MODELING THE GROWTH AND DEATH OF BACTERIA IN INTERMEDIATE MOISTURE FOODS
A quasi-chemical model for the growth and death of bacteria was developed that accounts for the associated population-time profile and for the effects of water activity, pH, and temperature on the dynamics. The model translates the phases of the microbial life cycle into a kinetics mechanism consisting of sequential steps that depicts the interaction among reactive cells and a proposed antagonist, including their ultimate fate. The introduction of an antagonistic metabolite into the model is an important step in making the model conform to the experimental data. The combined population of three strains of Staphylococcus aureus was assessed over time in a ground bread substrate under different conditions to test the model. The rate constants associated with this model not only predict the dynamics, but also provide a fundamental basis for the observed behavior of the combined growth and death. Relationships between the rate constants in the model and the environmental parameters can predict a no-growth set of conditions.
Feeherry, F.E., Ross, E.W. and Taub, I.A. (2001). MODELING THE GROWTH AND DEATH OF BACTERIA IN INTERMEDIATE MOISTURE FOODS. Acta Hortic. 566, 123-128
Staphylococcus aureus, shelf-stable sandwiches, water activity, pH, temperature, mathematical modeling, antagonistic metabolite