Infant botulism outbreak linked to powdered formula under FDA investigation

A multistate outbreak of infant botulism linked to powdered infant formula has prompted an ongoing investigation by the FDA, the CDC, and multiple state and local public health partners. According to federal officials, the outbreak represents the first known instance of infant botulism associated with infant formula since the condition was first described nearly 50 years ago.^1,2

Infant botulism is a rare but serious illness caused by spores of Clostridium botulinum, a bacterium commonly found in the environment, including soil and dust. While ingestion of spores is typically harmless to older children and adults with mature gastrointestinal systems, infants can develop life-threatening illness if viable spores produce neurotoxin after ingestion.

Multistate outbreak investigation underway

FDA and CDC, in collaboration with the California Department of Public Health (CDPH) Infant Botulism Treatment and Prevention Program and other partners, are investigating cases of infant botulism associated with ByHeart Whole Nutrition infant formula. CDC has identified 51 infants from 19 states with suspected or confirmed infant botulism and confirmed exposure to the product. All 51 infants were hospitalized. No deaths attributed to this outbreak have been reported.

The FDA first became aware of a cluster of illnesses on November 6, 2025, and began an investigation. After consultation with CDC, CDPH, and state partners, the agency recommended a voluntary recall to the manufacturer on November 7, 2025. The FDA issued a public warning to consumers on November 8, 2025, and the recall was expanded on November 11, 2025, to include all lots of infant formula produced by ByHeart. Recalled products include all formula cans and single-serve “anywhere pack” sticks, which should no longer be available for sale.

Preliminary laboratory testing reported by CDPH on November 8, 2025, suggested the presence of Clostridium botulinum in an open can of formula fed to an infant with diagnosed botulism. On November 20, 2025, the manufacturer reported that third-party laboratory analysis of some retained samples of unopened formula identified Clostridium botulinum. Testing by FDA, CDC, state laboratories, and the company is ongoing, and most FDA samples have preliminarily tested negative.

Differences in bacterial contamination risks

Federal officials emphasized that spore-forming bacteria such as Clostridium botulinum differ substantially from more commonly discussed pathogens in powdered infant formula, including Cronobacter and Salmonella. Non–spore-forming organisms such as Cronobacter and Salmonella do not form protective spores and are susceptible to pasteurization, whereas spore-forming bacteria can survive typical pasteurization and persist in harsh environmental conditions for extended periods.

Detection of spore-forming bacteria also differs from traditional pathogen testing. Laboratory analysis may require specialized methods and extended timelines, with final results sometimes taking two weeks or longer. In addition, the presence of spores alone may not determine risk because not all spores are viable or capable of producing toxin.

These differences have implications for prevention, environmental monitoring, and testing strategies in infant formula manufacturing and supply chains.

Public health response and ongoing research

According to FDA officials, “This is the first known botulism outbreak tied to infant formula anywhere in the world since infant botulism was first described as a distinct clinical entity almost 50 years ago.”

As part of the response, FDA has initiated additional sampling of dairy-based ingredients, including whole milk powder, non-fat dry milk powder, and whey protein concentrate, to evaluate the supply chain and inform next steps. The agency is also collaborating with industry, academic experts, and public health partners to improve understanding of Clostridium botulinum and strategies for risk reduction.

FDA stated, “The FDA and our partners will remain vigilant for any signs that infants are becoming ill from formula exposure from any cause. As we did in this case, if we detect such a signal, the FDA will act swiftly to protect our most vulnerable population.”

In addition, the FDA is working with international experts and standard-setting bodies to conduct a risk assessment on Clostridium botulinum in infant formula. The assessment will consider available data and may inform future control measures and manufacturing practices. Ongoing efforts also include collaboration with the Joint FAO/WHO Expert Meeting on Microbiological Risk Assessment and the Codex Committee on Food Hygiene to strengthen scientific guidance related to microbiological hazards in powdered infant formula.

Future risk assessment and scientific review activities will depend on findings from the ongoing investigation. FDA officials indicated that additional risk assessment work may be pursued as more information becomes available and welcomed submission of scientific evidence that may inform recommendations related to infant formula safety.

For clinicians, the outbreak underscores the importance of recognizing infant botulism, counseling caregivers about product recalls, and remaining aware of evolving guidance as the investigation continues.

References

1. FDA. FDA’s Actions to Respond to Clostridium botulinum Illnesses Associated with Consumption of Powdered Infant Formula. FDA. February 5, 2026. Accessed Februdary 5, 2026. https://www.fda.gov/food/outbreaks-foodborne-illness/fdas-actions-respond-clostridium-botulinum-illnesses-associated-consumption-powdered-infant-formula
2. Fitch J. FDA, CDC investigating multistate infant botulism outbreak tied to formula. Contemporary Pediatrics. November 11, 2025. Accessed February 5, 2026. https://www.contemporarypediatrics.com/view/fda-cdc-investigating-multistate-infant-botulism-outbreak-tied-to-formula