MECHANISM OF INACTIVATION OF HEAT-TOLERANT SPORES OF BACILLUS-STEAROTHERMOPHILUS IFO-12550 BY RAPID DECOMPRESSION

The effect of three rapid decompression methods to clear the mechanism of inactivation of heat tolerant spores of Bacillus stearothermophilu s IFO 12550 was investigated. Pressurization of the spores at 200 MPa and 75 degrees C for 60 min caused a kill of 10(4) CFU/mL by the link- motion system but the nonrotational rod valve and E.G. seal methods ga ve a kill of about 10(3) CFU/mL, Sterilization was due to the physical breakdown of spore coat, and was induced by its physical permeability of water at high pressure and temperature, Rapid decompression by the link-motion system at 200 MPa decreased the D-value of the spores fro m 3000 min (100 degrees C, one atmosphere) to 6 min, 11 min, and 17 mi n at 95, 85, and 75 degrees C, respectively.