Validation of growth models for Listeria monocytogenes and Yersinia enterocolitica in cooked chicken meat

In this study, growth rate models of the Listeria monocytogenes and Yersinia enterocolitica were compared in cooked chicken meat. The chicken meat was inoculated with the pure culture or mixed Cultures of these pathogens and stored at 4-34 degreesC. After the growth curves of these two pathogens were obtained, the modified Gompertz function was then fitted to the experimental curves. The parameter of specific growth rate was described by the Zwietering model. The models predicting the growth for these pathogens in chicken meat and parameters generated by pathogens modeling program (PMP) were then compared using the mathematical and statistical parameters Such as mean square error (MSE), regression coefficient (R-2), bias factor, and accuracy factor. The Zwietering model was found to be suitable for predicting the specific growth rate of L. monocytogenes and Y. enterocolitica in the chicken meat and parameters generated by PMP. In addition. the predicted value for the pathogens in the PMP was higher than that in the chicken meat. No growth was observed when L. monocytogenes was inoculated in chicken meat and stored at 4 degreesC. In the presence of Y. enterocolitica, the growth of L. monocytogenes was competitively inhibited in chicken meat at the temperatures ranging front 10-34 degreesC.