HARRISBURG, Pa. (AP) — While investigators work to pinpoint the cause of a western Pennsylvania hepatitis A outbreak that has killed three people and sickened more than 490, some food safety experts say green onions are particularly hard to keep clean. Luke LaBorde, assistant professor of food science at Penn State University, said Friday that the way green onions are grown and eaten, even the structure of the onion itself, can make them particularly likely to transmit diseases like hepatitis A.A study by the U.S. Food and Drug Administration found that green onions were more likely to be contaminated with...