Health officials are reportedly investigating soup-and-sandwich chain Panera Bread after a cluster of E. coli cases sprung up in four New Jersey counties.
The New Jersey Department of Health said it is looking into eight cases of E. coli in the state that led to hospitalization. Five of the patients have been discharged from hospitals, it said.
NJ.com reported that Panera Bread was the focus of the investigation, particularly a Phillipsburg location.
Sarah Perramant, public health epidemiologist in Warren County, told NJ.com that the Warren County Health Department and the state health department were investigating several E. coli cases that may have been from "local Panera Breads."
The New Jersey Department of Health said the other affected counties are Hunterdon, Middlesex and Somerset.
The department declined to disclose the name of the restaurant.
"The Department is investigating a possible association with a chain restaurant, but the association may be broader than a single chain restaurant," it said in a statement.
The department told CNBC that the investigation is still evolving and it is possible that as the department gathers more information, more than just one restaurant or restaurant brand could be associated with the outbreak.
"It can be very difficult to determine where someone got sick," the department said in a statement. "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. 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."
When asked about the E. coli outbreak, Panera directed CNBC to the health department's statement.
The New Jersey agency is in the process of doing lab tests to determine if the strain of E. coli, of which there are many, matches. Then the federal Centers for Disease Control and Prevention will conduct its own tests.