A defunct Canadian meatpacker is "a likely source" of beef that caused an outbreak of food-borne illnesses in the United States and Canada, the U.S. meat safety agency said on Friday.

Nearly 100 illnesses have been reported due to the E. coli O157:H7 bacteria in the two nations. The U.S. Food Safety and Inspection Service said a comparison of "DNA fingerprints" of beef samples pointed to Ranchers Beef Ltd, of Balzac, Alberta.

The Food Safety and Inspection Service directed U.S. food makers not to use boneless beef "trim" from Ranchers Beef and to hold all raw products made from it until both nations complete the investigation. FSIS delisted Ranchers Beef as an importer on October 20.

In a statement, U.S. Agriculture Undersecretary Richard Raymond said the Canadian Food Inspection Agency provided so-called PFGE patterns from Ranchers Beef products that "helped us determine a likely source of contaminated product which led to the September 29 Topps Meat expanded recall."

The E. coli O157:H7 bacteria can cause diarrhea and dehydration and can be deadly. Children, the elderly and people with poor immune systems are the most susceptible.

A Ranchers Beef spokesman was not immediately available for comment.

Topps Meat, the largest U.S. maker of frozen beef patties, recalled 21.7 million pounds of beef. It announced on October 5 that is was going out of business because of the recall.

Ranchers Beef ceased operations on August 15. Some of its products remained in storage and were tested by CFIA as part of its investigation into illnesses in Canada.

The U.S. Center of Disease Control and Prevention said the PFGE patterns from Ranchers Beef matched those from patients who were ill and from beef samples taken by New York state officials, said FSIS.

Some 45 cases of illness caused by E. coli were reported in five Canadian provinces from July to September, including one death, said the CFIA in a statement. It said genetic testing found "the same unique E. coli pattern" in beef from an unnamed meat facility in Alberta that is "currently not operating."

"All remaining product is under detention," said the CFIA.

As of Friday, the CDC reported 40 illnesses under investigation in eight U.S. states.