Infant Botulism Outbreak Declared Over, Investigation into Formula Root Cause Continues

The Centers for Disease Control and Prevention (CDC) has declared an outbreak of infant botulism linked to ByHeart Whole Nutrition infant formula to be over, following extensive investigation and case reviews. While the immediate outbreak has concluded, the U.S. Food and Drug Administration (FDA) continues its inquiry into the underlying causes that led to the contamination of the formula, with a focus on ensuring future infant formula safety.

The investigation, conducted in collaboration with various state and local health departments, identified ByHeart Whole Nutrition infant formula as the source of a multistate outbreak of infant botulism. The outbreak involved a total of 48 illnesses, with 28 confirmed and 20 probable cases. All affected infants were hospitalized, though thankfully, no deaths were reported. The last reported illness onset occurred on November 29, 2025. Cases were reported across 17 states, including Arizona, California, Idaho, Illinois, Kentucky, Massachusetts, Michigan, Minnesota, North Carolina, New Jersey, Oregon, Pennsylvania, Rhode Island, Texas, Virginia, Washington, and Wisconsin.

In response to the findings, all ByHeart Whole Nutrition infant formula products, encompassing both cans and single-serve “anywhere pack” sticks, were subject to a recall. This recall impacted product availability nationwide and internationally, with distribution to numerous countries including Argentina, Brazil, Canada, China, and Japan, among others. Despite the recall, reports indicated that recalled formula was still being found on store shelves, prompting continued efforts by the FDA and retailers to ensure complete removal from sale.

Scientific analysis, including whole genome sequencing (WGS) of samples, has been crucial in identifying the presence of Clostridium botulinum. Isolates from clinical cases have been matched with genetic sequences found in both finished product samples and ingredient samples, such as organic whole milk powder used in the formula’s production. The FDA collected samples from Dairy Farmers of America, the processor for Organic West Milk, a supplier to ByHeart. While these laboratory findings provide significant evidence, the complexity of Clostridium botulinum and the limited available scientific data mean the FDA has not yet definitively determined the root cause(s) of contamination. Ongoing research and sample analysis are being conducted to further inform these conclusions.

The FDA is transitioning its response from immediate containment to post-incident activities. This includes continued surveillance, along with prevention and compliance measures. The agency is committed to understanding the factors that contributed to this outbreak and implementing strategies to safeguard the safety of powdered infant formula moving forward. Information regarding the FDA’s ongoing efforts and general formula safety can be found on the agency’s dedicated webpage.

Parents and caregivers who have used ByHeart infant formula are strongly advised to discontinue its use immediately. If an infant has consumed ByHeart formula and is exhibiting symptoms of infant botulism, such as constipation, poor feeding, loss of head control, difficulty swallowing, or breathing difficulties, they should seek immediate medical attention. If an infant has consumed the formula but is not showing symptoms, they should be monitored closely, and medical care sought if any symptoms develop. It is also recommended to wash any items or surfaces that may have come into contact with the formula using hot, soapy water or a dishwasher.

Physicians suspecting a case of infant botulism are advised to contact their respective state’s clinical support line for consultation.

Article by Mel Anara, based upon information from the U.S. Food and Drug Administration.

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