Published: June 07, 2026, 06:42 UTC
The Food and Drug Administration this week closed its investigation into a devastating infant botulism outbreak linked to contaminated formula, but critics say the agency still has no answers on how the contamination happened or how to prevent a repeat. Three companies at the center of the crisis are pointing fingers at each other, with none taking public responsibility.
The outbreak
Forty-eight infants across 17 states were hospitalized with botulism after consuming ByHeart brand powdered infant formula. The outbreak was identified in early November 2025 and declared over by the FDA and Centers for Disease Control and Prevention on February 26, 2026. Some infants are still recovering months after the life-threatening infection.
Botulism in infants is caused by Clostridium botulinum spores that germinate in the immature gut and produce a neurotoxin, causing flaccid paralysis. Symptoms start with constipation, poor feeding, and loss of head control, and can progress to respiratory arrest.
The supply chain trail
The FDA’s investigation traced the contamination with unusual precision. Strains of C. botulinum isolated from sick infants were genetically linked to strains found in ByHeart’s formula, which were in turn linked to powdered whole milk used as an ingredient. That powder was dried from liquid milk at a Dairy Farmers of America facility in Nevada. The liquid milk came from supplier Organic West in California. Organic West sold the resulting powder to ByHeart.
Specifically, contaminated formula and milk powder traced back to eight whole milk lot powders derived from 33 fluid milk lots from Organic West, according to an FDA incident summary.
The finger-pointing
Despite this clear trace, the FDA’s final report offered no definitive root cause. “The FDA’s investigation into the root cause is ongoing with a focus on ingredients,” the agency stated.
Each company in the chain has deflected responsibility. ByHeart pointed to its suppliers. Dairy Farmers of America highlighted that its testing and pasteurization processes were within normal parameters. Organic West stressed that its raw milk tested negative for botulism spores before shipment. Meanwhile, ByHeart noted on its website that “FDA Concludes Facility Inspections, Identifying No Deficiencies Tied to Botulism Outbreak.”
Ars Technica, which first reported on the FDA’s underwhelming conclusion, noted that the three companies have effectively created a circular logic where no single entity can be held accountable.
What’s missing
Critics point to a broader gap: the FDA’s food safety framework relies on companies detecting pathogens in finished products, but C. botulinum spores are ubiquitous in soil and can enter the supply chain at any point. Unlike Salmonella or E. coli, botulism spores survive standard pasteurization temperatures. The only reliable kill step is retort sterilization, which is not used for powdered infant formula because it would degrade nutritional quality.
The FDA has said it is pursuing post-outbreak response activities including additional surveillance, prevention strategies, and compliance activities. But without a root cause, those efforts lack a clear target. The agency acknowledged its root cause investigation, with a focus on ingredients, is ongoing.
The bigger picture
Infant formula is one of the most tightly regulated food categories in the United States, precisely because infants are uniquely vulnerable to contamination. The 2022 formula shortage triggered by the Abbott Nutrition plant closure in Sturgis, Michigan exposed how fragile the supply chain is. Three years later, a different pathogen found a way through.
The outbreak raises a question regulators have not answered: if standard testing and pasteurization cannot catch botulinum spores in powdered formula, what should the industry do differently?
Sources: Ars Technica (June 6, 2026); FDA (June 2026); ByHeart (June 2026)