Increasing the temperature to 90 C for 10 min produced no further effect on spore inactivation. However, when AK-induced germinated spores were treated at 90 C for 20 min, the spore inactivation increased to w5.3 DR (Fig. 3). These results indicate that at 55 C, 50 mM AK induces germination of spores which then can be inactivated by a subsequent heat treatment.