Modeling growth kinetics of Listeria monocytogenes in pork cuts from packaging to fork under different storage practices

The fate of Listeria monocytogenes in fresh meat products during transport and storage at retail and then at the consumer's house is poorly understood. In this study microbial behavior and concentration of L. monocytogenes in ten lots of naturally contaminated loin chops have been evaluated under four different storage scenarios throughout the product shelf life. Between-and within-lot variability on loin chops, as well as impact of environmental temperatures on pathogen growth were investigated. Secondly, distributions of the microbial concentration in the naturally contaminated lots were fitted using the maximum likelihood estimation (MLE) and variability in growth potential at dynamic storage was assessed by applying a validated predictive model from the literature, together with MonteCarlo simulation techniques. The results show that model estimations are consistent to the observed data even though variability in the growth kinetic parameters impacts the growth of L. monocytogenes in loin chops throughout the product shelf life. Overall, storage at mean refrigerator temperatures did not increase the populations of L. monocytogenes over 2 log colony forming unit per gr (cfu/g). In contrast, final storage at abuse temperatures produced microbial counts greater than 3 log cfu/g for some lots, which would require a more severe heat inactivation treatment before consumption. The results of this study should be used by risk managers to predict the effect of cooking in pathogen inactivation in loin chops, as well as the risk of cross contaminations.