Comparison of Formula Methods for Calculating Thermal Process Lethality

Abstract

ABSTRACT Accuracy of five formula methods for determining process lethality in conduction heating foods was examined. Finite‐difference simulation was used to generate temperature history curves for a range of cans and processing conditions. Delivered lethality was evaluated using the formula methods and compared to the lethality calculated using a numerical general method. Deviations exhibited trends related to container dimensions and unaccomplished temperature difference (g), the largest errors occurring when g was large and the height‐to‐diameter ratio was close to unity. Errors were mostly on the “safe” side, but the energy use implications could be significant for high retort temperature processes.