More than 100 people attending the Food Safety Summit in Maryland last month were sickened by what investigators think may be food poisoning. There were no hospitalizations reported and the vast majority of those affected only suffered from diarrhea.

Health investigators are still trying to trace where the infection started and have not ruled out the possibility that the outbreak was passed from person to person. However, it seems most likely that the problem occurred from food served at the conference, which was attended by over 1,300 food safety experts.

Officials with the Maryland Department of Health and Mental Hygiene and the Baltimore City Health Department have so far questioned about 400 of the attendees but it is too early to determine the cause of the sickness, Reuters reported. Complaints of nausea and diarrhea started about a week after the conference, which prompted an inspection of the convention center and the catering company that delivered the food for the event. A violation for condensation dripping from an ice machine was issued, a city health department spokesman told NBC News.

The conference took place between April 8 and April 10 and was attended by experts with the U.S. Food and Drug Administration, the Centers for Disease Control and Prevention and representatives of companies including McDonald's and Tyson Foods.