FDA’s Actions to Respond to Clostridium botulinum Illnesses Associated with Consumption of Powdered Infant Formula
Infant botulism is a rare but serious illness caused by spores from a bacterium called Clostridium botulinum. These spores are naturally found in the environment including in soil and sediments (dust) and can enter manufacturing facilities and home environments from hands, shoes, and other contaminated surfaces. The 2025 infant botulism outbreak is unique with a spike in illnesses associated with a particular infant formula, and both FDA and the firm, ByHeart, Inc. (ByHeart) are conducting root cause investigation. At this time, the investigation has not indicated a broader problem in the infant formula supply.
This is the first known botulism outbreak tied to infant formula anywhere in the world since infant botulism was first described as a distinct clinical entity almost 50 years ago. As a result of this outbreak, FDA is working with international experts and standard setting bodies to conduct a risk assessment on Clostridium botulinum in infant formula, which will consider all available data.
The FDA and our partners will remain vigilant for any signs that infants are becoming ill from formula exposure from any cause. As we did in this case, if we detect such a signal, FDA will act swiftly to protect our most vulnerable population.
Bacterial spores, including Clostridium botulinum spores, are known to be present at low levels in many foods. Infants might ingest Clostridium botulinum spores from their food or environment. These spores are generally harmless to older children and adults with mature, healthy digestive systems. However, they can pose a life-threatening risk to infants who ingest viable spores that produce a toxin that affects the nervous system.
There are fundamental differences between bacteria that form spores like Clostridium botulinum and those that do not, such as Cronobacter and Salmonella. These differences are crucial to understanding food safety contamination risks and assessing testing strategies.
- Non-spore-forming bacteria (e.g., Cronobacter and Salmonella) do not form protective spores. While dangerous, they are susceptible to pasteurization.
- Spore-forming bacteria (e.g., Clostridium botulinum) are incredibly resilient. They can create a protective spore that allows them to survive typical pasteurization and harsh environmental conditions for long periods. This makes the spores more difficult to eliminate from food processing environments. Additionally, the mere presence of spores alone may not be determinative of risk, as not all spores are viable and cause illness.
- Spore-forming bacteria analysis and laboratory detection methods differ from traditional pathogen detection methods requiring additional time and specialized resources, which limits the number of labs with testing capacity. The complex testing process can take two or more weeks for final results.
These two categories of bacteria present distinct contamination risks and require different prevention and testing strategies due to their vastly different survival capabilities and environmental presence. These are important considerations as FDA continues to respond to the 2025 infant botulism outbreak and implements risk reduction strategies going forward.
Overview of recent Clostridium botulinum illnesses and contamination of powdered infant formula
FDA and CDC, in collaboration with the California Department of Public Health (CDPH) Infant Botulism Treatment and Prevention Program (IBTPP) and other state and local partners, are investigating a multistate outbreak of infant botulism linked to ByHeart Whole Nutrition infant formula. FDA and CDC issued warnings about ByHeart infant formula in November 2025, after CDPH IBTPP reported an increase in the number of botulism infections among infants consuming ByHeart powdered infant formula.
CDC has identified 51 infants from 19 states with suspected or confirmed infant botulism and confirmed exposure to ByHeart Whole Nutrition infant formula. This includes the expanded case count from December 24, 2023, to December 1, 2025. All 51 infants were hospitalized, and no deaths attributed to this outbreak have been reported to date. FDA first became aware of this cluster of illnesses on November 6, 2025, and immediately began its investigation. On November 7, 2025, after consulting with CDC, CDPH, and partners in states with ill infants, the FDA spoke with the firm to recommend voluntary recall and on November 8, 2025, the FDA issued a public warning to consumers. The recall was subsequently expanded on November 11, 2025 to include all lots of infant formula produced by ByHeart.
All ByHeart infant formula products have been recalled, and these products should not be available for sale in stores or online. This includes all formula cans and single-serve “anywhere pack” sticks. As part of this investigation, ByHeart, FDA, and state laboratories have tested unopened containers of ByHeart infant formula and raw materials used in making ByHeart infant formula. On November 8, 2025, preliminary laboratory results reported by CDPH suggested the presence of Clostridium botulinum in an open can of ByHeart infant formula that was fed to an infant with diagnosed botulism. On November 20, 2025, ByHeart reported that third-party laboratory analysis of some samples of unopened infant formula products retained at its facility identified Clostridium botulinum.
Testing is ongoing by FDA, CDC, state partners, and ByHeart. The majority of FDA samples have preliminarily tested negative for the presence of Clostridium botulinum; all finished product positives are being reported in the Outbreak Advisory.
Actions FDA is taking to respond to the 2025 infant botulism outbreak:
- Continued investigation to learn more about the root cause of the outbreak.
- Initiated a sampling assignment focused on dairy-based ingredients, including whole milk powder, non-fat dry milk powder, and whey protein concentrate to help evaluate the supply chain and inform next steps.
- Broaden scientific knowledge and understanding of Clostridium botulinum and public health interventions for controlling it.
- Enhance communications and engagement with industry, consumers, federal, state, local, and other public health partners about infant formula safety.
