ABSTRACT
The definition of commercial sterility makes clear that a commercially sterile food may contain viable microorganisms, provided they are not capable of multiplying in the product at room or ambient temperature. The dimensioning of thermal processes, that is, the amount of heat that must be applied, depends on the heat resistance of the microorganisms capable of multiplying under nonrefrigerated condition. Two parameters are used to evaluate the heat resistance of microorganisms: the decimal reduction time, which is determined based on the survival curve, and the temperature coefficient, which is determined through the thermal destruction curve. In the destruction of microorganisms exposed to a constant lethal temperature, the reduction of the number of viable cells with time occurs at an exponential rate. Bacterial spores are different from heat-resistant mold spores in that they are not structures of reproduction, but rather structures of resistance. The heat resistance of bacterial spores varies with the species.
