Chipotle is once again under the microscope. The fast food chain is now under investigation by the FDA.
A grand jury is looking into a string of foodborne illness that left hundreds of people sick. The popular restaurant has been subpoenaed to turn over internal documents.
Last summer, a norovirus outbreak sickened 18 employees in California and then spread to 189 customers who ate at the restaurant.
Most norovirus cases are caused when someone who's sick fails to practice good hygiene. That could be topic of conversation when Chipotle will close down stores nationwide for one day in early February.
"The procedures we are putting in place today are so above industry norms that we are going to be the safest place to eat," said Steve Ells, Chipotle's CEO.
As far as the grand jury investigation, Chipotle has declined to comment on that.
E-coli bacteria has also been linked to Chipotle products.
The food chain has announced that December sales are down 30 percent and it's stock fell to a two year low, down 43 percent since October.