Bacillus lethal temperature

The effects of EtO concentration and process temperature were widely studied. Ernst and Shull initially verified that the lethality kinetics of Bacillus subtilis var. niger spores is of zero order at high levels of EtO. With the EtO concentration reduction, the reaction becomes first order. Its sterilization curves at different temperatures show the required EtO concentration, and the duplication of the reaction rate of every 10°C. 

A new treatment process for food sterilization involving a combination of heat and sonication under pressure has been reported [44], This methodology was found to decrease the heat resistance of Staphylococcus aureus by 63% and Bacillus subtilis by 43% as compared to heat treatment alone. This effect decreased with increase in temperature towards boiling point due to the fact that cavitational collapse becomes much less violent at these temperatures. Under pressure the boiling point is raised and lethality of the microbes above boiling point is maintained with values 5 to 30 times greater than those achieved with heat treatment alone. Spores appeared to be most resistant and yeasts the most susceptible to this type of treatment. 

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