TRENTON — The number of reported E. coli cases being investigated in New Jersey was up to eight on Friday.

Five of those people hospitalized have been discharged.

Investigators from the state Department of Health continued talking to those affected and trying to track their eating history in the days leading to when they became ill, according to state Epidemiologist Tina Tan.

While a Warren County health official has said that a Panera Bread eatery was being eyed as a potential source of the illness, Dr. Tan said the association between the eight people "may be broader" than a single restaurant chain.

"It can be very difficult to determine where someone got sick. Individuals could have eaten a number of meals in a number of places before becoming ill. They could have eaten at several restaurants, at home or eaten food purchased at a supermarket," Tan said. "Sometimes the food source associated with illness is never determined. That’s why we conduct many interviews with sick individuals to get food history data."

Tan said anyone who had gotten sick after eating to see a doctor if they have severe stomach cramps, diarrhea and vomiting.

There are four cases reported in Hunterdon County, two in Somerset and one each in Middlesex and Somerset counties.

"Some people may have a mild fever. Most people get better within five to seven days," Tan said.

The health department's investigation has two parts: Determining if the strains of E. coli match in those affected and determining the common food source that made people sick.

Contact reporter Dan Alexander at Dan.Alexander@townsquaremedia.com or via Twitter @DanAlexanderNJ