The source of the E. coli O157:H7 that contaminated specialty hamburgers made by Cardinal Meat Specialists Limited in Ontario is going to remain a mystery, the Canadian Food Inspection Agency (CFIA) acknowledged Monday. CFIA’s official investigation into the foreign and domestic beef used by Cardinal Meat, along with all the spices used as ingredients in the hamburgers has now ended without producing any evidence to identify a source of the contamination. The beef products from the Cardinal Meat Specialists’ plant at Brampton, Ontario that were recalled for E. coli O157:H7 contamination included: Butcher’s Choice Garlic Peppercorn, Butcher’s Choice Hickory Barbecue, and Cardinal Select Prime Rib Beef burgers. Canadian health officials earlier connected the genetic fingerprint of the bacteria found on samples one day’s production from the Cardinal plant with three E. coli illnesses in Ontario and two in Alberta.  In a statement, CFIA said investigators pursued all avenues of inquiry, including:

  • Assessing production, inspection and testing records;
  • Reviewing plant food safety procedures; and
  • Conducting additional testing on burger ingredients.

CFIA on Dec. 21 eliminated foreign beef sources, in Australia and New Zealand, as the cause of contaminate. There haven’t been any reported cases of illness with the same E. coli O157:H7 genetic fingerprint outside of Canada. The CFIA has now confirmed that all available domestic beef ingredient products have also tested negative for E. coli O157:H7. As all lines of inquiry have been exhausted, CFIA said its investigation will not progress further. A detailed report of the investigation will be posted on the CFIA’s website in the coming weeks. The Cardinal beef products were recalled between Dec. 12 and Dec. 15, 2012. CFIA said it will continue to work with local public health authorities to monitor any further illnesses that might be reported