Concerns in South Korea over the safety of American beef, following the first documented case of mad cow disease since 2006, caused two South Korean retailers to halt sales of the meat.  One retailer, Home Plus, later recanted is suspicion after reports of increased government inspections were released, according to the Associated Press.

A representative from South Korea’s third-most popular chain, Lottemart, was quoted in an article in CNN.com as saying:

"Currently, the sale of U.S. beef is temporarily suspended to ease our customers from anxiety." 

From the Associated Press:

"I won't eat meat from the countries where mad cow disease was found," said Kim Woo-sig, a self employed 47-year-old.  Home Plus said its decision to resume sales of U.S. beef does not mean it will purchase additional meat from the U.S.”

The Associated Press reports that White House spokesman Jay Carney repeated earlier statements about the health of the country's cattle industry:

"American beef and dairy are safe and the Agriculture Department is obviously very focused on looking into this matter" 

South Korea comes in as one of the world’s top importers of American beef and veal, fourth after Japan, Mexico, and Canada, all of which have pledged to continue beef imports after reassurance from the U.S. government that the infected cow posed no threat to the food supply chain.

The California dairy cow infected with bovine spongiform encephalopathy is only the fourth cow in American to have been identified as having the disease.  BSE is commonly spread through meat and bones from cattle carcasses that is reprocessed into meal and used as feed, but U.S. Agriculture Secretary Tom Vilsack called this an “atypical” case in an article on CNN.com:

"It's not connected in any way, shape or form to feed. ... A very rare circumstance and situation.  It can just sort of come up and pop up -- sometimes it's genetic."

BSE, caused by a pathogen that invades healthy tissue proteins and uses them as transmissive templates for more degenerated protein, can incubate in cattle for up to 8 years, making diagnosis of the disease difficult.  Faulty proteins build up in nervous tissue of the brain and spinal cord, and infected animals eventually display aggressive behavior, poor muscle control, weight loss, and reduced milk production.

Bovine spongiform encephalopathy is known for its high resistance to heat in cooking, and can be transmitted to humans through the brain, spinal cord, or digestive tract tissue of contaminated catttle.  It is believed to behind the incurable and fatal Creutzfeldt-Jakob disease in humans, in which brain tissue degenerates into a hole-filled and spongy texture. 

In 1999 an epidemic of Creutzfeld-Jakob disease killed 166 people in the United Kingdom. CNN.com reports:

“Last year, 29 cases of BSE were reported worldwide, down 99% from the peak of 37,311 cases in 1992.”