The Bush administration banned all beef imports from Canada on Tuesday, shortly after officials there announced that an 8-year-old cow had been confirmed to have had mad cow disease when it was slaughtered. The disease's incubation period can be as long as eight years; so it was unclear when the animal was infected.
The administration said it would send veterinarians and others to help the Canadians investigate, and should the case prove to be an isolated incident, the import ban could be abandoned fairly soon.
"We're being very vigilant," said FDA Deputy Commissioner Les Crawford. But, "I don't think it poses, at this point, a public health threat for the U.S."
Agriculture Secretary Ann Veneman was more pointed: "At this time we see no reason for any consumer to be concerned about the safety of the food supply, and in fact I intend to eat a steak tonight," she said on CNN.
South Korea on Wednesday banned all beef and cow part imports from Canada, the agriculture ministry said. The same day, Japan imposed a temporary ban on imports of Canadian beef products.
The infected cow from a farm in northern Alberta was slaughtered Jan. 31 because it was believed to have had pneumonia, Canadian Agriculture Minister Lyle Vanclief said. Tests in England confirmed it was infected with bovine spongiform encephalopathy, or BSE, known more commonly as mad cow disease.
Canadian officials said the cow's herd would be slaughtered and the farm quarantined. "A trace on the animal is being done," Vanclief said. "The animal did not go into the food chain."
"We will make all resources available," Veneman said of U.S. assistance. "We will do everything we can to help them track back this particular animal and to try to make a determination as to what happened here."
Mad cow disease has never been found in U.S. cattle, despite intensive testing for it. The U.S. government routinely seals the border against imports of meat and cattle from countries where mad cow disease is found, because the cattle disease is linked to a brain-destroying human illness called new variant Creutzfeldt-Jacob disease. The human illness is believed to spread by eating brain or nerve tissue from infected animals.
Mad cow disease sprang up in Britain in 1986 and later spread to countries in Europe and Asia. It is thought to have spread through cow feed that included protein and bone meal from sheep or other mammals.
The FDA outlawed feeding mammalian meat and bone meal to cattle, sheep and goats in 1997, a rule considered the nation's main defense against mad cow disease. Canada has a similar ban.
There has been one previous known North American case of mad cow disease — in 1993, an animal in Canada that was imported from Britain. The animal's herd was destroyed and the disease did not spread.
Canada is the top foreign supplier of live cattle to the United States, exporting 1.7 million head last year, or 75 percent of U.S. imports. About 7 percent of beef consumed by Americans is from Canada, said Michelle Peterson, spokeswoman for the National Cattleman's Beef Association, which represents U.S. beef producers.
U.S. companies sought to reassure Americans about the safety of their beef after Canada's announcement, which triggered a sharp drop in stocks of big U.S. hamburger chains.
"McDonald's worldwide has the highest beef safety standards and will continue to strictly enforce them," the Oak Brook, Illinois, company said. The company said it does not import beef from Canada.
Outback Steakhouse said its restaurants serve only USDA top choice or prime U.S. Midwestern grain-fed beef.