²), perimeter (μm), optical density (0 = white, 1 = black; describes matrix density), Feret’s diameter (μm; longest distance between 2 points), and aspect ratio. Data were analyzed in JMP Pro 15.0 using a mixed model with fixed effects of breed (b), time (t), and their interaction (b×t). Time was considered a repeated measure.

Results: Circularity, roundness, surface area, perimeter, optical density, Feret’s diameter, and aspect ratio were not affected by breed (b, P > 0.1) or the interaction (b × t, P > 0.1). However, time influenced surface area (P < 0.05), perimeter (P < 0.05), and Feret’s diameter (P < 0.05) with greater values at 24 h. Optical density tended to differ by time (P = 0.07), with lower values at 24 h.

Conclusion: Breeds exhibited similar trends in Mt shape and matrix density. However, the increased surface area, perimeter, and Feret’s diameter from 1 to 24 h postmortem evidence Mt swelling. The lower optical density at 24 h is also consistent with Mt swelling, indicating increased permeability of inner and outer membranes. Analysis of Mt at 3 and 6 h is needed to establish progression of morphological changes and their relationship with Mt functional parameters and proteolysis between breeds.

Keywords: mitochondria, transmission electron microscopy

138 NUTRIGENOMICS: AVAILABILITY OF BEEF-DERIVED MICRORNA AFTER DIGESTION MAY MODULATE GENE EXPRESSION AFTER MEAT CONSUMPTION

F. Giotto^1*, M. Li², T. Zhou², B. Ferguson³, and A. S. De Mello¹, ¹Agriculture, Veterinary, and Rangeland Sciences, ²Phisiology and Cell Biology, and ³Nutrition, University of Nevada, Reno, Nevada, USA, *ademello@unr.edu

Objectives: MicroRNA (miR) are small single-stranded non-coding RNA with an average of 22 nucleotides in length, which are known to silence genes and/or inhibit protein translation. These RNA are unique, as miR are resistant to aging and cooking, possibly due to the protection against denaturation offered by the miR-induced silencing complex comprising Argonaute and other proteins. In this study, we evaluated the effects of cooking and in vitro digestion on the availability of beef-derived miR to determine whether they may be available at the duodenum for further absorption.

Materials and Methods: Longissimus lumborum steaks were removed from 4 (n = 4) crossbred steers 15 min postmortem, aged for 14 d and cooked and digested. Steaks were cooked until temperature reached 158°F, and an aliquot of approximately 2 g was digested with pepsin and trypsin to mimic human digestion. RNA was extracted and isolated from samples via Triazol. All samples were quantified and measured for RNA integrity via BioAnlyzer 2100 (Agilent, Santa Clara, CA). Barcoded miRNA-Seq libraries were prepared using the NEXTflex Small RNA Sequencing v3 kit (Bioo Scientific, Austin, TX) with randomized adapters according to the recommendations of the manufacturer. The fragment size distribution of the libraries was verified via micro-capillary gel electrophoresis on a Bioanalyzer 2100 (Agilent, Santa Clara, CA). The libraries were quantified by fluorometry on a Qubit instrument (LifeTechnologies, Carlsbad, CA) and pooled in equimolar ratios. Sixteen libraries were sequenced on one lane of a HiSeq 4000 sequencer (Illumina, San Diego, CA) with single-end 100 bp reads. Data were summarized by the SPORTS computational pipelines. Counts per million (CPM) were used as the unit for expression. Differentially expressed miRNA were identified by the edgeR tool.

Results: As expected, here was a decreased expression for many miR, but these non-coding RNA did not disappear completely, suggesting resistance to cooking and digestion. Unexpectedly, several miR had significantly increased expression in digested beef compared with fresh beef (P < 0.05). A total of 413 miRBase registered bos taurus miR were detected in digested samples. MicroRNA with highest logCPM counts in digested samples were as follows: bta-miR-1-2 (26.97%), bta-miR-1-1 (26.97%), bta-miR-451 (8.66%), bta-miR-486 (6.97%), bta-miR-143 (1.78%), bta-miR-92a-1 (1.77%), bta-miR-133a-2 (1.69%), bta-miR-133a-1 (1.68%), bta-miR-92a-2 (1.54%), and bta-miR-22 (1.37%). Higher expression levels of bta-miR 1434, 760, 1484, 193-b, 345, 677, 1248-1, 1248-2, 1296, 1307, 320a-1, and 320a-2 were observed in digested when compared with fresh beef.

