WASHINGTON -- Federal officials raced on Wednesday to find out where a Washington state cow, apparently infected with mad cow disease, was born and may have been infected. Even as the investigation continued, officials sought to reassure Americans about the safety of the nation's food supply. That didn't stop several nations from banning U.S. beef, including Japan, Taiwan and Mexico, the three largest importers. Been awhile since this has popped up. USDA Investigates Mad Cow Case | 
