Sensitization of Clostridium perfringens spores to heat by gamma radiation

Spores of Clostridium perfringens, type A, were given separate or sequential treatments of gamma radiation (0 to 0.7 Mrad) and/or high temperature (93 to 103 degrees C). Prior heating, sufficient to inactivate 40 to 99% of the viable spores, had no effect on the subsequent radiation inactivation rate. Prior irradiation had a sensitizing effect on subsequently heated spores. The degree of sensitization to heat, as measured by thermal inactivation rate, increased with increased radiation pretreatment dose.