A significant outbreak of infant botulism has been linked to contaminated ByHeart formula, affecting at least 51 infants across 19 states, according to the U.S. Food and Drug Administration (FDA). On December 10, 2023, officials confirmed that all affected infants were hospitalized, although no fatalities have been reported to date. The outbreak has prompted a nationwide recall of ByHeart products, which are believed to contain the botulinum toxin.
On the same day, the FDA updated the number of confirmed or suspected illnesses, which had previously stood at 39 cases across 18 states. The increase is attributed to a broader definition of the outbreak, now encompassing cases identified from December 2023 to July 2025. The illnesses reportedly began between August 9 and November 19, 2023, with cases documented in states including Arizona, California, Kentucky, and Wisconsin, among others.
The FDA has confirmed that it has not received reports of recalled formula being found on store shelves since the recall announcement on November 26, 2025. In a statement, the FDA emphasized that all ByHeart infant formula products should be removed from sale, including both cans and single-serve stick packs. Despite the ongoing recall, some consumers reported seeing the products still available at major retailers such as Walmart and Target.
Investigation and Response
The FDA, along with the Centers for Disease Control and Prevention (CDC) and state health partners, is conducting additional testing. Results are expected in the coming weeks. ByHeart, which has a small market share of about 1% in the U.S., has stated that it is cooperating with health authorities to ensure public safety. The company has sold approximately 200,000 cans of the formula monthly since its introduction.
Dr. Erica Pan, California’s state health officer, confirmed that a sample from an open can of ByHeart formula, which was fed to an affected infant, tested positive for the botulinum bacterium. The testing protocol involves injecting cultured bacteria into mice to confirm contamination, a process that revealed rapid illness onset in the test subjects.
In light of the findings, ByHeart has advised parents and caregivers to immediately discontinue use of the product and dispose of any remaining formula. The company released a statement on its website outlining its commitment to food safety and the steps taken to address potential risks. ByHeart’s previous recalls, including a major recall in 2022 due to contamination concerns with another bacterium, have raised questions about the company’s manufacturing practices.
Health Implications of Botulism
Botulism is a rare but serious illness that can result in paralysis and may be fatal. Symptoms typically take weeks to manifest and can include poor feeding, loss of head control, drooping eyelids, and a flat facial expression. The condition is particularly dangerous for infants, who are vulnerable due to their underdeveloped gut microbiomes.
The only treatment for infant botulism is known as BabyBIG, an intravenous medication derived from the pooled blood plasma of adults immunized against botulism. All affected infants in this outbreak have received this treatment, which is known to cost approximately $69,300 per vial.
Experts have noted that the current outbreak is unlikely to lead to widespread formula shortages, given ByHeart’s small market share compared to larger manufacturers. This contrasts sharply with the significant formula shortages experienced in late 2021 and 2022, when a different bacterium caused severe illness and led to a nationwide crisis.
The FDA’s investigation continues, with officials remaining vigilant in monitoring the situation. As the outbreak develops, further updates will be provided to ensure the safety of infants across the country.
