Identifying Ingredients That Delay Outgrowth of Listeria monocytogenes in Natural, Organic, and Clean-Label Ready-to-Eat Meat and Poultry Products

Abstract

The objective of this study was to identify ingredients that inhibit Listeria monocytogenes in natural, organic, or clean-label ready-to-eat meat and poultry products. Fourteen ingredients were screened in uncured (no-nitrate-or-nitrite-added), traditional-cured (156 ppm of purified sodium nitrite), cultured (alternative cured, natural nitrate source, and Staphylococcus carnosus), or preconverted (alternative cured, natural nitrite source) turkey slurries. Slurries were cooked, cooled, inoculated to yield 3 log CFU/ml L. monocytogenes, stored at 4°C, and tested weekly for 4 weeks. Three antimicrobial ingredients, 1.5 % vinegar-lemon-cherry powder blend, 2.5 % buffered vinegar, and 3.0 % cultured sugar-vinegar blend, were incorporated into alternative-cured ham and uncured roast beef and deli-style turkey breast. Controls included all three meat products without antimicrobial ingredients and a traditional-cured ham with 2.8 % sodium lactate-diacetate. Cooked, sliced products were inoculated with 3 log CFU/g L. monocytogenes, vacuum packed, and stored at 4 or 7°C, for up to 12 weeks. For control products without antimicrobial agents stored at 4°C, a 2-log L. monocytogenes increase was observed at 2 weeks for ham and turkey and at 4 weeks for roast beef. Growth (>1-log increase) in the sodium lactate-diacetate was delayed until week 6. Compared with the control, the addition of either vinegar-lemon-cherry powder blend or buffered vinegar delayed L. monocytogenes growth for an additional 2 weeks, while the addition of cultured sugar-vinegar blend delayed growth for an additional 4 weeks for both ham and turkey. The greatest L. monocytogenes delay was observed in roast beef containing any of the three antimicrobial ingredients, with no growth detected through 12 weeks at 4°C for all the treatments. As expected, L. monocytogenes grew substantially faster in products stored at 7°C than at 4°C. These data suggest that antimicrobial ingredients from a natural source can enhance the safety of ready-to-eat meat and poultry products, but their efficacy is improved in products containing nitrite and with lower moisture and pH.

Utilization of Buffered Vinegar to Inhibit the Growth of Listeria monocytogenes on Marinated and Cooked Chicken Breast

“…However, in their study, the 0.4% dry vinegar treatment was not effective at controlling Listeria growth. These results are also in agreement with results reported by McDonnell et al (2013) and Gonzalez-Fandos and Herrera (2014). These researchers reported that the antimicrobial effect of vinegar and other natural or cleanlabel antimicrobials is impacted by the concentration that is included in the product.…”

Inhibition of Listeria monocytogenes in Deli-Style Turkey Breast Formulated with Cultured Celery Powder and/or Cultured Sugar–Vinegar Blend during Storage at 4°c

“…Subsequent studies have confirmed that nitrite also enhances the antilisterial effect of other conventional antimicrobials, such as potassium sorbate, sodium propionate, and sodium benzoate, particularly when used in RTE meat products with lower moisture or pH values (8,10,16,24). In this study, populations of L. monocytogenes increased by >1 log CFU/ ml on uncured turkey supplemented with 3.8% KL-SD alone and stored 6 weeks at 4°C, but a < l-lo g mean increase was observed in turkey supplemented with 3.8% KL-SD and 80 ppm of nitrite and stored at the same temperature for 12 weeks.…”

“…Nine test fonnulations (Table 1) o f deli-style turkey breast were manufactured using good manufacturing practices in the Meat Science and Muscle Biology Laboratory (University of W isconsin-M adison) essential ly as previously described (16). An additional uncured control formulation containing no nitrite or antimicrobials (treatment 10) also was included.…”

“…However, many consumers believe that additivefree or natural versions of foods are more healthful, which has stimulated growth in the natural and organic foods sector (3, 1 7 ). I n response to this market trend, the industry has focused efforts on production of ready-to-eat (RTE) meat and poultry products, which could be considered clean label and naturally cured but retain similar microbial safety characteristics as conventionally prepared products (16,31).…”

“…When used at concentrations within regulatory limits, nitrite will slightly inhibit but not prevent growth of L. monocytogenes unless used in combination with an adjunct antimicrobial such as lactate, diacetate, propionate, or benzoate (7-9, 15, 23, 24, 28, 30). However, to be consistent with clean label ingredient statements, an array of microbial fermentates, organic acid blends, and plant extracts are being investigated as antilisterial alternatives (16,32). We hypothesized that when products are standardized for ingoing nitrite concentration, moisture, pH, and salt, the nitrite derived from a natural source will provide antilisterial activity equivalent to that of purified nitrite.…”