The effects of gamma-radiation and heat on the germination of spores of Clostridium botulinum type E.

Abstract

Spores of Clostridium botulinum type E were exposed either to various doses of γ-rays or to lethal and sublethal temperatures, then the effects on germination were studied by using the following two defined media: (A) L-alanine + glucose + bicarbonate and (B) L-alanine + lactate +bicarbonate. An increased inhibition of germination either by raising the temperature or by increasing the dose level was observed when medium A was used. On the other hand, activation by heat, but no activation by γ-radiation were observed when medium B was used. The heat activation was unaffected by additional pre or post-irradiation. The amount of DPA released from spores by treatment with heat increased progressively with elevating temperatures, whereas no detectable amount of DPA was released by γ -irradiation at any of the sublethal doses applied. From the results that spores of Clostridium botulinum type E can be activated by heat but not by γ-radiation, could be explained on the basis of the difference in the manner of breaking dormancy between two agents.