Heat resistance of native and demineralized spores of Bacillus subtilis sporulated at different temperatures

Demineralization reduced heat resistance of B. subtilis spores, hut the pat tern and magnitude of the reduction depended on sporulation temperature and on heating menstruum pH. The differences in heat resistance of native spor es caused by sporulation temperature almost disappeared after demineralizat ion. Demineralized spores were still susceptible to the heat-sensitizing ef fect of acidic pH.