Selected challenges to modeling the kinetics of microbial inactivation and chemical reactions during food preservation

In the past, kinetic modeling of microbial inactivation and growth, and of chemical degradation or synthesis reactions in foods, was handicapped by the absence of mathematical tools to handle nonlinearities. This created the need for linearized model equations, notably of microbial inactivation, on which sterility criteria are still based. Modern numerical methods and user-friendly computer software now enable not only to accelerate calculations but also to challenge old concepts and revise or replace traditional models based on them. methodological problems in new ways and to find solutions to more elaborate novel ones. This is demonstrated with selected examples that include fully stochastic microbial survival models that can account for nonlinear inactivation, injury, thermal activation, and even simultaneous growth and mortality, the theoretical possibility of absolute thermal death time existence, and more accurate estimation of the static kinetic parameters of chemical reactions and microbial inactivation at ultrahigh temperatures and in combined thermal and nonthermal preservation methods.