Abstract
The combined effect of mild heating and pressurization on germination and inactivation of Bacillus subtilis spores was investigated. The spore count decreased remarkably at 60°C+80MPa in glucose broth as opposed to phosphate buffer. These results suggested that the spores germinated due to pressure and germination-inducing components in the glucose broth, and that the germinated spores were then inactivated by mild heating. The induction of germination started at 10MPa at 40°C or 20MPa at 60°C with the number of spores decreasing by two log-cycles in one hour. The relationship between the logarithm of spore number and pressure became linear in the pressure range of 50-300MPa. The germination ratio was 0.95log-cycles 100MPa at 40°C or 0.82log-cycles/100MPa at 60°C for half an hour in glucose broth.
