Model for Combined Effects of Temperature, pH and Water Activity on Thermal Inactivation of <i>Bacillus cereus</i> Spores

Abstract

ABSTRACT Initially, the effect of water activity (a w ) on heat resistance of Bacillus cereus spores (decimal reduction time) was investigated. A linear relationship was found between log D and 1‐a w . The combined effects of temperature (85‐105°C), pH (4.5‐6.5) and water activity (0.80‐1) were then studied. A four parameter model was fitted to the data. This model appeared to be parsimonious with each parameter having a biological significance. Interactions between factors were observed but they accounted for &lt;2.4% of the total variation and they were not taken into account by the model.