POWELL, OH (WCMH/CNN) - Health officials think they have figured out what sickened almost 650 people who ate at an Ohio Chipotle restaurant.
The good news is unsanitary employees are likely not to blame. The bad news is the diagnosis suggests food at the restaurant was not kept at the correct temperature.
The Delaware County General Health District said five of six stool samples taken from people who got sick after eating at the Chipotle location tested positive for the pathogen clostridium perfringens.
"It is a bacteria that grows in food that is not kept at the correct time and temperature," said Delaware County Health Commissioner Shelia Hiddleson.
Ohio uniform safety code states hot foods must be held at 135 degrees and above and cold foods 41 degrees or less.
"There are so many things that can happen when you're preparing food, and time and temperature is the most important," Hiddleson said. "We always try to tell people keep hot things hot, cold things cold."
What hasn't been identified is the food or foods that made 647 people sick. Food samples all came back negative.
Brian Niccol, CEO of Chipotle said leadership will be retraining all restaurant employees nationwide, beginning next week, on food safety and wellness protocols.
Hiddleson said they worked around the clock to crack the county's largest-ever foodborne disease outbreak.
"Our staff have done an amazing job," she said. "We have about 80 staff on hand, and at one point or another in the last couple of weeks we've had over 50 staff working on all of this."
According to the Centers for Disease Control and Prevention, the bacteria can grow at temperatures between 54 and 140 degrees. It can be killed easily if food is heated above this temperature range prior to serving.