THE LETHALITY‐FOURIER NUMBER METHOD: CONFIDENCE INTERVALS FOR CALCULATED LETHALITY AND MASS‐AVERAGE RETENTION OF CONDUCTION‐HEATING, CANNED FOODS

摘要

ABSTRACTThe accuracy associated with a calculated lethality or mass‐average retention is dependent on the accuracy of the variables needed for the calculation. This study was undertaken to determine the effect of biological variability in destruction rates of microorganisms and quality factors and in thermal diffusivity on accuracy of thermal process calculations. Estimates of the distributions of these biological parameters were used in a Monte Carlo procedure to generate distributions of calculated lethality and mass‐average retention. From these distributions, the error in thermal process calculations could be determined. Variation in parameters describing destruction rates and thermal diffusivity of the food can result in standard deviation for the F‐value of 10–15s of the F‐value at small Fourier numbers (dimensionless heating time). At larger Fourier numbers (≧0.7) the standard deviation is approximately 5–8. For mass‐average retention, the maximum standard deviation is a