Fifty-one babies in 19 states have been hospitalized with infant botulism after consuming ByHeart Whole Nutrition infant formula, federal officials confirmed last month.
Infant botulism can be fatal, according to the U.S. Food and Drug Administration (FDA). Patients typically initially develop constipation, poor feeding, loss of head control and difficulty swallowing — which can lead to difficulty breathing and respiratory arrest.
Symptoms can take several weeks to develop. No deaths related to ByHeart have yet been reported.
A California program that provides the only treatment for infant botulism was the first to identify a surge in cases among babies who had consumed ByHeart formula.
The FDA has been carrying out a multi-state investigation into an outbreak of infant botulism tied to powdered infant formula since November 2025.
The 51 cases the agency identified were initially believed to have started in 2025. However, as early as December 2023, the investigation identified one case linked to ByHeart’s formula.
In its most recent update, the FDA reported it identified the bacteria that can cause botulism in two samples linked to ByHeart’s formula.
The agency said it found the bacteria in an unopened can of ByHeart formula that genetically matched the botulism infecting one of the sick infants.
The FDA also found contamination in a sample of whole milk powder supplied to ByHeart. The powder matched the germ in a finished sample of the company’s formula.
ByHeart announced in December 2025 that its own investigation found the bacteria in six of 36 samples it tested.
The FDA said its investigation is ongoing, and that testing for Clostridium botulinum is complex — the process can take weeks, and only a few labs in the U.S. can do it.
ByHeart told ABC News that the event is a “watershed moment” for the company. “We are focused on the root cause and our responsibility to act on what we’ve learned to help create a safer future for ByHeart and infant formula,” said Dr. Devon Kuehn, ByHeart’s chief scientific and medical officer.
FDA warns parents to immediately stop using ByHeart products
At first, ByHeart recalled only two lots of the formula. But days later, the company expanded the recall to all of its products.
Federal health officials later said they could not rule out contamination of all ByHeart products made since the company launched in March 2022.
The FDA and the Centers for Disease Control and Prevention (CDC) recommend that parents and caregivers immediately stop using any ByHeart formula.
On Dec. 15, 2025, the FDA issued a letter to retailers, manufacturers and others involved in distributing food, after learning that ByHeart products were still being found on store shelves. The letter stated:
“Ultimately, it is the responsibility of all industry stakeholders involved in a recall, including retailers and distributors, to ensure that affected products are promptly removed from commerce and do not reach consumers.”
The agency said it continues to receive reports that the product can be found on store shelves despite recall efforts.
‘Disrupting’ the baby formula industry?
This is the first botulism outbreak linked to contaminated infant formula, the FDA said. According to food safety experts who spoke with ABC News, the size and scope of the ByHeart outbreak are unprecedented.
ByHeart is a New York-based company that calls itself the first “next generation baby nutrition company.” Billed as an industry “disruptor,” it launched its infant formula in 2022 to “innovate” baby food.
The company raised more than $400 million in venture capital funding between 2020 and 2025.
ByHeart conducted its own clinical trials on its bovine-based formula before launch. They said the formula is designed to be more similar to breast milk than any other formula.
At the time of the recall, ByHeart accounted for about 1% of the U.S. infant formula market, the FDA said. Before the recall, the company sold about 200,000 cans of the product per month.
Parents of babies sickened in the outbreak said they chose the formula, which cost about $42 per can, because of its touted health benefits, according to ABC News.
Food Safety attorney Bill Marler, who is representing more than 30 families of babies diagnosed with infant botulism, reported that ByHeart has hired “big firm lawyers” who are “hiring experts, serving subpoenas and ignoring requests to step up to pay medical expenses and wage losses incurred by these families — all whose children were hospitalized — all the while depleting the limited insurance that ByHeart has to compensate these infants.”
On its website, ByHeart said it has halted all production while it investigates the issue and is offering refunds to people who purchased its products. It does not say anything about compensating injured infants and their families.
The company maintains that its testing protocols exceeded industry standards. Neither ByHeart nor the FDA has named the milk suppliers they use for their products. ByHeart said it does not know whether those suppliers are also supplying other companies.
The company did not respond to The Defender’s request for comment.

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ByHeart is top sponsor of the American Academy of Pediatrics
The American Academy of Pediatrics (AAP) reported the outbreak on its news website.
In its reporting, the AAP did not mention that ByHeart is a major funder of AAP — part of its “President’s Circle” of only 10 annual donors that donate at least $50,000 to the organization.
Other members of AAP’s President’s Circle include pharmaceutical giants Pfizer, Merck, Moderna and Sanofi.
ByHeart was also a “proud sponsor” of the AAP’s National Conference & Exhibition, which took place in September 2025.
The AAP is currently facing a lawsuit, filed by Children’s Health Defense and five other plaintiffs, accusing it of running a decades-long racketeering scheme to defraud American families about the safety of the childhood vaccine schedule.
That racketeering allegedly includes colluding with companies in the president’s circle.
The AAP did not respond to The Defender’s request for comment on its relationship with ByHeart.
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