TRENTON — A county health official identified the restaurant chain being investigated in connection with six reported E. coli cases in four New Jersey counties.

The state Department of Health did not name the chain, but Sarah Perramant, public health epidemiologist in Warren County, told NJ.com the Panera Bread on Route 22 in Phillipsburg was the focus of the investigation.

The first case was reported on March 28, state Epidemiologist Dr. Tina Tan told New Jersey 101.5, and more cases were identified in Hunterdon, Middlesex, Somerset, and Warren counties.

Perramant has not yet returned a message.

Tan said the cases may be connected to different locations of a restaurant chain, but would not name the chain until an investigation could make a stronger connection. The department is in the process of gathering food history data of those affected because it can be very difficult to determine where someone got sick.

"They could have eaten at several restaurants, at home, or eaten food purchased at a supermarket. Sometimes the source of the food that made people sick is never determined," Tan said.

Tan said the state lab is conducting tests to see if the strain of E. coli bacteria (there are many) match. The CDC will then conduct confirmatory tests.

She said that investigators look for a common food source that made people sick.

"We’re working with the FDA district office in New Jersey, and our own investigators, to trace back sources of food the individuals may have eaten, as well as vouchers of food deliveries made to any of the restaurants that may be part of the investigation."

E. coli, or Escherichia coli, is a bacteria that normally lives harmlessly in the intestines of people and animals, according to the CDC. Some types are pathogenic and can cause illness through exposure to contaminated food or water, or contact with animals or other people. Symptoms include severe stomach cramps, diarrhea (often bloody), and vomiting.

E. coli can be prevented by thorough hand washing after using the bathroom or changing a diaper, before and after food preparation, and contact with animals.

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

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