Conclusion: Predictions between 90 and 100 suggest that human homologous miR hsa-miR-1-3p and hsa-miR-1-5p may modulate the expression of 190 genes associated to several metabolic pathways. Therefore, bta-miR-1-2 and bta-miR-1-1 may also modulate human genes. Target scores above 80 suggest that modulations are likely to be real. This supports the hypothesis that miR play an important role in nutritional values of meats if they are absorbed in the intestines. In vivo studies are currently underway to confirm that miR can be absorbed, reach the blood stream, and modulate the expression of inflammatory (e.g., IL-6) and metabolic genes (e.g., PEPCK) in the gut and associated tissues such as the liver.

Keywords: beef, microRNA, nutrigenomics

139 EXPLORING THE POTENTIAL EFFECT OF ANTI-PHOSPHOLIPASE A2 ANTIBODY TO EXTEND BEEF SHELF LIFE IN A BEEF LIPOSOME MODEL SYSTEM

C. Chun^1*, R. Welti², M. Roth², M. Richards³, and M. Chao¹, ¹Department of Animal Sciences and Industry and ²Division of Biology, Kansas State University, Manhattan, Kansas, USA; ³Animal and Dairy Sciences, University of Wisconsin–Madison, Madison, Wisconsin, USA, *ckychun@ksu.edu

Objectives: Phospholipase-A₂ (PLA2) is a ubiquitous enzyme that cleaves a fatty acid tail at the sn-2 position from a phosphatidylcholine (PC), an abundant phospholipid (PL) class in cell membranes. The resulting free fatty acids are typically polyunsaturated fatty acids which are prone to lipid oxidation when exposed to pro-oxidants such as light and oxygen. A PLA2 antibody (aPLA2) can be mass produced through laying hens, and the egg powder containing aPLA2 has been used as a feed supplement to improve growth performance for various livestock. We hypothesize that the aPLA2 from the egg powder may inhibit PLA2 activity, preventing the formation of free fatty acids, which can potentially improve the shelf stability of beef. Therefore, the objective of this study was to utilize a beef liposome model system to investigate this proposed mechanism.

Materials and Methods: Total lipid was extracted from 10 USDA choice beef loins at 3 d postmortem. The PL was separated from each lipid pool through solid phase extraction. The PL from each steak was further split into 6 different treatments: (1) PL (10 mg/mL of PL); (2) aPLA10 (PL + 10 ug/mL of aPLA2); (3) aPLA20 (PL + 20 ug/mL of aPLA2); (4) PLA2 (PL + 4 ug/mL of PLA2); (5) PLA2 + aPLA10 (PL + PLA2 + 10 ug/mL of aPLA2); (6) PLA2 + aPLA20 (PL + PLA2 + 20 ug/mL of aPLA2). Treatments were mixed with a tris/CaCl₂ buffer and incubated at 37°C for 2 h to activate PLA2. After the incubation, an aliquot was immediately taken for PL profile analysis by mass spectrometry. Eighty μM of bovine myoglobin was added to the remaining samples and exposed to retail display conditions (4°C; 2,300 lx) for 7 d. At 0, 1, 4, and 7 d, aliquots were taken for lipid oxidation analysis.

Results: There was a display × treatment interaction for lipid oxidation (P < 0.01). At 7 d display, PLA2, PLA2 + aPLA10, and PLA2 + aPLA20 treatments had greater lipid oxidation compared with the samples without PLA2. Interestingly, not only did 7-d aPLA10 and aPLA20 have less lipid oxidation than PL only and all PLA2 treatments, but 7-d aPLA10 and aPLA20 also had less oxidation compared with 4-d PLA2 (P < 0.01). This trend continued to be seen in the other retail display periods. As expected, PL profile analysis showed clear differences between treatments with or without PLA2. The PLA2 treatments showed greater relative percentage of total lysophosphatidylcholine (LPC) and LPC 16:0, 16:1, 18:0, and 18:1 than treatments without PLA2 (P < 0.01). The PLA2 treatments had significantly less relative percentage of total ether-linked PC (ePC) than treatments without PLA2, specifically ePC34:1, 34:2, 34:4, 36:1, 36:3, and 36:4 (P < 0.05). Interestingly, the PLA2 treatments did not seem to have significant effect on relative percentage of total PC as seen in ePC. Finally, it appears that aPLA2 had no effect on inhibiting PLA2 hydrolysis as there was no difference between PLA2 and aPLA + PLA2 treatments in relative percentage of total ePC or PC nor in LPC composition (P > 0.10).

