"Twenty-one cases were reported from nine states. The median age of patients was 24 years (range = 7–86 years); 71% were female. Three patients were hospitalized, and none died. Among 13 patients asked about flour exposures, six reported eating, licking, or tasting raw homemade dough or batter during the week before illness onset. Three patients reported eating raw dough or batter made with the same grocery store brand of all-purpose flour, including a patient who reported eating raw dough at a bakery in Rhode Island. Overall, of 18 patients with store information, 11 reported shopping at this same grocery store chain."
"Flour is increasingly recognized as a cause of STEC outbreaks (1–5). Raw flour is not a ready-to-eat product, and this outbreak highlights the continuing risk for illness associated with consumption of flour and raw dough or batter."
https://www.cdc.gov/mmwr/volumes/70/wr/mm7016a4.htm
Notes from the Field: Multistate Outbreak of Escherichia coli O26 Infections Linked to Raw Flour — United States, 2019
Weekly / April 23, 2021 / 70(16);600–601
Michael Vasser, MPH1,2; Jonathan Barkley, MPH3,4; Adam Miller, MS3,5; Ellen Gee6; Katherine Purcell7; Morgan N. Schroeder, MPH1; Colin Basler, DVM1; Karen P. Neil, MD1 (View author affiliations)