Collaborate with stakeholders on what could be done to enhance safety: FDA continues to have ongoing collaboration with industry members, coalition groups, academia, and consumers/consumer groups, to discuss and engage in dialogue to better understand risks associated with Clostridium botulinum and best practices for the manufacturing of powdered infant formula.
On March 8, 2023, FDA issued a Letter to Industry on areas of concern based on inspections of powdered infant formula manufacturing facilities. The FDA emphasized that manufacturers must identify and consider all known or reasonably foreseeable biological hazards associated with powdered infant formula, including Clostridium botulinum.
Conduct and support research to help fill knowledge gaps in the scientific understanding of Clostridium botulinum: FDA advocated for the Joint FAO/WHO Expert Meeting on Microbiological Risk Assessment (JEMRA) to conduct a risk assessment on spore-forming pathogens, including Clostridium botulinum and Bacillus cereus, in powdered infant formula. FDA has also supported the Codex Committee on Food Hygiene request to JEMRA to 1) update the existing risk assessment and scientific advice on Cronobacter and Salmonella in powdered infant formula and 2) provide other relevant scientific advice that would inform recommendations on strengthened control measures across infant formula production, covering all stages from primary production and packaging to the reconstitution of the product and including environmental monitoring.
Future risk assessment and scientific review activities will depend on the findings of our ongoing investigation. FDA will evaluate the need for additional risk assessment work as we gather more information about the 2025 infant botulism outbreak and its contributing factors. FDA welcomes any and all scientific evidence that can inform recommendations on this important public health matter.
Frequently Asked Questions (FAQs)
FDA, in collaboration with our federal, state and local partners, is investigating a multistate outbreak of infant botulism. Epidemiologic and laboratory data show that ByHeart Whole Nutrition infant formula has been associated with infant illness caused by Clostridium botulinum in the United States. Parents and caregivers should stop using any ByHeart infant formula products immediately, as ByHeart Whole Nutrition Infant Formula products have been recalled. This includes all lots of formula cans and single-serve “anywhere pack” sticks. FDA’s investigation, including onsite inspections and sample collection, is ongoing to determine the point of contamination. For the most up-to-date information, please refer to the FDA Outbreak Advisory.
ByHeart infant formula products makes up approximately 1% of all infant formula sold in the U.S. and this outbreak does not create shortage concerns of infant formula for parents and caregivers.
The current outbreak of Clostridium botulinum is associated with consumption of ByHeart infant formula. At this time, no other products, formula or otherwise, have exhibited an unusual illness pattern that would indicate potential contamination, although FDA remains vigilant.
While this investigation is linked to the ByHeart brand of infant formula, parents and caregivers of infants can reduce the overall botulism risk by avoiding high-risk foods like honey and corn syrup (which can contain Clostridium botulinum spores), following proper formula preparation instructions, and maintaining good hygienic practices when preparing infant food.
When a firm initiates a voluntary recall, the firm is responsible for notifying its direct customers and ensuring that recalled products are removed from the marketplace immediately. FDA works with the recalling firm throughout the recall process to ensure that all distribution channels are notified and responsive to the recall. Due to the vulnerable population associated with this recall event FDA took steps to coordinate with state and local partners when it came to effectuating the recall efforts. One way FDA verifies the effectiveness of a firm’s recall efforts is by conducting Recall Audit Checks. The recall audit check process evaluates if notifications are being received by distributors and retailers, if they took appropriate action, and includes follow up discussions with related firms as needed. So far, FDA, state, and local partners have conducted over 4,300 checks. Despite these efforts, FDA has continued to receive reports of the product being available for sale as recently as January 18, 2026. In response, FDA coordinated follow-up actions for each instance, including visiting facilities, notifying responsible parties to help ensure the recall was properly effectuated, and ultimately issuing four warning letters to retailers. In addition, FDA may issue public communications such as safety advisories, consumer warnings, or recall notices to inform the public and help protect consumers. FDA also amplifies messaging through social media platforms such as Facebook, X, LinkedIn, etc. For more information on FDA’s verification efforts during this this recall, visit https://www.fda.gov/news-events/press-announcements/fda-takes-action-improve-recall-effectiveness-following-infant-botulism-outbreak-investigation. For updates on FDA's outbreak investigation, we refer you to: Outbreak Investigation of Infant Botulism: Infant Formula (November 2025) | FDA
Current methods for the detection of C. botulinum in infant formula require multiple steps on specialized equipment, with final results often taking weeks to confirm. FDA is working with partners to improve and update these methods, so that results can be confirmed and compared across stakeholders more quickly.
Consumers can consider using liquid ready-to-feed formula, as this is the safest option for higher risk formula-fed infants. If you can’t obtain liquid ready-to-feed formula, consider using a liquid concentrate. Both liquid ready-to-feed formula and liquid concentrate are made to be sterile (without germs) and are safer options than powdered infant formula for higher risk infants not receiving breast milk. If using liquid concentrate formula and you are uncertain about the safety of your water source, be sure to boil the water for making formula, then let it cool in the pot for five minutes before putting it in the bottle. Add the liquid concentrate, shake to mix and allow the formula to cool to room temperature before feeding your infant.