CDC: Chipotle's E. Coli Outbreak Apparently Over Last illness linked to outbreak started on Dec. 1 By Newser Editors and Wire Services Posted Feb 1, 2016 3:48 PM CST 10 comments Comments This Sunday, Dec. 27, 2015, file photo, shows a Chipotle restaurant in Union Station in Washington. (AP Photo/Gene J. Puskar, File) (Newser) – 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. "We are pleased that the CDC has concluded its investigation, and we have offered our full cooperation throughout," the company says in a statement. It added that it's confident that changes in its preparation methods mean all its food is "delicious and safe." 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% 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%, at $467.06. The company disclosed last month that it's been subpoenaed by federal prosecutors and the US Food and Drug Administration as part of a criminal investigation. It has also said it plans to open stores at 3pm local time on Feb. 8 to hold meetings with employees to discuss changes concerning food-safety measures.