FDA Releases Findings from ByHeart Infant Formula Botulism Investigation
Following a serious infant botulism outbreak linked to ByHeart-brand formula in late 2025 and early 2026, the U.S. Food and Drug Administration (FDA) has published detailed findings from its onsite inspections of ByHeart’s production facilities and one of its key suppliers. The outbreak, which affected 48 infants across 17 states, was officially declared over on February 26, 2026.
While earlier FDA inspection reports from 2023 had revealed food safety and hygiene violations at a now-closed ByHeart facility—and the company had received an FDA warning letter that same year—the agency’s recent investigation did not identify these prior issues as contributing factors to the 2025–2026 outbreak.
Contaminated Powdered Milk Ingredient Identified as Source
Both the FDA and ByHeart’s independent root cause investigations pointed to Clostridium botulinum contamination in a powdered milk ingredient. However, no additional factors were found to explain how the contamination occurred or spread.
The FDA also inspected Dairy Farmers of America, the processor for Organic West Milk, a supplier to ByHeart. Whole genome sequencing (WGS) analysis of C. botulinum isolates recovered from two samples of the same lot of organic whole milk powder matched the strain found in a clinical isolate and a positive infant formula finished product sample. An ongoing root cause analysis, with a particular focus on ingredients, continues at the FDA.
ByHeart Commits to Enhanced Food Safety Measures
ByHeart has announced it is developing a comprehensive action plan to strengthen food safety protocols based on data and findings from the outbreak investigation. The plan includes a new C. botulinum testing protocol with heightened sensitivity, developed in collaboration with a third-party laboratory partner.
A ByHeart representative confirmed that this testing protocol will be applied to “every dairy ingredient and to finished batches before they are released from [ByHeart’s] facilities.” The company plans to publish updates about the developing action plan on its website.
FDA Expands Efforts to Prevent Future Outbreaks
Beyond the ongoing root cause analysis, the FDA is taking additional steps to prevent future infant botulism cases. These include surveillance sampling to better assess the presence of C. botulinum in powdered milk and efforts to better understand the risks associated with the pathogen in infant formula.
The agency has also advocated for the Joint FAO/WHO Expert Meetings on Microbiological Risk Assessment (JEMRA) to conduct a risk assessment on spore-forming pathogens, including Clostridium botulinum and Bacillus cereus, in powdered infant formula. Additionally, the FDA supported the Codex Committee on Food Hygiene’s request for JEMRA to update existing risk assessments on Cronobacter and Salmonella in powdered infant formula and provide scientific advice on strengthened control measures across all stages of production—from primary production and packaging to reconstitution and environmental monitoring.
