FIG. 1.

Thermal death curves at low temperatures for vegetative cells of NCTC10239, a type A isolate carrying a chromosomal cpe gene, and isolate 458, a type A isolate carrying a plasmid cpe gene. Vegetative cultures of NCTC10239 or isolate 458 were incubated at 4°C (A) or −20°C (B) for different times, and then aliquots were removed and plated onto BHI agar to determine the number of viable bacteria per milliliter of culture. The data are the results of a representative experiment; similar results were obtained when the experiment was repeated.