Next, we evaluated whether the inactivation strategy developed above for spores in suspension could be utilized for inactivation of spores attached to food contact surface materials typically used in food industries. SS was selected as a model of food contact surfaces
due to its widely use in both food industries and domestic kitchens (Holah and Thorpe, 1990;Liu et al., 2006). After inoculating the SS chip with spores (approximately 10กำลังเเปด CFU/ml) cocktail from three C. perfringensFP isolates, the initial adhesion of spores on chip was approximately 5 log CFU/chip (Count A,Table 3). Increasing the concentration of spores and drying period during adhesion did not increase spores adherence to SS chips (data not shown). This suggests that the spore population of 10 กำลังแปด CFU/ml was already excessive for bacterial adhesion. Because the suspension tests indicated that inducing germination at 40 C with AK before inactivation gave a greater spore-killing effect than at RT for both FP and NFB isolates,
the surface decontamination experiments were conducted only with spores germinated at 40C.