Costco chicken salad linked to E. Coli outbreak

Authorities say chicken salad from Costco has been linked to cases of E. coli food poisoning in Washington, Montana, California, Utah, Colorado, Missouri and Virginia.

The Department of Health, the Centers for Disease Control and Prevention and other western states are investigating E. coli illnesses from chicken salad purchased from various Costco stores in late October.

Officials are working to determine the source.

Consumers who purchased chicken salad made with rotisserie chicken - item number 37719 - from any Costco location should discard it. People who have eaten it and feel ill should talk to a health care provider.

The CDC released the following statement on Tuesday:

Initial Announcement

CDC, the U.S. Food and Drug Administration, the U.S. Department of Agriculture Food Safety and Inspection Service, and public health officials in several states are investigating an outbreak of Shiga toxin-producing Escherichia coli O157:H7 (STEC O157:H7) infections.

Public health investigators are using the PulseNet system to identify illnesses that may be part of this outbreak. PulseNet, the national subtyping network of public health and food regulatory agency laboratories, is coordinated by CDC. DNA "fingerprinting" is performed on E. coli bacteria isolated from ill people by using a technique called pulsed-field gel electrophoresis, or PFGE. PulseNet manages a national database of these DNA fingerprints to identify possible outbreaks.

One DNA fingerprint (outbreak strain) is included in this investigation. A total of 19 people infected with the outbreak strain of Shiga toxin-producing STEC O157:H7 have been reported from 7 states. The majority of illnesses have been reported from states in the western United States. The number of ill people reported from each state is as follows: California (1), Colorado (4), Missouri (1), Montana (6), Utah (5), Virginia (1), and Washington (1).

Among people for whom information is available, illnesses started on dates ranging from October 6, 2015 to November 3, 2015. Ill people range in age from 5 years to 84, with a median age of 18. Fifty-seven percent of ill people are female. Five (29%) people reported being hospitalized, and two people developed hemolytic uremic syndrome (HUS), a type of kidney failure. No deaths have been reported.

This outbreak can be illustrated with a chart showing the number of people who became ill each day. This chart is called an epidemic curve or epi curve. Illnesses that occurred after November 10, 2015, might not be reported yet due to the time it takes between when a person becomes ill and when the illness is reported. This takes an average of 2 to 3 weeks. Please see the Timeline for Reporting Cases of E. coli Infection for more details.

CDC and state and local public health partners are continuing laboratory surveillance through PulseNet to identify additional ill persons and to interview them.

Investigation of the Outbreak

The epidemiologic evidence available to investigators at this time suggests that rotisserie chicken salad made and sold in Costco stores is a likely source of this outbreak. The ongoing investigation has not identified what specific ingredient in the chicken salad is linked to illness.

State and local public health officials are interviewing ill people to obtain information about foods they might have eaten and other exposures in the week before their illness started. Fourteen (88%) of 16 people purchased or ate rotisserie chicken salad from Costco.

On November 20, 2015, Costco reported to public health officials that the company had removed all remaining rotisserie chicken salad from all stores in the United States and stopped further production of the product until further notice.

Updates will be provided when more information is available.