On January 25, 2026, the FDA and CDC, with the California Department of Public Health (CDPH), Infant Botulism Treatment and Prevention Program (IBTPP), and other state and local partners, continue to investigate a multistate outbreak of infant botulism. Epidemiologic and laboratory analyses indicate that ByHeart Whole Nutrition infant formula is the source of this multistate outbreak of infant botulism. No new cases have been added to the investigation since December 10, 2025. Product sampling and testing are being conducted by the FDA, CDC, state partners, and ByHeart. Additionally, the FDA collected ByHeart ingredient samples for analysis, as part of the investigation. As of January 23, 2026, two samples collected by the FDA tested positive for Clostridium botulinum (toxin), Type A. One is a ByHeart powdered infant formula closed product sample that matches a clinical isolate from an infant included in this outbreak, as determined by WGS analysis. These samples also match two isolates of organic whole milk powder, an ingredient used in the production of ByHeart Whole Nutrition powdered infant formula, which were collected and tested by ByHeart. The second organic whole milk powder sample was collected by the FDA at a processor for a supplier to ByHeart and analyzed by the New York Wadsworth Laboratory. WGS analysis showed that the Clostridium botulinum found in the sample of organic whole milk powder is a genetic match to the Clostridium botulinum detected in the finished product sample of ByHeart’s infant formula, according to analysis conducted by ByHeart. Previously, on December 23, 2025, ByHeart publicly reported positive test results for Clostridium botulinum in 6 of 36 finished product samples. These six samples were taken from two batches, which were both included in the initial product recall. This is the first documented outbreak of botulism in the United States attributed to contaminated infant formula, and there are fundamental differences between spore-forming bacteria like Clostridium botulinum and vegetative bacteria such as Cronobacter and Salmonella. These are important considerations as the FDA continues to respond to this outbreak and to implement risk-reduction strategies going forward. All ByHeart infant formula products have been recalled. FDA continues to receive reports that recalled formula is still being found on store shelves, despite the ongoing recall of all ByHeart infant formula products. FDA continues to work with state partners and retailers to ensure an effective recall and immediate removal of these products from store shelves across the country. The outbreak caused a total of 51Illnesses,51 hospitalizations, and no deaths. States with Cases are AZ, CA, ID, IL, KY, MA, ME, MI, MN, NC, NJ, OH, OR, PA, RI, TX, VA, WA, and WI. @ https://www.fda.gov/food/outbreaks-foodborne-illness/outbreak-investigation-infant-botulism-infant-formula-november-2025?utm_medium=email&utm_source=govdelivery
