WHEN mad cow disease was discovered in Washington State recently, it made headlines for days and brought action from the federal government. Coupled with a number of E. coli scares, it caused some Americans to swear off hamburger. But most people don't seem to worry about what experts say is a petri dish for food-borne illness: the home kitchen. "Everybody is so acutely aware of mad cow disease," said Janet Anderson, a clinical associate professor of nutrition and food sciences at Utah State University, "but people aren't aware of the fact that they don't even wash their hands when they...