Effect of temperature on the inactivation of Bacillus stearothermophilus IFO12550 spores by low hydrostatic pressure treatment

The effect of heat treatment on the inactivation of Bacillus stearothermophilus IFO12550 spores by low hydrostatic pressure (LHP: 10-100 MPa) was studied. There were optimum temperatures in the inactivation of spores at 10, 20, 30 and 40 MPa. On the other hand, there was no optimum temperature in spore inactivation at 50, 60 and 100 MPa, and inactivation was dependent on the treatment temperature. The PD value at 30 MPa was at a minimum at 75°C compared with at other temperatures. Thus, hydrostatic pressure below 40 MPa was effective in inactivating the bacterial spores by LHP treatment at optimum temperatures.