title: 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.
authors.affiliation: Food Research Institute, University of Wisconsin-Madison, 1925 Willow Drive, Madison, Wisconsin 53706, USA.
authors.forename: Lindsey M
authors.initials: LM
authors.lastname: McDonnell
authors.forename: Kathleen A
authors.initials: KA
authors.lastname: Glass
authors.forename: Jeffrey J
authors.initials: JJ
authors.lastname: Sindelar
mesh_terms: D000085:Acetates / Q000494:pharmacology; D019342:Acetic Acid / Q000494:pharmacology; D000818:Animals; D015169:Colony Count, Microbial; D003257:Consumer Product Safety; D005506:Food Contamination / Q000032:analysis / Q000517:prevention & control; D005516:Food Microbiology; D005519:Food Preservation / Q000379:methods*; D005520:Food Preservatives / Q000494:pharmacology*; D006801:Humans; D007773:Lactates / Q000494:pharmacology; D008089:Listeria monocytogenes / Q000187:drug effects / Q000254:growth & development*; D008461:Meat Products / Q000382:microbiology*; D011202:Poultry Products / Q000382:microbiology*; D019354:Sodium Lactate / Q000494:pharmacology; D012977:Sodium Nitrite / Q000494:pharmacology; D014618:Vacuum
chemical_list: D000085:Acetates; D005520:Food Preservatives; D007773:Lactates; C548838:sodium diacetate; D012977:Sodium Nitrite; D019342:Acetic Acid; D019354:Sodium Lactate