— Bacterial spores contained in sugarcane bagasse were subjected to various combinations of heat exposure and alkali concentration and the rate of destruction determined for each set of conditions. A series of survival, thermal death time and alkaline destruction curves revealed a different mode of death by heat exposure than alkali treatment. Addition of alkali into the heating menstruum caused the death rates of bacterial spores to be much greater than with heat alone at a given temperature. Exposure of the spores to a temperature of 75°C for 130 min was required to reduce the spore population by 90% with heat treatment alone. Incorporation of a 1% NaOH solution into the heating menstruum effected the same degree of destruction of the spores within a 2 min period at the same temperature. From a series of thermal destruction and alkaline destruction curves, an empirical equation expressing the relationship between the death rate of bacterial spores, and the intensity of temperature and the concentration of alkali was established. The equation reveals that the death rate of bacterial spores is affected in an exponential manner by temperature and in a direct relationship by alkali concentration. Using the equation, sterilization time for various combinations of temperature and alkali concentration was determined and the overall correlation index between the experimental data and computed value was 0.877.

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