Chipotle Mexican Grill Inc., has shut down its Massachusetts restaurant voluntarily after four of its employees called in sick.

Company spokesman, Chris Arnold, said in an email that the Billerica location outside of Boston has been temporarily closed for cleaning purposes.

Chipotle has been struggling with a food-safety situation since the first instance of E. Coli breakout was linked to its chain of restaurants by the Centers of Disease Control and Prevention in early November. This particular case brought the customer's attention towards earlier cases of foodborne illnesses faced by some. As the college students in Boston reported sickness after norovirus outbreak, the concerns became deeper and Chipotle sales suffered a massive jolt.

Director of Billerica Board of Health, Richard Berube, announced on Wednesday that Chipotle restaurant will remain closed on the second day after one of its employees tested positive for norovirus. "As a precautionary measure, it might be good to remain closed for another day. Those are the lines I'm thinking along," Berube said.

On Tuesday, all three employees from Chipotle called in sick, Berube said. The other two employees are also allegedly infected with the stomach bug. "Any employees who reported feeling ill will be tested and held out of the restaurant until they fully recover," he added.

With the recent news of Massachusetts location shutting down, Chipotle shares fell by 3.3 percent and closed at 507.30 in New York trading. In the last 20 months, the stock has already faced a 20 percent decline.

The health department of Massachusetts confirmed that the restaurant has closed by its own volition and that there are no reported cases of ill customers.

"Over the last few months, we have been implementing an enhanced food safety plan that will establish Chipotle as an industry leader in food safety," Steve Ells, founder, chairman, and co-CEO of Chipotle, said in a January statement. "Most of the new protocols are already in place, thanks to the hard work and dedication [of] our excellent restaurant teams. Additionally, we have implemented unprecedented food safety standards with our suppliers, which make the food coming into our restaurants safer than ever before."