Thermal inactivation model of Listeria monocytogenes in ground beef

Abstract:

Abstract: [Objective] To set up suitable kinetic models for the evaluation of heat inactivation rate of Listeria monocytogenes in ground beef. [Methods] Ground beef, inoculated with 3 strains of L. monocytogenes, was subjected to heating at 55℃, 57.5℃, 60℃, 63℃, 66℃ or 70℃ to develop the isothermal kinetic models. The survival curves were fitted with modified Gompertz model after the bacterial counts were decreased from 109CFU×g-1 to 103CFU×g-1. Natural logarithm of μ (the relative inactivation rate) and M (time constant) were fitted with linear regression model. The kinetic models were validated at 59℃ and 64℃. [Results] We established one first-level model and one secondary-level model to predict the inactivation rate. In addition, we validated the accuracy and deviation of the models to guarantee their feasibility. [Conclusion] The models should be suitable for describing the survival of L. monocytogenes in ground beef at different temperatures, which are helpful for the control of the pathogens.