VALIDATION OF PREDICTIVE MATHEMATICAL-MODELS DESCRIBING THE GROWTH OFLISTERIA-MONOCYTOGENES

Growth of Listeria monocytogenes and Listeria innocua in commercially available sterile homogeneous foods was investigated at different temp eratures, pH values, and NaCl concentrations. Growth data were fitted to the Gompertz equation and the resulting growth kinetics were compar ed with predictions from the Pathogen Modeling Program and Food MicroM odel. In general, good agreement was obtained when comparing growth ra tes and generation times for both models. Differences were observed wh en comparing lag phases, which ranged from 117 h shorter to 4.9 h long er than predicted for L. monocytogenes. Despite differences in lag pha se, under most conditions, the models gave good predictions of microbi al growth. Predictive modeling appears to be a useful tool in determin ing growth rates of Listeria in foods.