Survival, injury, and virulence of freeze-stressed plasmid-bearing virulent Yersinia enterocolitica in ground pork.
The effect of freezing at -20 degrees C on survival, injury, stability of the virulence plasmid, and expression of virulence-associated determinants of Yersinia enterocolitica (YEP(+)) in ground pork was assessed. The viable counts on nonselective and selective media after 12 weeks of freezing were similar to counts obtained before freezing, indicating that the YEP(+) strain survived the freezing process. There was no evidence of freeze-stress injury. Results of a PCR assay targeting plasmid-associated virF gene and virulence determinants indicate that YEP(+) subjected to freezing are potentially capable of causing food-borne illness and freezing is not a substitute for safe handling and proper cooking of pork.
Bhaduri
Saumya
S
MFS Research Unit, Eastern Regional Research Center, U.S. Department of Agriculture, Agricultural Research Service, Wyndmoor, Pennsylvania 19038, USA. sbhaduri@errc.ars.usda.gov
D000818:Animals; D015169:Colony Count, Microbial; D005615:Freezing; D008460:Meat / Q000382:microbiology*; D010957:Plasmids / Q000235:genetics*; D013552:Swine; D015008:Yersinia enterocolitica / Q000235:genetics / Q000472:pathogenicity* / Q000502:physiology*