An outbreak of infant botulism linked to ByHeart powdered infant formula has ended, according to the US Centers for Disease Control and Prevention.

The final tally of victims comprises 28 confirmed cases and 20 probable cases from 17 states. No new cases have been added since December of 2025, and three previously reported suspected cases from 3 different states have been excluded from the totals.

Illnesses in this outbreak first began on December 24, 2023 and continued through November 29, 2025. The 48 victims ranged in age from 16 to 264 days old. All were hospitalized and treated with BabyBIG®. There were no deaths.

Outbreak cases were reported in Arizona (5), California (12), Idaho (2), Illinois (2), Kentucky (1), Massachusetts (2), Michigan (1), Minnesota (3), North Carolina (2), New Jersey (1), Oregon (3), Pennsylvania (1), Rhode Island (1), Texas (8), Virginia (1), Washington (2), and Wisconsin (1).

Epidemiological and laboratory analysis established ByHeart Whole Nutrition infant formula as the source of the illnesses. The company recalled all of its infant formula products on November 11, 2025.

Although the outbreak is officially over, the FDA‘s investigation into the root cause of the contamination continues.

In addition to the finding of Clostridium botulinum in opened and sealed cans of infant formula by the California Department of Pubic Health, the New York State Department of Health, and the company itself, the FDA recovered the pathogen from a sample of organic whole milk powder from Organic West Milk, which supplies the ingredient to ByHeart. The milk powder was processed for Organic West Milk by a Dairy Farmers of America (DFA) facility.

Spores of Clostridium botulinum are found in soil around the world, and the pathogen has been known to infect dairy herds. Although the FDA has not yet released any firm conclusions regarding the root cause of the contamination, if these heat-stable spores were in the raw organic milk delivered to DFA for processing, they would have been able to survive the heat of pasteurization and remain viable in the finished powdered milk.

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