THE RETARDATION OF THERMAL DISINFECTION OF BACILLUS SUBTILIS SPORES BY HYDROSTATIC PRESSURE

Abstract

At 25[degree]C, spores of B. subtilis suspended in buffered salt soln., pH 7, die slowly at normal pressure and somewhat faster under 600 atmospheres of hydrostatic pressure. Short periods of compression have no appreciable effect on viability. The rapidity of decompression, or repeatedly subjecting to pressure for short periods of time, has no appreciable effect on viability. At 92.5[degree] or 93.6[degree]C, however, disinfection rapidly occurs after a pronounced lag, and the whole process is retarded by a hydrostatic pressure of 600 atm. In greatly diluted salt soln. at these temps. disinfection is faster and the lag less pronounced, but pressure retards the rate; and the shape of the curves relating number of survivors to time of exposure to heat is generally similar.