Non-thermal Inactivation of Bacillus Spores by Pressure-holding
Access this Article
Search this Article
<I>Bacillus subtilis</I> spores were pressurized at 60MPa at 40°C for 0∼24 hours in phosphate buffer or GAM broth. After 24 hours, viable counts and spore counts decreased by about 5 log cycles in the broth and by only 1.6 log cycles in the phosphate buffer. Most of the spores in the broth changed from bright to dark after 4 hours, after which some of them began to bud, as observed by phase contrast microscopy. These results show that the spores germinated due to pressure and the presence of germination-inducing components in the broth, and that the germinated spores were then inactivated before changing into vegetative cells. We conclude that it is possible to inactivate <I>B. subtilis</I> spores by pressure-holding in non-thermal conditions. The same phenomenon was observed for <I>B. licheniformis, B. cereus</I> and <I>B. coagulans</I>, but the viable counts for these bacilli did not decrease as much as that of <I>B. subtilis</I>.
- Food Science and Technology International, Tokyo
Food Science and Technology International, Tokyo 11(3), 324-327, 2005-11-01
Japanese Society for Food Science and Technology