In this review, current methods used to evaluate the integrated impact of time and temperature upon preserving a food product by a heat treatment are considered. After identifying the basic premise any preservation scheme shall meet, the central role of a feasible description for the heat activation kinetics of microorganisms, their spores, and other quality attributes are stressed. Common concepts to quantify a thermal process are presented. Shortcomings of the prevalent evaluation methods are highlighted and attention is given to the development, restrictions, and possibilities of time-temperature-integrators as "new" evaluation tools to measure the impact of a "classical" in-pack heat treatment and more modern heating techniques such as continuous processing of solid/liquid mixtures on foods.
Optimal variable retort temperature profiles (VRT) for the sterilization of conduction heated foods were calculated using a quasi‐Newton multivariable optimization algorithm considering both the maximization of surface quality and the minimization of total process time. When the maximization of surface quality was the objective, an increase up to 20% in quality retention was predicted for optimal VRT profiles as compared to optimal constant retort temperature profiles (CRT). When considering the minimization of total process time, the use of VRT profiles allowed reduction in the total process time of up to 45% while still providing the same surface quality as optimal CRT. Since the results could not be generalized, it was concluded that optimal VRT profiles should be calculated on a case‐by‐case basis.
Kinetic data on thermal destruction of spoilage and quality factors coupled with the temperature history of a product during a heat sterilization cycle are the basic information needed for the evaluation and the design of thermal processes through a physical-mathematical approach. A critical review on the available physical-mathematical procedures used for thermal process calculations of in-container processed foods is presented. The origin and the limitations of each method are discussed. The equations associated with each method, for internal product temperature predictions, are explicitly given. The relative performance of selected methods under identical processing conditions is illustrated. Several problems associated with thermal process calculations are discussed.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.