Model of the Inactivation of Bacterial Spores by Moist Heat and High Pressure

ABSTRACT: Formulae for the prediction of inactivation and accumulated lethality of bacterial spores under moist heat and high pressures were derived on the basis of classic thermodynamic and kinetics principles. The capability of the model to describe the inactivation of bacterial spores was verified using 2 independent data sets corresponding to Clostridium botulinum processed at 60°C to 75°C and Bacillus stearothermophilus processed at 92°C to 110°C. Both sets included pressures between 5 × 108 Pa and 7 × 108 Pa. The equation fit explained more than 86% of the variation of the rate constant data. The developed equations establish a strong foundation on which to compare high-pressure processing treatments of different systems. This is especially useful because most systems have different transient temperature-pressure conditions.