(Reuters) - A U.S. food safety summit in Maryland earlier this month has become a cautionary tale after more than 100 attendees came down with suspected food poisoning. Most of those affected complained of diarrhea, the Maryland Department of Health and Mental Hygiene said in a statement. Local health officials have heard from about 400 of the 1,300 attendees and are at a loss as to the exact cause of their illness. The April 8-10 meeting at the Baltimore Convention Center included representatives from the U.S. Food and Drug Administration and the Centers for Disease Control and Prevention, and food...