CHAPEL HILL, N.C. — More than 300 University of North Carolina at Chapel Hill students recently came down with the norovirus, better known as the stomach flu. Investigators with the Orange County Health Department now believe all the clues point to Lenoir, one of the campuses' main dining facilities.

Two weeks ago, dozens of students went to the campus health clinic complaining of nausea and diarrhea. When more students became sick, doctors knew they had a problem on their hands.

Investigators from the Orange County Health Department were brought in. Health officials had students fill out questionnaires to see if they could pinpoint a cause. Those surveys eventually led them to the dining facility.

Health officials said raw foods, like those found on salad bars, can be easily contaminated with the virus and the contamination could have happened before the food even arrived on the UNC campus.

Health investigators reviewed all procedures used by UNC Dining Services and found no problems with sanitation or the food-handling process.