Files
Abstract
Listeria monocytogenes is a hardy psychotropic pathogen that has been historically linked to soft and fresh cheese related outbreaks in the U.S. This study developed mathematical models that can predict the growth of L. monocytogenes in queso fresco. Samples of freshly prepared queso fresco were vacuum-packaged and stored at 4, 10, 15, 20, 25 and 30C. The Baranyi and Ratkowsky square root models were fitted to the growth data at each temperature as the primary and secondary model, respectively. These primary and secondary models provided coefficient of determination values of R2=0.93 and 0.97, respectively. Tertiary models for non-isothermal profiles were developed and validated with the Acceptable Prediction Zone (APZ) method. Greater than 70% of the observations were within the APZ (0.5>Prediction Error>-1.0). These predictions will help in estimating the risk of listeriosis due to possible extended storage with temperature abuse scenarios for queso fresco.