Modeling Salmonella Growth in Irradiated Pork for Specific Target Groups and Patients at Isothermal and Dynamic Temperature

Abstract

This study developed mathematical models to predict Salmonella enterica growth in irradiated pork for specific target groups and immunocompromised patients under constant and dynamic temperature conditions. Irradiated fresh pork slices were prepared by gamma-irradiation at 40 kGy, and inoculated with Salmonella followed by storage at 4 degrees C, 15 degrees C, 25 degrees C, and 35 degrees C up to 240 h, depending on storage temperature. Salmonella cell counts were enumerated on tryptic soy agar during storage. For calculation of maximum specific growth rate (Log CFU/cm(2)/h), lag phase duration (h), lower asymptote (Log CFU/cm(2)), and upper asymptote (Log CFU/cm(2)), the Baranyi model was fitted to the bacterial cell counts. The model parameters were then further expressed as a function of storage temperature (R-2: 0.8-0.992). In addition, a dynamic model was also developed to. predict Salmonella growth at changing temperature. Mathematical indices showed that the model had good performance with 1.011 and 1.04 for bias and accuracy factors, respectively, under constant temperature. In addition, graphical comparison showed that Salmonella growth simulation under changing temperature was acceptable. The results indicate that the developed models should be useful in predicting Salmonella growth in irradiated fresh pork, which could be used for special target groups and immunocompromised patients.