DISRUPTION OF MICROBIAL-CELLS BY THE FLASH DISCHARGE OF HIGH-PRESSURE CARBON-DIOXIDE

In order to develop a novel sterilization method for heat-sensitive materials, the disruption of microbial cells by the rapid release of gas pressure was examined under various conditions of pressure, temperature, treatment time and water content of the cells. Wet cells of baker's yeast were completely destroyed, after the microorganisms had been saturated with CO2 gas at 40 degrees C and 40 atm for more than 3 h when the pressure was suddenly discharged. On the other hand, dry cells were poorly killed even under the same experimental conditions. In particular, N-2, gas with low solubility in water had no effect on the survival ratio of the yeast. From these results, the death of microorganisms may be caused by mechanical breakage and/or physiological damage related to gas sorption and desorption by the cells.