Mathematical models to predict kinetic behavior and growth probabilities of listeria monocytogenes on pork skin at constant and dynamic temperatures

Abstract

In this study, mathematical models were developed to predict the growth probability and kinetic behavior of Listeria monocytogenes on fresh pork skin during storage at different temperatures. A 10-strain mixture of L. monocytogenes was inoculated on fresh pork skin (3 by 5 cm) at 4 log CFU/cm 2. The inoculated samples were stored aerobically at 4, 7, and 10°C for 240 h, at 15 and 20°C for 96 h, and at 25 and 30°C for 12 h. The Baranyi model was fitted to L. monocytogenes growth data on PALCAM agar to calculate the maximum specific growth rate, lag-phase duration, the lower asymptote, and the upper asymptote. The kinetic parameters were then further analyzed as a function of storage temperature. The model simulated growth of L. monocytogenes under constant and changing temperatures, and the performances of the models were evaluated by the root mean square error and bias factor (B f). Of the 49 combinations (temperature | sampling time), the combinations with significant growth (P