The ingredient linked to the infection has not been identified, the CDC said. Costco said it stopped selling the chicken salad on Nov. 20, the same day it was notified by federal health officials. The FDA confirmed to the Colorado Department of Public Health and Environment that the chicken salad has been pulled from store shelves in that state. People who bought chicken salad from Costco with item number 37719 must destroy it. Previously, a few days ago, burrito chain Chipotle Mexican Grill Inc was linked to more than 40 cases of E. coli O26 food poisoning in six states. In 1993, E, coli bacteria killed four children who ate undercooked hamburgers at Jack in the Box restaurants.