Evaluation of the Efficiency of a Congo-Red Uptake Technique for Detection and Isolation of Plasmid-Bearing (Pyv) Yersinia pestis KIM5 in Retail Raw Ground Beef and Pork

Saumya Bhaduri, James L Smith

Abstract

Knowledge of the presence of Yersinia pestis in food may be useful in the event that Y. pestis is used in a bioterrorism attack in the food supply. However, there are no reports on the enrichment and detection of Y. pestis in food. Congo red-uptake (CR-uptake) associated with the virulence plasmid was used to identify Y. pestis inoculated at various levels into ground beef (RGB) and pork (RGP) in fresh, cold-stored, and freeze-stored conditions. Y. pestis KIM5 was detected in fresh and refrigerated-stored sterile and non-sterile RGB and RGP when inoculated at 108, 106 or 103 CFU/g, but was not detected at 102 or 101 CFU/g level of inoculum. In RGB and RGP freeze-stored Y. pestis for 6 days, was detected only when inoculated into the meats at 106 to 108 CFU/g. Thus, the CR-method is suitable for detection of moderate levels of Y. pestis contamination without enrichment. Furthermore, the method is suitable for the isolation of Y. pestis from ground meat.