"WASHINGTON - A field worker has unwashed hands. An animal squeezes through a small tear in a fence. Manure from a nearby hog farm trickles into an irrigation system.
Small mistakes like these are often difficult to identify as the sources of food-borne illnesses, a situation that has frustrated health authorities for years. The Food and Drug Administration and other agencies gather information about a contamination outbreak after people have already been sickened, and their investigations into what went wrong come well after the crucial evidence is gone..."