Conclusion: This study confirmed that the hydrolysis of PL by PLA2 influenced lipid oxidation. Although no inhibition effect was observed for PLA2 by aPLA2, there appears to be an antioxidant effect for aPLA2 for lipid oxidation. On the other hand, PLA2 appears to attack ePC more effectively than PC. Perhaps a product ion analysis to reveal the fatty acid composition for each PL species could help explain the reasoning behind why ePC was hydrolyzed more than the traditional ester-bonded PC.

Keywords: beef, lipid oxidation, lipidomic, Phospholipase A2, phospholipid

140 UTILIZING A VIRTUAL INDUSTRY WORKSHOP TO ASSESS THE INSTRUCTIONAL EFFECTIVENESS OF A MEAT PROCESSING COURSE

W. N. Osburn^1* and C. Quinlan², ¹Animal Science, Texas A&M University, College Station, Texas, USA; ²Research and Development, Tyson Foods, Springdale, Arkansas, USA, *osburnw@tamu.edu

Objectives: The objective of this project was to use a virtual industry workshop to assess the instructional effectiveness of a meat processing course via student participation and student survey feedback.

Materials and Methods: Beyond Fresh Meats (BFM; Tyson) was used to assess the instructional effectiveness of an undergraduate/graduate cross-listed (Animal Science and Food Science) meat processing course (ANSC/FSTC 447/667 Industrial Processed Meat Operations [IPMO]). Students (N = 7) had been exposed to functional properties of proteins/lipids, ingredient technology, comminuted, restructured and whole muscle products, marination/injection, thermal processing, batter and breader processing, and product development prior to BFM. BFM objectives were to utilize current ingredients, processes, and equipment to gain a deep understanding of marination and batter/breading in poultry and red meat products and to provide students an industry perspective and exposure to what a career in R&D entails. BFM was conducted in 5 lecture/lab modules with support packages (seasonings, raw materials, finished products, etc.). BFM modules were as follows: Module 1: Processing Lecture/Virtual Plant Tour; Module 2: Functional Ingredients & Poultry Raw Materials; Module 3: Flavors, Seasonings, Marination; Module 4: Batter and Breading and Module; Module 5: Cross Functional Team Engagement. Students participated in BFM lectures at the designated times, and BFM lab activities were conducted during 2 IPMO lab times (Lab 1: Modules 1/2; Lab 2: Modules 3/4/5). Surveys were emailed to students after the conclusion of BFM. Students were asked to respond to questions on a 1–5 scale: 1 = Strongly disagree and 5 = Strongly agree. The survey posed questions for each BFM module on how well IPMO prepared them for each BFM module and whether information/activities should be included in IPMO. Surveys were anonymous.

Results: For Module 1, students indicated that virtual tours should be a part of ANSC 467/667 (4.43). Students specified that IPMO lecture and lab information helped them understand the information provided in BFM Module 2 (5.00 and 4.86) and Module 3 (4.71 and 4.86) (lecture and lab, respectively). Students stated that BFM Module 2 information on Poultry Raw Materials should be included in IPMO (4.14). Slightly lower values were observed for BFM Module 4, for which students’ average rating was 4.57 (lecture) and 4.00 (lab). Students rated IPMO as 4.71 (lecture) and 5.00 (lab) for Module 5, which included information about sensory protocols, regulatory and nutritional requirements, and collaboration sales/marketing for developing new products. This was possibly due to the IPMO team R&D projects the students were engaged in. Survey data showed that participation in the virtual BFM course enhanced student understanding of processed meat operations (4.86). Students indicated that BFM enhanced their understanding of information/concepts presented in IPMO (4.57) and that the use of virtual demonstrations should be included in IPMO (4.43).

Conclusion: BFM enhanced students’ knowledge and understanding of processed meat manufacturing. Course improvements to IPMO should focus on providing more information/labs on poultry raw materials and batter and breaded products. The research and development team project should remain as the class capstone event. Development of virtual demonstrations (used as a pre-lab activity) would enhance student learning.

Keywords: assessment, Beyond Fresh Meats, instruction, meat processing