Chipotle Mexican Grill said on Thursday it may never pinpoint what caused an E. coli outbreak last month linked to two restaurants in Kansas and Oklahoma, extending a mystery over dozens of illnesses tied to the burrito chain.
Chipotle no longer has any of the potentially contaminated ingredients that could be examined to determine the source of the infections, company spokesman Chris Arnold said. “It is doubtful that testing will ever be able to determine for sure what the cause of this was,” he said.
Company and health officials investigating the outbreak have also cited the same hurdles to tracing the cause of a larger E. coli outbreak which has sickened at least 50 Chipotle customers in nine states since October.
Chipotle has been under a microscope for months as customer illnesses stemming from E. coli and norovirus have battered sales and the company’s stock price.