Thermobacteriology: principles and application for dairy foods

Abstract Heat treatment encompasses several processes that aim to inactivate microorganisms in the dairy industry. The control of time and temperature are critical factors of thermal processing. Also, the physiological responses of microorganisms may be neglected, especially their thermal resistance. Thus the efficiency of thermal processing does not depend only on the time/temperature binomial, but it is also related to the thermal resistance of microorganisms. Several mathematical models can be used to describe the microorganism inactivation exposed to thermal processes. Usually, thermal processes, such as pasteurization, induce the microbial inactivation at a logarithmic rate. In other words, regardless of the population size present in the food matrix, a constant proportion of the microorganism population is inactivated during a determined time interval when exposed to temperature conditions beyond their tolerance range. Furthermore, some properties of food, such as size, shape, composition, and viscosity, may influence product heating in the thermal process.