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Effects of antimicrobial coatings and cryogenic freezing on survival and growth of Listeria innocua on frozen ready-to-eat shrimp during thawing

Guo, Mingming, Jin, Tony Z., Scullen, O. Joseph, Sommers, Christopher H.
Journal of food science 2013 v.78 no.8 pp. 1195
Listeria innocua, Listeria monocytogenes, allyl isothiocyanate, antibacterial properties, bacterial contamination, coatings, food contamination, food pathogens, freezing, frozen foods, frozen storage, microbial growth, pathogen survival, product safety, ready-to-eat foods, risk, shrimp, synergism, temperature, thawing
Foodborne pathogens such as Listeria monocytogenes could pose a health risk for frozen ready-to-eat (RTE) shrimp as the pathogen can grow following thawing. In this study, antimicrobial coating treatments alone, or in combination with cryogenic freezing, were evaluated for their ability to inhibit the growth of Listeria innocua, a surrogate for L. monocytogenes, on RTE shrimp during thawing. Cooked RTE shrimps were inoculated with L. innocua at three population levels and treated with coating solutions consisting of chitosan, allyl isothiocyanate (AIT), or lauric arginate ester (LAE). The treated shrimp were then stored at -18C for 6 days before being thawed at 4, 10, or 22C for either 24 or 48 h. Results revealed that antimicrobial coatings achieved ca. 5.5 to 1 log CFU/g reduction of L. innocua on RTE shrimp after the treatments, depending on inoculated population levels. The coating-treated shrimp samples had significantly (p less than0.05) less L. innocua than controls at each thawing temperature and time. Additional cryogenic freezing to coating treatments did not achieve synergistic effects against L. innocua. Antimicrobial coatings can help to improve product safety by reducing Listeria on RTE shrimp.