WASHINGTON (AP) — The federal agency that monitors public health says the outbreak of E. coli illness linked to Chipotle restaurants that sickened 60 people appears to be over.
The Centers for Disease Control and Prevention said Monday the most recent illness reported to the agency started on Dec. 1.
Although the CDC closed its investigation, the source of the illness that spread to 14 states is still unknown. Chipotle executives say they may never be able to identify what made people sick.
Denver-based Chipotle Mexican Grill Inc. undertook an aggressive revamping of food preparation methods at its more than 1,900 locations. But the outbreak drove the company's stock down by 26 percent over the past three months and it warned in December of a potentially sizeable hit to profits.
Its stock rallied following the CDC announcement. By mid-afternoon, Chipotle's shares were up $14.09, or 3 percent, at $467.06.
"We are pleased that the CDC has concluded its investigation, and we have offered our full cooperation throughout," the company said in a statement. It added that it's confident that changes in its preparation methods mean all its food is "delicious and safe."
People usually get sick from Shiga toxin-producing E. coli, the bacteria commonly associated with foodborne outbreaks, for two to eight days after swallowing the germ, according to the agency. Most infected people get diarrhea and abdominal cramps.
The Chipotle episode began last summer when the chain was tied to foodborne illnesses in California and Minnesota, though those cases didn't get as much attention.
Then, at the end of October, E. coli cases were reported in Oregon and Washington, prompting the company to shut down 43 restaurants in those states. YouGov Brand Index said customer perceptions about Chipotle sank to their lowest level since it began tracking the company in 2007. That was before additional cases popped up in seven more states.
In November, Chipotle sales plunged 16 percent. Then, an unrelated norovirus outbreak sickened dozens of students at Boston College. And in December, the CDC reported five more cases of E. coli the previous month linked to Chipotle, which it said might be part of a different outbreak.
The company disclosed last month that it's been subpoenaed by federal prosecutors and the U.S. Food and Drug Administration as part of a criminal investigation. It has also said it plans to open stores at 3 p.m. local time on Feb. 8 to hold meetings with employees to discuss changes concerning food-safety measures. The chain also plans to increase its marketing and direct-mail offers this month.
This story has been corrected to show that Chipotle warned of a potential sizeable hit to profits in December, not last month.