The behavior of these microorganisms in foods during the industrial processing steps and the storage stages is afterward very variable and the diversity of their heat resistance and growth characteristics has been extensively studied. As mentioned above, chromosomal cpe-harboring strains of C. perfringens were shown more heat resistant than plasmid cpe harboring isolates. For instance, Sarker et al. (2000) reported a mean D-value at 55 C of 13.1 min for vegetative cells of isolates carrying a chromosomal gene against a mean value of 6.7 min for isolates carrying a plasmid gene. This difference was even more pronounced for spores with a mean D-value at 100 C of 60 min for chromosomal cpe-harboring
isolates against a mean D-value of 1.0 min for plasmid cpeharboring
isolates.