Kinetic parameter estimation in prepackaged foods subjected to dynamic thermal treatments

Consumer demand for higher quality processed foods provides an impetus for designing processes that are less detrimental to product quality, while maintaining adequate levels of security from food borne illness. Thermal process design requires knowledge kinetic parameters of food constituents that affect product safety and quality.;The purpose of this study was to develop a method for estimating product and process specific thermal kinetic parameters. The method, referred to as the Paired Equivalent Isothermal Exposures (PEIE) method, may be applied to products that heat non-uniformly under non-isothermal heating conditions. Such conditions are typical with thermally processed prepackaged foods.;The research was performed in four phases: (1) development of the PEIE method for the case of foods and/or samples that heat uniformly, (2) assessment of approaches to heat transfer simulation for foods that do not heat uniformly, (3) development of the PEIE method for the case of foods that do not heat uniformly and (4) demonstration of one potential application of the PEIE method involving hybrid irradiation/thermal process design.;The PEIE method was used to quantify the impact of irradiation pretreatment on the thermal sensitivity of Bacillus stearothermophilus (NCA 1518) spores in canned pea puree. Cans of inoculated puree were irradiated with x-rays at 0, 1.0 and 3.0 kGy at an electron linear accelerator facility prior to thermal treatment in a vertical still-cook retort. Enhanced thermal sensitivity was apparent from changes in Arrhenius kinetic parameters that described the rate of inactivation of the spores as a function of temperature. Mean rate constants, k...