Lethality of thermal processes for food in anomalous-shaped plastic containers

Abstract A numerical simulation was performed to obtain the temperature distribution in a bowl-shaped plastic container with a metal lid. The boundary conditions included the first and thirk kinds, which were applied to the lid and the plastic parts, respectively. Due to the curvilinear boundary, a finite volume numerical method was used to calculate the nodal temperature, which was verified experimentally. The location of the lowest temperature (cold point) during heating was found by temperature interpolation and rearrangement of nodal points. It was found that the cold point of the bowl-shaped container, using a circulating superheated water-type retort, was located at 0·46 H on the rotating axis above the bottom. However, the lowest calculated total lethality, when including the cooling phase, was at 0·4 H and was 1% to 2% less than the lethality of the cold point (the lowest temperature in the heating phase).