FDA concludes botulism probe without identifying root cause in ByHeart formula outbreak

The US Food and Drug Administration has concluded its investigation into a botulism outbreak linked to infant formula manufactured by ByHeart, yet it has failed to identify the specific point in the supply chain where contamination occurred. The regulator posted a summary of its post-outbreak response activities this week, a move that critics, including lawyer Bill Marler, have described as underwhelming due to the lack of clear guidance for consumers or companies moving forward.

The outbreak, which was identified in early November and officially declared over by the FDA and the Centers for Disease Control and Prevention on 26 February, resulted in the hospitalisation of 48 infants across 17 states. Some children remain in recovery months after the life-threatening infection, which is caused by Clostridium botulinum bacteria producing a neurotoxin that leads to flaccid paralysis.

Genetic tracing established a clear link between the strains of bacteria found in the sick infants and those in ByHeart’s formula. The investigation further connected the formula to powdered whole milk supplied by Organic West and processed by Dairy Farmers of America at a facility in Nevada. Specifically, the FDA traced contaminated formula and milk powder back to eight whole milk lot powders derived from 33 fluid milk lots from Organic West, a California-based supplier.

Despite these connections, the FDA stated that investigational findings could not identify the source or root cause of the contamination. The agency noted that while several hypotheses exist, it could not determine how the spores entered the production line or how to prevent similar incidents in the future.

In the absence of regulatory clarity, the three companies involved have publicly blamed one another. ByHeart stated that the FDA identified no deficiencies in its facilities that could explain the root cause. Dairy Farmers of America attributed responsibility to Organic West, asserting that its processing met all required tests and arguing that end-use manufacturers are responsible for properly processing ingredients. Organic West owner Bill Van Ryn stated that nothing has been proven about their milk yet.

Bill Marler, who is representing 25 of the sickened infants, argued that ultimate responsibility lies with ByHeart as the manufacturer of the final product. He emphasised that sourcing, verifying, and testing ingredients is the job of the formula maker. Meanwhile, ByHeart is working with a laboratory to develop more sensitive testing for C. botulinum and is attempting to resume infant formula production.