The Centers for Disease Control and Prevention estimates that every day, 200,000 Americans contract food poisoning. "Everyone in this country will have at least one incident of sickness this year attributable to a foodborne virus, bacteria, or toxin," Tierno says. Except that most of us won't know what hit us; we'll chalk up the usually mild symptoms--nausea, diarrhea, cramping--to "that stomach flu that's going around."