Health officials have traced an E. coli outbreak to lettuce at K-F-C and Taco Bell locations. Twenty people in all have become sick in Nova Scotia, New Brunswick and Ontario. There were four cases in Ontario. A Nova Scotia health official says investigators believe that lettuce distributed to the fast-food outlets is to blame. He says lettuce has a short shelf life and no new cases have been reported in more than a week. Symptoms of the gastro-intestinal illness include severe cramps, bloody diarrhea and vomiting.