An E. coli outbreak in Orange County has been traced to a restaurant, health officials said Monday.

The seven people who tested positive for the dangerous bacterium dined at the same restaurant in Lake Forest, six of them on March 23 or March 24, said Howard Sutter, spokesman for the county’s Health Care Agency. The seventh could not confirm an exact date.  Authorities have yet to determine the source.

The restaurant was allowed to remain open after health inspectors concluded its food and conditions were safe, Sutter said.  The seven cases were reported to county authorities in recent days. Three of those sickened were hospitalized, although their symptoms were not considered life threatening.