As of November 14, the number of infant botulism cases linked to consumption of ByHeart formula has grown to 23 across 13 states. ByHeart Inc. has recalled all lots of its infant formula products, sold in stores and online nationwide.

The California Department of Public Health’s (CDPH’s) Infant Botulism Treatment and Prevention Program (IBTPP) first notified federal public health agencies about a spike of infant botulism hospitalizations, occurring from August 1–November 10, 2025, and totaling 84 cases. IBTPP operates the only global source of infant botulism treatment worldwide. Subsequently, an investigation was launched by the U.S. Food and Drug Administration (FDA), the U.S. Centers for Disease Control and Prevention (CDC), CDPH’s IBTPP, and other state and local partners.

Outbreak and Investigation Statistics

Epidemiological and laboratory data point to ByHeart Whole Nutrition infant formula as the vehicle of illness in 23 infant botulism cases occurring within this spike. According to a November 11 update from FDA, of the 84 infants who fell ill, 36 were formula-fed. ByHeart is disproportionately represented in this outbreak, given that the company is responsible for producing only 1 percent of the U.S. formula supply, yet is implicated in at least 23 of 36 (64 percent) cases with formula exposure.

The 23 cases have been reported in Arizona (three), California (three), Illinois (two), Kentucky (one), Michigan (one), Minnesota (two), North Carolina (two), New Jersey (one), Oregon (two), Pennsylvania (one), Rhode Island (one), Texas (three), and Washington (one). These 23 infants had confirmed exposure to various ByHeart formula lots. All cases resulted in hospitalization, and no deaths have been reported. Onset of illness information is available for 22 of these cases, which ranges between August 9 and November 11.

Preliminary laboratory test results from CDPH identified the presence of Clostridium botulinum in an open can of ByHeart infant formula (lot 206VABP/251131P2) that was fed to an infant with infant botulism. 

As part of the investigation, officials in several states have collected additional samples of leftover infant formula from affected consumers for testing, the results of which are pending.

Investigations remain ongoing but have not identified any other infant formula brands or shared exposures that pose a risk to infants.

ByHeart: Evidence “Lacks Scientific Basis to Establish Causation”

In the company’s statements, ByHeart Inc. asserted that the preliminary test results are not enough to definitively link its product to the outbreak, saying, “neither [ByHeart], nor FDA or CDC, have found Clostridium botulinum spores or toxins in any unopened can of ByHeart formula,” and added that a positive sample from an open can of formula “lacks scientific basis to establish causation between the product and illness.”

At the same time, FDA underscores that detection of C. botulinum in infant formula is difficult, and a negative test result does not rule out the presence of the bacteria in the product.  

ByHeart Food Safety and Hygiene Failures Predating the Botulism Outbreak

According to FDA inspection reports and warning letters, ByHeart Inc. has a history of food safety and hygiene violations at its production facilities, including issues like mold, dead insects, and reoccurring roof leaks at its Reading, Pennsylvania facility, causing the plant to be shut down earlier in 2023.

Additionally, the firm received a warning letter from FDA in 2023 after a batch of finished product tested positive for Cronobacter sakazakii, prompting an investigation of the production facility. Not only did FDA find a roof leak in a production area, and lapses in Standard Operating Procedures (SOPs) and cleaning and sanitation verification activities that could allow microbiological contamination to occur, but the agency also reprimanded ByHeart for failing to conduct a comprehensive root cause analysis of the C. sakazakii contamination. In fact, ByHeart concluded from its root cause analysis that the C. sakazakii positive test result was a laboratory error—which FDA said was contrary to the evidence.

Update, November 19, 2025: The number of infant botulism cases linked to consumption of ByHeart formula has grown to 31 across 15 states. 

Update, November 26, 2025: ByHeart Inc. has found Clostridium botulinum Type A in five of 36 samples across three lots. “Based on these results, we cannot rule out the risk that all ByHeart formula across all product lots may have been contaminated,” said the company.

As of November 26, the number of infant botulism cases in the associated outbreak has grown to 37 across 17 states. Additionally, FDA has released ByHeart facility inspection reports from as early as 2022 showing a history of food safety breaches.

Update, December 3, 2025: A total of 39 infants with suspected or confirmed infant botulism and confirmed exposure to ByHeart Whole Nutrition infant formula (various lots) have been reported across 18 states. All 39 infants were hospitalized; no deaths have been reported.