Outbreak Summary

CDC collaborated with public health and regulatory officials in several state and the U.S. Department of Agriculture’s Food Safety and Inspection Service to investigate a multistate outbreak of Salmonella Typhimurium infections.

Public health investigators used the PulseNet system to identify illnesses that were part of this outbreak. PulseNet is the national subtyping network of public health and food regulatory agency laboratories coordinated by CDC. DNA fingerprinting was performed on Salmonella bacteria isolated from ill people by using techniques called pulsed-field gel electrophoresis (PFGE) and whole genome sequencing (WGS). CDC PulseNet manages a national database of these DNA fingerprints to identify possible outbreaks. WGS gives a more detailed DNA fingerprint than PFGE.

A total of 265 people infected with the outbreak strains of Salmonella Typhimurium were reported from 8 states. A list of the states and the number of cases in each can be found on the Case Count Map page. WGS performed on bacteria isolated from ill people showed that they were closely related genetically. This means that people in this outbreak were more likely to share a common source of infection.

Illnesses started on dates ranging from January 8, 2018, to March 20, 2018. Ill people ranged in age from less than 1 year to 89 years, with a median age of 57. Sixty-seven percent of people were female. Ninety-four hospitalizations were reported, including one person from Iowa who died.

WGS analysis did not identify predicted antibiotic resistance in 112 of 127 isolates (110 samples from ill people and 2 from food). Fifteen isolates from ill people contained genes for resistance to all or some of the following antibiotics: amoxicillin-clavulanic acid, ampicillin, cefoxitin, ceftriaxone, gentamicin, streptomycin, sulfamethoxazole, and tetracycline. This resistance is unlikely to affect the treatment of most people, but some infections might be difficult to treat with antibiotics usually prescribed and may require a different antibiotic. Standard antibiotic resistance testing methods were used by CDC’s National Antimicrobial Resistance Monitoring System laboratory on clinical isolates from three ill people in this outbreak. These isolates were not resistant to any antibiotics tested.

Investigation of the Outbreak

Epidemiologic, laboratory, and traceback evidence indicated that chicken salad produced by Triple T Specialty Meats, Inc. and sold at Fareway grocery stores was the likely source of this multistate outbreak.

Public health officials in IowaExternal first detected this outbreak and linked the illnesses to chicken salad sold at Fareway grocery stores. CDC searched the PulseNet database and identified illnesses in other states, and those illnesses were added to this outbreak. In interviews, ill people answered questions about the foods they ate and other exposures in the week before they became ill. Of 222 people interviewed, 194 (87%) reported eating chicken salad purchased from Fareway grocery stores. Triple T Specialty Meats, Inc. produced the chicken salad that ill people reported eating.

On February 9, 2018, Fareway stopped selling chicken salad in all of its stores after the Iowa Department of Inspections and Appeals contacted the company about the illnesses. The Iowa Department of Public Health and the Iowa Department of Inspections and Appeals issued a consumer advisory on February 13, 2018 warning that chicken salad sold at Fareway may be contaminated with Salmonella.

Investigators in Iowa collected chicken salad from two Fareway grocery store locations in Iowa for laboratory testing. An outbreak strain of Salmonella Typhimurium was identified in both samples.

On February 21, 2018, Triple T Specialty Meats, Inc. recalledExternal all chicken salad produced from January 2, 2018 to February 7, 2018. The recalled chicken salad was sold in containers of various weights from the deli at Fareway grocery stores in Iowa, Illinois, Minnesota, Nebraska, and South Dakota from January 4, 2018 to February 9, 2018.

As of April 6, 2018, this outbreak appears to be over.