The study of heat penetration into foods is of great importance for a food engineer or scientist because heat processing is the most common technique used for food preservation. Strict regulations and procedures are established by government agencies for the thermal processing of low-acid canned foods because there is widespread public health concern about the anaerobic Clostridium botulinum, a spore-forming microorganism that produces a toxin deadly to humans, even in very small amounts. Two different methods for conventional thermal processing are known: aseptic processing, and canning processing. Although the laboratory experiment will focus on the canning process, the concepts applied are also applicable to aseptic processing. To evaluate the effectiveness of a thermal process, it is necessary to know the thermal history of the product and the thermal resistance of the microorganism of concern. During a typical retort operation, the following three defined stages can be distinguished: venting and come-up time; cooking or processing cycle; and cooling cycle.