The Los Angeles County health department is investigating reports of illnesses by customers who ate at a Chipotle.
Chipotle says it has not directly received any complaints from customers and was not aware of any reports made to local health officials.
The burrito chain said it only knew of complaints on "user-generated reporting sites," but did increase preventative measures at the undisclosed location.
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"We take any report of illness very seriously," said Chipotle spokesperson Chris Arnold. "...we have not been contacted by customers directly to substantiate these claims."
The spokesman said they were implementing "heightened preventative procedures at this restaurant, which we do as a matter of policy if we ever receive reports of illness (even if they are not substantiated)."
Media reports indicate the restaurant in question is the Mid-Wilshire area location at 4550 W. Pico Bouelvard.
Chipotle has struggled to regain the confidence of customers after an E. coli outbreak in 2015. Last summer, a Chipotle in Virginia had to close temporarily after diners fell ill.
Shares in Chipotle Mexican Grill Inc. fell more 3 percent, to about $303 per share, in afternoon trading. That's less than half of what they were at their 2015 peak, before the E. coli outbreak.