3.2. Inducing germination and inactivation of C. perfringens spores
in suspension
It has long been recognized that spores loss their resistance
immediately upon germination (Hornstra et al., 2007). Therefore,
we initially assessed the working hypothesis that stimulating spore
germination can improve subsequent inactivation of germinated
spores by commonly used disinfectants for food contact surfaces.
Our results showed that the spore populations did not significantly
change after germination with buffer or AK for 30 min at RT or 40 C
(p > 0.05) as compared to the number of heat-activated spore
inocula implying that Na2HPO4 buffer and AK did not inactivate
spores of C. perfringens during germination induction (data not
shown). Therefore, the population of germination-induced cells
was referred as 0 min treatment count in all experiments.
Ethanol and Quats had no effect on dormant spores of
C. perfringens FP strain SM101 and NFB strain NB16 at both 40 C and
RT (p > 0.05) (Figs. 2A and B and 3A and B). However, germination of
SM101 and NB16 spores with AK at 40 C followed by ethanol (70%)
treatment resulted in reduction of 2.14 and 0.72 log CFU/ml,
respectively (Fig. 2A and B). While RT-germination led to a signifi-
cant (p < 0.05) killing of SM101 spores with ethanol, this effect was
not observed with NB16 spores, as they were unable to germinate
with AK at RT (Fig. 2B). Extending treatment time up to 15 min did