There's an old joke in Britain that goes, I used to have mad cow disease but I'm alright noooooo! The old ones are the best. However, it is in California not Britain that the most recent infected cow has been discovered. If the British can teach America anything, it is that nothing causes a public outcry like a mad cow scare. Expect mass hysteria. On infected cow was found in central California, according to the USDA. This is the fourth case ever in the U.S., and the first since 2006. The most pertinent point is that the cow never entered the food supply. Of course, that won't stop the fear spreading like a bad rash. Following the news, McDonald's shares dropped 0.9%, while Wendy's shares fell 1%. It has yet to be confirmed f the decline has anything to do with the discovery, but if not it's a hell of a coincidence. The repercussions are being felt worldwide though. Two major South Korean retailers suspended sales of U.S. beef on Wednesday. Again, ask Britain and it will tell you that this sort of thing doesn't just go away overnight. Tell people that food is dangerous and they will steer clear for a long time. “We stopped sales from today,” said Chung Won-hun, a Lotte Mart spokesman, as quoted by the AP. “Not that there were any quality issues in the meat but because consumers were worried.” Of course they are. Mad Cow disease, or bovine Spongiform Encephalopathy, causes a deadly human brain disease if you eat diseased beef. The Agriculture Department studied 40,000 cows, found one infected beast, and took it out of the food chain. Solving the problem is never that simple though. The problem is in the public's collective mind now (although, thankfully, not literally). Still, rest assured that the infected cow is out of the way, so says the USDA in a statement. "The carcass of the animal is being held under State authority at a rendering facility in California and will be destroyed. 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 BSE." Additionally, it should set minds at ease to know that the infected cow did not contract the disease from feed. Rather, it was simply a mutation that occurs from time to time. Wait - hold the phone? This can just happen randomly, at any time to any cow? Those in the know correctly say that random mutations can happen in nature all the time, so fear not. Thankfully, those good people at the USDA had their eyes on the ball this time. Your Big Mac is (kinda) safe, for now.