Inactivation of Bacillus stearothermophilus spores during thermal processing

Abstract A combined effect of temperature, pH and NaCl concentration on thermal inactivation of Bacillus stearothermophilus ATCC 10149 spores was analysed. After pasteurisation at 80 °C for 10 min, the suspension of bacterial spores were sterilised at the temperature from 110 to 121 °C in a medium at different pH values (3–7) and various NaCl concentrations (0–6%). It was observed that the sterilisation temperature and pH of the sterilised medium as well as the concentration of sodium chloride, had a significant effect on spores activation and destruction. The activation of dormant bacterial spores in the medium at the parameters applied is possible already at the pasteurisation temperature.