Predictive Modeling for the Growth of Listeria monocytogenes and Salmonella Typhimurium on Fresh-cut Cabbage at Various Temperatures

Abstract

The growth of Listeria monocytogenes and Salmonella Typhimurium on fresh-cut cabbage at between 15 and 35 degrees C before and after treatment with water washing, chlorine dipping, and chlorine dipping followed by water washing were investigated. It is apparent that these pathogens could grow faster at higher temperature. Chlorine treatments reduced L. monocytogenes and S. Typhimurium on cabbage by 1.04-1.15 log CFU/g and 1.35-1.51 log CFU/g, respectively. Gompertz model and polynomial equation were used to describe the behaviors of L. monocytogenes and S. Typhimurium on cabbage before and after treatment with water washing, chlorine dipping, and chlorine dipping followed by water washing as a function of temperature. The lag times of L. monocytogenes and S. Typhimurium were the longest when treated with chlorine dipping followed by water washing at 15 degrees C. The growth rates of L. monocytogenes and S. Typhimurium were the lowest when treated with water washing at 15 degrees C, indicating that the growth of pathogen was more affected by storage temperature than chlorine treatment. Validation was also performed to evaluate the reliability of developed predictive models. The B-f values of the growth rate and lag time for L. monocytogenes and S. Typhimurium ranged from 0.90 to 1.25, indicating that they were mostly in the acceptable level, whereas A(f) values ranged from 1.07 to 1.80, showing that they were over-predicted.