The United States Department of Agriculture has confirmed that a cow with mad-cow disease has been found in California, the fourth such incidence in the U.S. since 2003.

According to John Clifford, the USDA's chief veterinarian, the dairy cow was found in a rendering facility in central California.

Clifford said the cow did not enter the food chain and will be destroyed.

"The carcass of the animal is being held under State authority at a rendering facility in California and will be destroyed," Clifford says. "It was never presented for slaughter for human consumption, so at no time presented a risk to the food supply or human health. Additionally, milk does not transmit [bovine spongiform encephalopathy]."

The USDA tested samples of the cow at a laboratory in Ames, Iowa, using both immunohistochemistry and western blot tests.

Last year there were 29 cases of bovine spongiform encephalopathy, more commonly referred to as mad-cow disease.

"USDA remains confident in the health of the national herd and the safety of beef and dairy products," Clifford says.

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