A story by Reed Cowan of ABC4 finally named Wendy’s as the source that exposed 100 people to E. Coli at convention. From the article:

An E. Coli outbreak in North Ogden has health department officials pointing fingers at a Wendy’s fast-food restaurant.
It happened in June when some three hundred educators were attending a conference at a junior high in Harrisville. One of the days Wendy’s catered the event. The health department investigation concluded that iceberg lettuce from Wendy’s was the common denominator in three confirmed cases and a number of other unconfirmed cases.
A Wendy’s representative told ABC 4 News, “We are very saddened that apparently people got sick eating the lettuce from one of our restaurants. When situations arise we will always do the right thing for our customers.”
Gwen Hadley with the Weber Morgan Health Department told ABC 4 News one of the victims became so ill she couldn’t speak. However, officials say the illnesses and infections have run their course and there is no risk of further infection.