A mysterious outbreak that seemingly sickened hundreds of Chipotle customers in Ohio might finally have a known culprit. On Thursday, health officials reported that traces of a common foodborne bug called Clostridium perfringens had been found in some of the victims’ stool samples. It’s likely the outbreak was spread by improperly heated food.
The latest fracas to dent Chipotle’s food safety reputation began in late July. From July 26 onward, people who ate at the Chipotle location on Sawmill Parkway in Powell, Ohio, came down with symptoms such as nausea, vomiting, and diarrhea. On July 30, the Delaware General Health District shut down the restaurant for inspection. Though no further cases appeared after it was reopened, health officials ultimately identified 645 people who became sick within that time period.
Initial tests of victims’ stool for other common foodborne germs, such as norovirus, Salmonella, and E. coli came back negative. But the Centers for Disease Control and Prevention identified signs of a toxin that’s produced by some disease-causing strains of C. perfringens, an ubiquitous rod-shaped bacteria found in the environment and in our guts.
Like other stomach bugs, many strains of C. perfringens, including those that live in our gut, are harmless. But the toxin-making kinds often spell trouble for people. They’re estimated to cause more than a million cases of foodborne illness annually, according to the CDC. While the symptoms of C. perfringens generally amount to a 24-hour stomach flu, it can rarely become fatal.
Part of what makes the germ so pernicious is its ability to harden into spores that can withstand hot temperatures. Undercooked food, as well as cooked food that’s left out sitting without enough heat or cold, can reawaken these spores, allowing them to quickly grow and become infectious again.
There were no signs of C. perfringens within the Chipotle food samples tested directly, but health officials say an earlier inspection of the restaurant on July 26 found food preparation violations, including not heating beans and not chilling lettuce enough, Business Insider reported. Similar violations were also found at nearby Chipotle restaurants.
“I am extremely proud of our team! This investigation included countless hours of phone calls and interviews along with multiple inspections,” said Delaware County Health Commissioner Shelia Hiddleson in a statement Thursday.
Chipotle is already running damage control. On Thursday, the company’s recently enshrined CEO, Brian Niccol, announced in a statement that Chipotle will spend next week retraining all of its staff on “food safety and wellness protocols.”
“Chipotle has a zero-tolerance policy for any violations of our stringent food safety standards and we are committed to doing all we can to ensure it does not happen again,” Niccols said.
Of course, outbreaks aren’t just Chipotle’s problem. Also on Thursday, the Food and Drug Administration announced in an update that at least 476 people across 15 states are confirmed to have been sickened by salads they ate at a McDonald’s restaurant, thanks to the Cyclospora parasite. No cases of this outbreak have been reported since July 20, however, and McDonald’s has stopped using the lettuce supplier thought to be the source of the contaminated vegetables.
The CDC is continuing to test food and stool samples from the Chipotle outbreak.