PRESSURE-INDUCED GERMINATION AND INACTIVATION OF BACILLUS-SUBTILIS SPORES

The ratio between dormant and germinated bacterial spores in an aqueous solution could be estimated using a temperature treatment at 80-degrees-C. Using this concept, an optimized pretreatment at pressures of 600 to 1500 bar was developed. The result was an almost quantitative germination of the former dormant spores. Subsequent inactivation was the same whether 80-degrees-C or 3000 bar was used and in both cases an identical number of remaining viable spores was detected. The pressure inactivation of bacterial spores was studied in the range from 600 to 6000 bar at temperatures of 40 and 50-degrees-C At 40-degrees-C the number of germs could be reduced by the factor of 10(6) after 210 min of pretratment at 600 bar and following inactivation at 5000 bar for some minutes. Raising the temperature to 50-degrees-C, an alternating pressurization at 600 and 5000 bar in intervals of 30 min led to the complete inactivation of spores after an overall time of 180 min.