The incident raises specters of the string of foodborne illness outbreaks that devastated the Denver-based chain in 2015. The restaurant experienced repeated outbreaks of E. coli, salmonella and norovirus in a six-month period, forcing it to take the extraordinary step of temporarily closing more than 2,000 locations in February 2016 to conduct employee food-safety training.

Chipotle has spent the months since then attempting to persuade fleeing customers that its food is safe.

AD

AD

In a statement, Chipotle’s executive director of food safety, Jim Marsden, said the company has notified local health officials to resolve the situation and believes the store will reopen later on Tuesday.

“The reported symptoms are consistent with norovirus,” Marsden said. “Norovirus does not come from our food supply, and it is safe to eat at Chipotle.”

This is not Chipotle's first encounter with norovirus, a highly contagious and common virus that infects between 19 and 21 million people per year, according to the Centers for Disease Control and Prevention. It is easily spread when a person who is ill prepares food, does not wash their hands before preparing food, or does not properly sanitize the work surfaces they have come into contact with. According to the CDC, fruits and vegetables can also be contaminated in the field — though contamination in the kitchen is more common.

AD

AD

In August 2015, 207 people reported falling ill with the virus after eating at a Chipotle in Simi Valley, Calif., prompting an unusual federal inquiry into the chain's food-safety practices.

In December of that year, 80 Boston College students also fell ill after eating at a location near campus. In response, Steve Ells, the company's chief executive officer, apologized on NBC's “Today” show and promised that the company's reformed food-safety procedures would be the best in the business.

Since then, however, the chain has had to work hard to rehab its once-pristine reputation. It hired a number of food-safety experts to identify problems in its supply chain and launched an expensive ad campaign to draw customers back. As of the fourth quarter of 2016, same-store sales were improving — albeit not to the point where they were before the outbreaks happened.

AD

AD

During a December conference call with investors, Chief Marketing Officer Mark Crumpacker said that “the data, everything that we have, suggest there are not large numbers of customers staying away from Chipotle” because of food-safety problems.

Experts say they don't believe consumers have reason to fear, either. Bill Marler, a lawyer who specializes in foodborne illness cases, said Chipotle had taken impressive steps to reverse its food-safety record — including hiring Marsden, formally a professor at Kansas State University, to head its cleanup efforts.

Marler cites the company's quick response to the Sterling outbreak as evidence it has changed: The location immediately and voluntarily closed for a “full sanitation,” which Marler said many chains of similar size might not do for a small norovirus outbreak.