It was a confusing week in the Chipotle E. coli outbreak investigation. On Tuesday, November 17, the Centers for Disease Control and Prevention (CDC) reduced the number of those sickened in Oregon and Washington from 50 to 37 and said no new cases had been reported since October 30. Three days later, November 20, the agency announced that the outbreak had expanded to include cases in four other states including Minnesota where a case had previously been identified but ruled out as part of the outbreak. That state now has two cases. What’s more, the total number of those ill, now 45, includes two more cases in Washington and three cases that occurred after October 30.
What does it all mean? The contaminated food has not been eliminated from the restaurant’s supply chain as previously thought.
On November 17, the CDC gave no explantation for its reduction in the case count. But the Washington State Department of Health said the numbers were revised because results of more definitive tests became available. The CDC is only counting confirmed cases of E. coli O26 that match the fingerprint of the outbreak strain.
In its November 17 update, the CDC said, “Additional illnesses are under investigation by Washington and Oregon and will be reported if they are confirmed to be infected with the outbreak strain of STEC O26. There have been no reported infections with the outbreak strain of STEC O26 in Washington or Oregon since the Chipotle Mexican Grill locations closed in the Pacific Northwest on October 30, 2015.”
It’s likely that two of the “additional illnesses under investigation” occurring before October 30 were confirmed, as Washington’s total increased by two cases. The other six were from four states as follows: California (2), Minnesota (2), New York (1), Ohio (1).
Of those six cases, one of which had previously been identified but excluded from the case count as the patient did not eat at a Chipotle before becoming ill, three occurred after October 30- two on October 31 and one on November 8.
That means two cases occurred before October 30. Why weren’t they counted earlier? Were the states where they occurred late in uploading them to the PulseNet database used by health officials to track outbreaks?
It also means that whichever food item that is the source of the outbreak was more widely distributed than previously thought and therefore not eliminated from the supply chain with the company’s new companywide safety measures or its extensive efforts in Washington and Oregon which included cleaning, sanitizing, removal of all food, testing of new foods including fresh produce, meats and diary products, and the temporary closure of all 43 stores in those states.
Just what the food source is remains a mystery. Initially, health officials suspected fresh produce. More than 2,500 tests were performed on Chipotle’s food, restaurant surfaces, and equipment and none was positive for E. coli, according to the U.S. Food and Drug Administration.