Inhibition of Listeria monocytogenes and Clostridium botulinum in Uncured Shredded Pork and Turkey Packaged Under Reduced Oxygen Conditions

• Published in: Journal of food protection 2024-06, Vol.87 (6), p.100271-100271, Article 100271
• Main Authors: Glass, Kathleen A., Golden, Max C., Wanless, Brandon J., Conklin, Tina, Schweihofer, Jeannine P., Schill, Kristin M.
• Format: Article
• Language: English
• Subjects: Animals; Clean label antimicrobials; Clostridium botulinum; Clostridium botulinum - drug effects; Colony Count, Microbial; Food Contamination - analysis; Food Microbiology; Food Packaging - methods; Food Preservation - methods; Humans; Listeria monocytogenes; Listeria monocytogenes - drug effects; Meat Products - microbiology; Oxygen; Ready-to-eat pork; Ready-to-eat turkey; Swine; Temperature; Turkeys
• ISSN: 0362-028X; 1944-9097
• DOI: 10.1016/j.jfp.2024.100271

•Shredded turkey and pork supported Listeria monocytogenes growth in 2 weeks at 7.2°C.•Control treatments supported botulinum toxin production at 2 weeks at 12.8°C.•Addition of 2% dry cultured dextrose-vinegar-rosemary delays the growth of Listeria monocytogenes.•Natural variation in product pH impacts Listeria monocytogenes growth rate.•Reducing product pH to 5.5 with citric acid further enhances pathogen inhibition. Cooked, uncured meat products packaged under reduced oxygen packaging conditions require the control of anaerobic and facultative anaerobic pathogens if they are held at temperatures greater than 3°C at retail or consumer level. The objective of this study was to determine the inhibition of Listeria monocytogenes and Clostridium botulinum in cooked, uncured shredded turkey and pork formulated with synthetic or clean-label antimicrobials. Treatments of shredded meat products were prepared with or without antimicrobials using turkey thigh or breast that were cooked to 85°C, shredded, and chilled before inoculation with the target pathogen. L. monocytogenes inoculated samples were stored at 7.2°C, whereas C. botulinum samples were stored at 12.8°C; triplicate samples were assayed every 2 weeks. In the first set of experiments, L. monocytogenes populations increased 2 to 3 logs within 2 weeks of storage at 7.2°C in both meat control treatments without antimicrobials and in pork with 4% lactate-diacetate blend (LD). A 1-log increase was observed in turkey with 4% LD and Pork with 2% cultured dextrose-vinegar-rosemary (CDVR) under the same storage conditions; a 1-log increase was observed in turkey with CDVR at 4 weeks. The second set of experiments tested the effect of pH reduction (to less than 5.5 by the addition of 0.5% citric acid) in combination with 2% CDVR when added to the brine precook or postcook during shredding. Populations of L. monocytogenes increased 4-log within 2 and 4 weeks at 7.2°C for the control turkey and pork formulations, respectively. No growth was observed in 12 weeks for any antimicrobial CDVR-CA treatments regardless of how antimicrobial was added. Similarly, botulinum toxin was detected in both control treatments at week 2 at 12.8°C, but no toxicity was observed in either antimicrobial treatment through 12 weeks. These data suggest that a combination of 2% cultured dextrose-vinegar-rosemary extract plus 0.5% citric acid to reduce pH inhibits the growth of L. monocytogenes and toxin production of C. botulinum in uncured