Radiation resistance of spores of some Clostridium perfringens strains

Clostridium perfringens spores (eight strains) were irradiated in a model system with 60Co gamma rays at -30 C. The quantal response data obtained were analyzed with extreme value statistics. It was found (at the 95% confidence level) that all eight strains followed the same rate of death and that this rate was probably (at the 95% level) not exponential. The statistics did not exclude, however, a normal, lognormal, Weibull, or related rate of spore kill. A more definitive study would be required to distinguish between the latter distributions.