APPLICATION OF HIGH-PRESSURE FOR SPORE INACTIVATION AND PROTEIN DENATURATION

Our objective was to develop a method of sterilizing Bacillus stearothermophilus spores with minimal heating. Inactivation was achieved by spore destruction through six cycles of oscillatory pressurization at 70 degrees C and 600 MPa, but inactivation was not complete within 60-min with continuous pressurization. Four pressurization cycles at 600 MPa and 5 min/cycle decreased the spore count from 10(6) to 10(2)/mL, and six cycles decreased the count from 10(6) to < 10(0). Spore inactivation was dependent on the adiabatic expansion velocity. On the other hand, protein denaturation by high pressures was due to phase changes of water under high pressure, and was not affected by adiabatic expansion velocity.