The USDA confirmed Tuesday that it had located a case of mad cow disease in California.
Mad cow disease, or bovine spongiform encephalopathy, is a progressive neurological disease among cattle that is always fatal.
The USDA has begun to notify authorities at the World Organization for Animal Health as well as U.S. trading partners. According to John Clifford, the USDA’s chief veterinary officer, the finding should not affect the nation's beef exports.
"It was never presented for slaughter for human consumption, so at no time presented a risk to the food supply or human health," Clifford said. “Additionally, milk does not transmit BSE."
The case marks the fourth time mad cow disease has been discovered in the U.S. The first case was discovered in the U.S. in 2003. Subsequent cases turned up in 2005 and in 2006.
The carcass of the cow has been destroyed. The cow was not believed to have contracted the disease by eating contaminated food, the USDA added.