Reciprocal Meat Conference Abstracts

Inhibition of Listeria Monocytogenes and Spoilage Bacteria on Cured Ready-to-Eat Meats by Sodium-Free and Clean-Label Antimicrobial Ingredients

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Abstract

ObjectivesTo compare the inhibitory properties of a standard potassium acetate and diacetate blend (Provian K) and a natural fermented and neutralized dry vinegar product (Provian NDV)on the growth of both Listeria monocytogenes and lactic acid bacteria in cured RTE meats.Materials and MethodsFive treatments of cured deli-style ham (72 to 74% moisture, 1.75 ± 0.1% salt, and pH 6.2 to 6.4, 156 mg/kg sodium nitrite and 547 mg/kg sodium erythorbate)where tested, including a control without antimicrobials and different concentrations of Provian K (0.5 and 0.75%) and Provian NDV (0.5%, 0.65%). Cooked products were surface-inoculated with 3-log10 CFU/g of a cocktail of 5 strains of Listeria monocytogenes (including serotypes 4b, 1/2a and 1/2b) or a mixture of 2 lactic acid bacteria (LAB) strains including Carnobacterium divergens and Leuconostoc mesenteroides, both isolated from spoiled cooked meat products. Inoculated slices (100 g/package) were vacuum-packaged and stored at different temperatures for up to 4 and 8 wk, for LAB and L. monocytogenes, respectively. Triplicate samples per treatment were assayed by enumerating twice on modified Oxford Agar for L. monocytogenes and on Plate Count agar (30°C, 48 h) and APT agar with bromocresol purple (27°C, 48 h) for LAB. The study was conducted twice.ResultsResults on Listeria inhibitionControl Ham supported > 1 log increase of L. monocytogenes at 4 and 2 wk storage at 4°C and 7°C, respectively (Fig. 1). In contrast, hams supplemented with 0.5 or 0.75% Provian K or 0.65% NDV inhibited the Listeria growth for 12 and 8 wk at 4 and 7°C, respectively. Inhibition of Listeria on ham supplemented with 0.5% NDV was further affected by pH and moisture. Ham supplemented with 0.5% Provian NDV in the trial 1 (71.5% moisture, pH 6.2) delayed Listeria for 12 wk storage at 4°C, whereas individual samples of trial 1 (72.9% moisture, pH 6.3) supported growth (> 1 log increase) at 8 wk. Similar trends were observed at 7°C.Results on Lactic Acid Bacteria inhibitionThe Control Ham supported the increase of Lactic acid bacteria to spoilage level (> 6 Logs) at 3 and 2 wk storage at 4°C and 7°C, respectively. In contrast, hams supplemented with 0.5% Provian K or 0.8% Provian NDV showed complete inhibition of LAB for 4 wk. For complete inhibition at 7°C slight higher concentrations of 0.75% and 1% were needed of Provian K and Provian NDV, respectively.ConclusionThe results of this study show the inhibitive effect of a natural fermented vinegar product on the growth of Listeria monocytogenes and Lactic acid bacteria in a cured ready-to eat ham. To have a comparable efficacy with neutralized natural vinegar as with a standard acetate-diacetate product, the dosage of the vinegar based product should be increased by approximately 10%. This can be explained by the lower amount of undissociated acid in the product.

Keywords: natural preservation, food safety, Listeria control, sodium reduction, shelflife extension

How to Cite:

Heintz, E., Vega, L. & Jahr, G., (2018) “Inhibition of Listeria Monocytogenes and Spoilage Bacteria on Cured Ready-to-Eat Meats by Sodium-Free and Clean-Label Antimicrobial Ingredients”, Meat and Muscle Biology 2(2). doi: https://doi.org/10.221751/rmc2018.122