Deep Dive: Shared Milk Powder Linked Two Infant Botulism Outbreaks — Why Formula Testing Still Skips the Organism That Hospitalized 52 Babies

# Deep Dive: Shared Milk Powder Linked Two Infant Botulism Outbreaks — Why Formula Testing Still Skips the Organism That Hospitalized 52 Babies

**16 October 2026**

Powdered infant formula is one of the most tightly regulated foods in the United States. Finished product must be tested for *Salmonella* and *Cronobacter* before it ships. Yet the organism that put 52 infants in the hospital across two outbreaks in the last year — *Clostridium botulinum* — is still not on that required testing list.

This week a food-safety lawyer posted a draft citizen petition, signed with 23 parents of hospitalized infants, asking the FDA to change that. Comments are invited before he files it by 30 October. The petition is the latest chapter in a story that began with ByHeart formula in late 2025, continued with Nara Organics in spring 2026, and now turns on a single shared dairy ingredient: organic whole-milk powder spray-dried by Dairy Farmers of America from milk supplied by Organic West Milk.

## Background

Infant botulism is rare. Spores of *C. botulinum* can germinate in an infant’s immature gut and produce a toxin that causes descending paralysis. Before 2025, the FDA said no botulism outbreak had ever been definitively tied to infant formula in the United States since the disease was first described about fifty years earlier.

That changed with ByHeart Whole Nutrition Infant Formula. Illnesses stretched from December 2023 through November 2025; 48 infants across 17 states were hospitalized and treated with BabyBIG (human botulism immune globulin). CDC declared that outbreak over in February 2026. Then, in April–May 2026, four more infants in California, Pennsylvania, and Washington developed botulism after consuming Nara Organics Whole Milk Organic Powdered Infant Formula. Nara recalled all lots in mid-June. CDC declared that outbreak over on 27 August 2026.

Whole-genome sequencing later showed a clinical sample from a Nara infant matched a clinical sample, a ByHeart base sample, and four unopened ByHeart cans from the earlier investigation. Traceback found that the implicated Nara lots used milk supplied by Organic West Milk and spray-dried by Dairy Farmers of America — the same suppliers linked to the ByHeart outbreak. FDA has not yet determined whether contamination occurred before or during the drying step, and the root-cause investigation continues. No Nara finished product has tested positive so far, but the genetic and supply-chain overlap is clear.

Current federal rules (21 C.F.R. § 106.55) require finished-product testing only for *Salmonella* and *Cronobacter*. Both form vegetative cells that standard processes can control more readily. *C. botulinum* produces heat-resistant spores that can survive many manufacturing steps and are found in the environment, soil, and some raw ingredients. FDA has written the industry three letters since March 2023 urging better supplier oversight; it has not yet written a rule requiring the test.

## What changed this week

On 15 October 2026, attorney Bill Marler posted a draft citizen petition and asked for comments before filing it by 30 October. The petition, co-signed by 23 parents (21 from the ByHeart outbreak, two from Nara), asks FDA to:

- Add botulinum neurotoxin-producing clostridia to the finished-product testing table at 21 C.F.R. § 106.55(e), with a standard of “none detected.”
- Require testing of the dairy-based ingredients from which powdered formula is made, not only the finished product.
- Finish work that began in a 2023 Call-to-Action letter.

The draft cites 31 footnotes and four appendices and is available on Marler’s site. It notes that in February 2026 FDA sampled 48 powdered-milk samples from four suppliers; two organic nonfat powders tested positive by PCR for a *Clostridium* carrying a botulinum toxin gene and were further analyzed by whole-genome sequencing. A rule aimed only at the plant environment would have missed an ingredient-level problem.

Meanwhile, FDA’s own post-outbreak pages still list ongoing root-cause work, surveillance sampling of powdered milk, and a request that the International Commission on Microbiological Specifications for Foods revisit its guidance on testing for *C. botulinum* in powdered infant formula and dairy ingredients.

## Competing viewpoints

**Parents and advocates** (including the petition signers) argue that 52 hospitalizations is enough evidence. They point to the shared supplier, the genetic match across brands made on different continents, the incomplete customer list Organic West initially gave FDA (which omitted Nara), and the fact that the first Nara illness occurred months after the ByHeart recall. They say voluntary letters have not closed the gap and that requiring the test — both of finished product and of dairy ingredients — is the minimum that protects the next infant. They also note that treatment with BabyBIG is effective but expensive and time-critical; prevention is better.

**Industry and some regulators** have emphasized that both outbreaks are over, that no deaths were attributed to them, that finished-product testing for spores is technically challenging (spores are hard to culture, enrichment methods need validation), and that the root cause is still under investigation. Dairy Farmers of America has stated it does not supply whole-milk powder directly to formula makers; a supplier used its Fallon, Nevada facility. FDA’s July 2026 letter to industry stressed vigilance and supplier knowledge without proposing new mandatory testing. Some manufacturers point to their existing HACCP and environmental monitoring programs and argue that a new required test should wait for a validated method and a clear risk assessment.

**Public-health scientists** note that powdered formula is a low-moisture product in which spores can survive, that infant botulism is almost entirely confined to the first year of life (making this population uniquely vulnerable), and that the two outbreaks in quick succession after decades of none suggest a real supply-chain vulnerability. They generally support better ingredient controls even if finished-product testing remains imperfect.

## What to watch next

- **30 October 2026**: Deadline Marler set for comments on the draft petition before he files it with FDA. Public comments on the docket, once filed, will also matter.
- **FDA root-cause investigation**: Whether the agency publicly identifies the 22 dairies it traced or concludes contamination occurred at the dairy, the dryer, or elsewhere.
- **Method validation**: FDA has mentioned an interim testing method still pending validation. A validated method is a practical prerequisite for a new required test.
- **Legislation**: Bills such as the Infant Formula Safety Modernization Act (H.R. 7867) and a Senate bill that passed by unanimous consent would direct FDA to add *C. botulinum* to the testing list or require notice of confirmed positives. Watch whether either moves in the House.
- **Other brands**: Whether additional formula makers used the same Organic West / DFA powder during the relevant window and whether any residual product remains in homes or warehouses.

## Practical notes for parents

If you used ByHeart or Nara Organics powdered formula in the relevant windows, the recalls are already in effect and both outbreaks are closed. Check any remaining cans against the lot lists published by the companies and FDA and discard them. For current formula, the immediate risk from these specific lots is low, but the broader lesson is that ingredient-level problems can cross brands. Talk with your pediatrician about any feeding concerns; infant botulism symptoms (constipation, weak cry, poor feeding, floppy baby) need prompt evaluation — treatment should not wait for lab confirmation.

This is not medical or legal advice. Official sources: FDA outbreak pages for both investigations, CDC updates, and the draft petition itself.

Sources: FDA outbreak investigation pages (ByHeart and Nara Organics), CDC declarations, Contemporary Pediatrics summaries, Food Safety Magazine, Marler Blog draft petition (15 Oct 2026), and related FDA industry letters.