Background: October and November of 1999, two outbreaks of E. coli O157:H7 with indistinguishable pulsed field-gel electrophoresis (PFGE) patterns were identified. The first outbreak was in Idaho with a strong Epidemiological link with eating venison pepperoni, which possibly contained beef. The pepperoni isolate PFGE pattern was indistinguishable from the human cases. The second outbreak, involved CA, AZ and NV implicating hard shell beef tacos. No product was available for testing. An investigation was done on the beef to see if the two outbreaks were epidemiologically linked. Methods: A multistage investigation was done. First, from the restaurant chain, on whom supplied their precooked beef taco product. Second, from the supplier to determine where the raw beef product originated. Third, from the pepperoni processor, on their supplier of beef carcasses. Finally, we attempted to identify the farm-source of the beef. Results: Carcass beef from one slaughterhouse went to the pepperoni maker and to another slaughterhouse. The latter sends raw beef to the supplier of the taco meat filling. Processing dates of carcasses received by the pepperoni maker with the taco beef maker did not conclusively demonstrate a common source. Beef carcass records are not maintained between slaughter and processing, identifying the farm was impossible. Conclusion: One slaughterhouse may have supplied beef for the tacos and the pepperoni. However, due to the limitation inherent in the tracing of beef from processor to farm we can not conclusively implicate a common source. These findings argue for a tracking system that begins on the farm.
Learning Objectives: Recognize that pulse field gel electrophoresis (PFGE) patterns may match and appear to be similar, but not yield conclusive evidence of a link in foodborne illness outbreaks
Keywords: Food Safety, Epidemiology
Presenting author's disclosure statement:
Organization/institution whose products or services will be discussed: None
I do not have any significant financial interest/arrangement or affiliation with any organization/institution whose products or services are being discussed in this session.