Modeling the survival and growth of Escherichia coli O157:H7 and Salmonella enterica serovar Typhimurium inoculated on lettuce after dipping in a chlorine-based disinfectant/sanitizer as a function of different storage temperatures

This study aimed at developing predictive models for Escherichia coli O157:H7 and Salmonella enterica serovar Typhimurium on lettuce stored at 5, 15, 25, and 35℃ before and after dipping in 200 ppm sodium hypochlorite (NaOCl), using the Gompertz-derive survival and growth kinetics. Regardless of the conditions under which the cells of E. coli O157:H7 or S. Typhimurium grew, higher storage temperatures led to a shorter time required to reach 5 log CFU/g. An increase in storage temperature had a positive effect on growth rates (GRs), and the GRs were significantly (p<0.05) higher at 35℃ than those at 5, 15, and 25℃. Accuracy factors (1.008-1.233) and bias factors (0.811-1.142) were in the acceptable ranges, thereby demonstrating the applicability of the proposed models for predicting the behavior of E. coli O157:H7 and S. Typhimurium on lettuce treated with NaOCl under the tested storage conditions.