OTTAWA, Ontario – The Canadian Food Inspection Agency has ended its investigation into Cardinal Meat Specialists Ltd., saying the agency could not find the source of E. coli that contaminated hamburger products.

CFIA said the agency pursued three lines of inquiry related to the ingredients – spices, domestic beef ingredients, and international beef ingredients.

The agency's investigation also included:

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

“As reported on Dec. 21, spices tested negative for E. coli and were ruled out of the investigation,” CFIA said. “It was also determined that international ingredients had met all import certification and testing requirements. Furthermore, there are no reported cases of illness in those countries with the same E. coli O157:H7 genetic fingerprint.

“The CFIA has now confirmed that all available domestic beef ingredient products have tested negative for E. coli O157:H7.

“As all lines of inquiry have been exhausted, the CFIA's investigation will not progress further. A detailed report of the investigation will be posted on the CFIA’s website in the coming weeks,” the agency concluded.

CFIA said the agency will continue its investigation into domestic beef ingredients, noting that "a variety of sources of domestic beef ingredients were used in the production of the recalled burgers". All products associated with illnesses reported in Ontario and Alberta was recalled between Dec. 12 and Dec. 15, according to the agency.

"While the agency will continue to rigorously pursue all leads, it is possible the source may never be definitively identified," CFIA said.