Mad Cow Missteps Shake Confidence in U.S. Beef
WASHINGTON, DC, July 28, 2005 (ENS) - The U.S. Department of Agriculture is investigating another "non-definitive” test result for mad cow disease
Mad Cow Missteps Shake Confidence in U.S. Beef
WASHINGTON, DC, July 28, 2005 (ENS) - The U.S. Department of Agriculture is investigating another "non-definitive” test result for mad cow disease, saying Wednesday that further testing is being done in the United States and England. The brain sample was taken by a private veterinarian in April, but not sent to the USDA until last week because, agriculture officials said, the veterinarian "forgot" to send it in for testing.
USDA Chief Veterinarian John Clifford told reporters that the animal did not enter the animal feed or human food supply. He said the animal appears to have been born in the United States.
The sample in question was taken from a cow that was at least 12 years of age and experienced complications during calving. The cow's age is important because it was born before 1997 when restrictions were placed on giving cattle feed containing the nervous system tissue of other cattle.
The BSE infection is caused by misfolded proteins called prions, found in nervous system tissues such as brains and spinal cords. Mad cow disease spreads from one animal to another by consumption of feed that has been contaminated by these prions.
While it is always fatal, BSE can take years to develop, so young animals are considered safer for human food than older animals. The human form of the disease can be transmitted if a human being eats BSE infected meat.
The private veterinarian treated the sample with a preservative, which readies it for testing using the immunohistochemistry (IHC) test - an internationally recognized confirmatory test for BSE. Neither the rapid screening test nor the Western blot confirmatory test can be conducted on a sample that has been preserved, said Clifford.
While Western Blot or rapid screening tests are not possible on the preserved sample, an immunohistochemistry (IHC) test has been run, though the result was not conclusive.
The IHC will be repeated at the National Veterinary Services Laboratory in Ames, Iowa and the World Reference Laboratory at Weybridge, England. Results are expected next week.
The rules governing chemical preservation of samples were changed in June when another inconclusive sample of a Texas animal turned out to be positive when tested with all three procedures.
The American Meat Institute (AMI) said that whatever the result, consumers and trading partners should not be concerned because "beef is safe from BSE, and even if the test ultimately confirms positive, the safety of the U.S. beef supply is unchanged."
"The beef we eat, like steaks, roasts and ground beef, is safe. These products have never been associated with a BSE-related human illness,” said AMI Foundation President James Hodges.
“People in Europe who became ill likely consumed brains or other infected tissues early in the BSE epidemic because the human health risk was not recognized,” Hodges said of the 150 people who have died from the human form of BSE, known as variant Creutzfeldt-Jakob Disease. “By contrast, these parts are removed in the U.S. and do not enter the food supply.”
Hodges stressed that the age of the animal indicates that if it is indeed positive for BSE, it was likely expose