The first U.S. case of mad cow disease in six years sparked fears of illness that prompted at least one major South Korean retailer to suspend the sale of American beef.

However, public health officials said the risk for disease for Americans is extremely low given that the affected dairy cow in central California was not part of the human food chain and was not exposed to bovine spongiform encephalopathy (BSE) through animal feed.

"It was never presented for slaughter for human consumption, so at no time presented a risk to the food supply or human health," said John Clifford, the Agriculture Department's chief veterinarian.

Read the full story: "S. Korea curbs U.S. beef sales after confirmation of mad cow disease"