The CDC reports no new cases of infant botulism linked to ByHeart formula.
New Key Finding: As of January 23, 2026, two samples collected by FDA tested positive for Clostridium botulinum type A: One is a ByHeart powdered infant formula closed product sample that matches a clinical isolate from an infant included in this outbreak according to whole genome sequencing (WGS) analysis. These samples also match two isolates of whole milk powder, an ingredient that ByHeart uses in the production of ByHeart Whole Nutrition powdered infant formula, which were collected and tested by ByHeart.
The second whole milk powder sample was collected by FDA at a supplier to ByHeart and analyzed by the New York Wadsworth Laboratory. WGS analysis showed that the Clostridium botulinum found in the sample of 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.
Investigation details
CDC, public health and regulatory officials in several states, the Infant Botulism Treatment and Prevention Program (IBTPP), and the U.S. Food and Drug Administration (FDA) are collecting different types of data to investigate a multistate outbreak of infant botulism.
Epidemiologic and laboratory data show that ByHeart Whole Nutrition infant formula is contaminated with Clostridium botulinum and has made infants sick.
Laboratory data
FDA, CDC, state partners, and ByHeart are conducting product sampling and testing. Additionally, FDA collected ByHeart ingredient samples for analysis, as part of the investigation.
FDA testing
As of January 23, 2026, two samples collected by FDA tested positive for Clostridium botulinum type A:
One is a ByHeart powdered infant formula closed product sample that matches a clinical isolate from an infant included in this outbreak according to whole genome sequencing (WGS) analysis. These samples also match two isolates of whole milk powder, an ingredient that ByHeart uses in the production of ByHeart Whole Nutrition powdered infant formula, which were collected and tested by ByHeart.
The second whole milk powder sample was collected by FDA at a supplier to ByHeart and analyzed by the New York Wadsworth Laboratory. WGS analysis showed that the Clostridium botulinum found in the sample of 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.
While these results advance FDA’s understanding of the outbreak, FDA’s investigation is ongoing to determine the source of contamination.
ByHeart testing
On December 23, 2025, ByHeart publicly reported positive test results for Clostridium botulinum in six of 36 samples of finished product. These six samples were taken from two batches (batch 251261P2 and batch 251131P2), which were both included in the initial product recall.
Additional testing
Sample analysis is ongoing, and additional results will be reported as they become available. The detection of Clostridium botulinum in infant formula, or its ingredients, is complex, and confirmation of results can take several weeks.