An Ohio Chipotle Mexican Grill has reopened after reports of illness caused the restaurant to voluntarily shut its doors Monday.

As of 8 a.m. Wednesday, the Delaware County Health District had received 413 inquiries from customers who believed the Powell restaurant's food made them sick, said the district's public information officer, Traci Whittaker.

"Our staff has been fielding calls all day long yesterday, so what happens when we get calls is we have to follow up and investigate," Whittaker said.

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The cause of the illnesses is still unknown, as Whittaker said that investigation takes a significant amount of time. If everything went by the books, the health district would know the potential pathogen by Friday, but it never goes by the books, she said.

First the health district employees have to follow up and interview all of the customers who called, and if they’re willing to provide a stool sample, the health district will send them a kit, pick it up and send it to a lab for testing. More than 30 stool kits have been delivered to those who reported illness.

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The Delaware County Health District will also test leftover food samples some of the customers provided.

The restaurant at 9733 Sawmill Parkway reopened Tuesday after correcting one critical and one noncritical violation related to pinto beans and lettuce being kept at the correct temperature. The restaurant threw all of its food away as well, Whittaker said.

“Our inspection saw no reason for them not to reopen,” she said.

The investigation will continue into next week, she said.

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“We want to look at the whole big picture of what the potential pathogen is, where it came from, what is making these customers sick,” she said

Whittaker said if others were affected and have not yet called the health district, they should do so immediately.

Ron Simon and Associates, along with co-counsel DiCello Levitt and Casey, has filed the first lawsuit in the case against the restaurant.