More US mad cow mistakes raise credibility concerns

The USDA is now investigating a possible third U.S. case of mad cow disease, or bovine spongiform encephalopathy (BSE), in an animal at least 12 years old.
A brain sample from the suspect cow was taken by a local veterinarian in April but was not tested by the USDA until last week. That delay was because the veterinarian "simply forgot" to submit it, the USDA said.
The sample was frozen, a violation of USDA guidelines, and the veterinarian also mistakenly used a preservative that limits the type of mad cow tests that can now be conducted.