THERMAL-PROCESS SIMULATIONS FOR SOUS VIDE PROCESSING OF FISH AND MEAT FOODS

A finite difference computer model, based on the numerical solution to a three-dimensional heat conduction equation with a finite surface convection (h), was used to simulate the time-temperature profiles of sous vide processed foods in rectangular, thin profile forms. The h values and the thermal conductivity (k) needed for the simulation were obtained from the literature. Thermal diffusivity (alpha) values were obtained from heat penetration tests involving the spaghetti with meat sauce (pH 5.0; a(w) 0.98) and rice with salmon (pH 7.0; a(w) 0.97) products. Pasteurization values and microbial count reductions (based on previous thermal kinetics data for Streptococcus faecium) under pasteurization conditions computed from the simulation were comparable to those determined experimentally. The validated computer model was used to develop typical sous vide pasteurization schedules for processing these products using various temperatures.