This Tuesday, April 24, 2012, photo shows an exterior view of Baker Commodities transfer station, where a cow with mad cow disease was discovered, in Hanford, Calif. The first new case of mad cow disease in the U.S. since 2006 has been discovered in a dairy cow in California, but health authorities said Tuesday the animal never was a threat to the nation's food supply. The infected cow, the fourth ever discovered in the U.S., was found as part of an Agriculture Department surveillance program that tests about 40,000 cows a year for the fatal brain disease. (AP Photo/ Gosia Wozniacka).