Prediction of Microbial Death by Heat and Evaluation of the Heating Process

Abstract

There have been reported many mathematical models for thermal inactivation of microorganisms in food. The basic models are an inactivation-technology model using D value and a chemical reaction model using a first order reaction. The former model is easy to handle, but hard to express non-linear survivor curves. The latter has a potential to describe non-linear curves. There are also empirical models to describe sigmoidal survivor curves of microorganisms during the heating period. Recently the interests of food scientists have focused on predictive microbiology models. Two expert software programs, Food Micromodel and Pathogen Modeling Program, are now available. During the heating process of a food product, the temperature of it changes. The temperature history of a food product is necessary for estimation of thermal inactivation of contaminants in it. F value may not directly indicate the magnitude of thermal death, but it can be a measure of thermal inactivation for a heating process. Also, a simple simulation of thermal inactivation of a pathogen contaminating a hamburger pate on a heated plate was performed using the heat conduction equation. A systematic model for thermal inactivation of microorganisms in food products that predicts the optimized thermal process of the products will further need to food industry.