Investigation Details

July 11, 2019

CDC, public health and regulatory officials in several states, and the U.S. Food and Drug Administration (FDA)external icon investigated a multistate outbreak of E. coli O26 infections.

Public health investigators used the PulseNet system to identify illnesses that may have been part of this outbreak. PulseNet is the national subtyping network of public health and food regulatory agency laboratories coordinated by CDC. DNA fingerprinting is performed on E. coli 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. WGS performed on bacteria isolated from ill people showed that they were closely relatedly genetically. This means that people in this outbreak were more likely to share a common source of infection.

As of July 11, 2019, a total of 21 people infected with the outbreak strain of E. coli O26 were reported from 9 states. A list of the states and the number of cases in each can be found on the Map of Reported Cases page.

Illnesses started on dates ranging from December 11, 2018 to May 21, 2019. Ill people range in age from 7 to 86 years, with a median age of 24. Seventy-one percent of ill people were female. Of 20 people with information available, 3 (15%) were hospitalized. No deaths were reported.

WGS analysis of 21 clinical isolates and one food isolate did not predict resistance to any antibiotics. Testing of three clinical outbreak isolates using standard antibiotic susceptibility testing by CDC’s National Antimicrobial Resistance Monitoring System (NARMS) laboratory also showed no resistance.

Investigation of the Outbreak

Epidemiologic and laboratory evidence, supported by product distribution records, indicated that flour was the likely source of this outbreak.

In interviews, ill people answered questions about the foods they ate and other exposures in the week before they became ill. Of 13 people who were asked, 6 (46%) reported eating, licking, or tasting raw, homemade dough or batter. Three people with detailed information reported eating raw dough or batter made with Baker’s Corner All-Purpose flour.

Investigators with the Rhode Island Department of Health collected records and flour samples at a bakery where an ill person reported eating raw dough. Records indicated that the bakery used Baker’s Corner All Purpose Flour from ALDI. The outbreak strain was isolated from an unopened bag of Baker’s Corner All Purpose Flour collected at the bakery.

WGS results showed that the E. coli O26 strain identified in the Baker’s Corner All Purpose Flour sample was closely related genetically to the E. coli O26 strain identified in ill people. These results provide additional evidence that people in this outbreak got sick from eating flour.

On May 23, 2019, ALDI, in association with ADM Milling Co., recalled pdf icon[PDF – 142 KB]external icon 5 lb. bags of Baker’s Corner All Purpose Flour sold at retail locations in several states because they may be contaminated with E. coli. Additional products were recalled because they may be contaminated with E. coli. For more information about these recalls, visit the FDA websiteexternal icon.

As of July 11, 2019, this outbreak appears to be over.