FDA presses infant formula makers to tighten supplier oversight after botulism and cereulide events

The FDA has sent a letter to infant formula manufacturers and their supply chain partners calling for stronger oversight of ingredient suppliers, citing 2 recent US outbreaks of infant botulism and a global contamination event tied to a shared formula ingredient.¹ The letter does not announce new regulation; instead, it functions as a direct appeal for industry to close gaps that the agency says have repeatedly allowed contaminated ingredients to reach finished product.¹

The agency's letter states that manufacturers are expected to understand where their ingredients originate, how they are produced, what risks they may carry, and whether those risks are effectively controlled — and to act quickly once a supplier concern is identified, whether flagged by FDA or caught through a company's own monitoring.¹ For clinicians who counsel families on infant feeding, the update is a reminder that recent formula-related illness has consistently traced back to the supply chain rather than to finished-product handling in the home.

Recent outbreaks driving the warning

FDA investigated 2 separate multistate outbreaks of infant botulism linked to powdered infant formula from different brands, ByHeart, Inc. and Nara Organics, Inc., both resulting in voluntary recalls and an ongoing agency investigation into shared ingredient suppliers.¹ In the ByHeart outbreak, epidemiologic and laboratory evidence identified the company's Whole Nutrition formula as the outbreak source; 48 infants were hospitalized and treated with human botulism immune globulin, and case review ultimately expanded to include illnesses dating back to December 2023.² FDA and CDC investigators cultured Clostridium botulinum type A from both an opened product sample fed to a sick infant and later from unopened cans, indicating the contamination occurred before the product reached families.²

A separate, larger event unfolded internationally between late 2025 and early 2026, when cereulide, a heat-stable toxin produced by Bacillus cereus, was traced to contaminated arachidonic acid (ARA) oil, a common ingredient added to formula to approximate breast milk's fatty-acid profile.³ The World Health Organization reported 144 suspected and confirmed cases across 10 countries as of late February 2026, prompting recalls of multiple international brands and the addition of an ARA oil supplier to FDA import alerts.¹³ Because cereulide withstands standard heat processing, contamination is not eliminated by the pasteurization or drying steps typical of formula manufacturing.³

What FDA is asking of industry

The letter asks manufacturers and their supply chain partners to actively track recall notifications, outbreak investigations, and import alerts, framing these as safety signals that should trigger internal review rather than be dismissed as isolated events affecting only the named company.¹ FDA acknowledged there is no single validated approach to controlling spore-forming organisms such as C botulinum in formula ingredients and said it plans to continue working with academic experts and international bodies, including the Codex Committee on Food Hygiene and the International Commission on Microbiological Specifications for Foods, to identify best practices.¹

Where the investigation stands

FDA said its root-cause investigation into the 2025 and 2026 domestic botulism outbreaks is ongoing and that initial surveillance work characterizing the prevalence of C botulinum in powdered milk ingredients has been completed, with results posted to the agency's post-outbreak response webpage.¹⁴ The agency has not yet identified how spores entered the supply chain in either US outbreak, and international authorities likewise have not completed a full traceability analysis of the ARA oil implicated in the cereulide event.³ For now, the letter represents an advisory escalation rather than a mandated new testing requirement, leaving specific verification methods to individual manufacturers.

References

1. US Food and Drug Administration. FDA calls on infant formula industry to better safeguard against contaminants introduced through their supply chain. Constituent update. July 13, 2026. Accessed July 13, 2026. https://www.fda.gov/food/hfp-constituent-updates/fda-calls-infant-formula-industry-better-safeguard-against-contaminants-introduced-through-their

2. US Food and Drug Administration. Outbreak investigation of infant botulism: infant formula (November 2025). Accessed July 13, 2026. https://www.fda.gov/food/outbreaks-foodborne-illness/outbreak-investigation-infant-botulism-infant-formula-november-2025

3. World Health Organization. Infant formula and products containing arachidonic acid oil contaminated with cereulide toxin - multi-country. Disease Outbreak News. March 2026. Accessed July 13, 2026. https://www.who.int/emergencies/disease-outbreak-news/item/2026-DON596

4. US Food and Drug Administration. Post-outbreak response activities: Clostridium botulinum illnesses associated with consumption of powdered infant formula. Accessed July 13, 2026. https://www.fda.gov/food/outbreaks-foodborne-illness/post-outbreak-response-activities-clostridium-botulinum-illnesses-associated-consumption-powdered