The U.S. Department of Agriculture said Tuesday it has confirmed the country's fourth case of mad cow disease, marking the first bovine spongiform encephalopathy infection since 2006, in a development that could affect Japan's decision on whether to ease its import restrictions on U.S. beef.
The USDA stressed human health was not at risk, as the infected animal, a dairy cow from Central California, was never intended to be slaughtered for human consumption.
"The carcass of the animal is being held under state authority at a rendering facility in California and will be destroyed," the department said in a statement, adding the infected cow "at no time presented a risk to the food supply or human health."