The number of infants sickened by a rare but serious illness tied to ByHeart baby formula has climbed to at least 15 across 12 states, according to health officials, sparking urgent recalls and a federal investigation. The outbreak, which began in mid-August 2025, has drawn national attention to infant formula safety and prompted the first comprehensive federal review of formula ingredients in nearly three decades.
California’s Department of Public Health confirmed that nine cases of infant botulism type A have been verified, with results pending for six more children. The affected infants, ranging in age from just 2 weeks to 5 months, all required hospitalization after consuming ByHeart powdered formula, as reported by the U.S. Centers for Disease Control and Prevention (CDC). Thankfully, no deaths have been reported, but the gravity of the situation has left parents and officials deeply concerned.
The CDC and the Food and Drug Administration (FDA) are working in tandem with state agencies to investigate the outbreak. ByHeart, a New York-based maker of organic baby formula, responded by recalling two lots of its Whole Nutrition Infant Formula over the weekend prior to November 10, 2025. The recalled lots—206VABP/251261P2 and 206VABP/251131P2—carry best-by dates of December 2026.
“Consumers in possession of this product should stop using it immediately,” the California Department of Public Health cautioned in a public statement, echoing the urgency of the recall. The CDC confirmed that all affected infants had been fed ByHeart formula from the recalled lots, and emphasized that additional testing is underway to determine if unopened cans are also contaminated.
California health officials examined a sample from an open can of ByHeart formula that had been fed to one of the sick infants. The results were striking. Testing involved injecting laboratory mice with the cultured bacteria, a process that can take up to four days to confirm illness. “These mice got sick really quickly,” Dr. Erica Pan, a California health officer, told the Associated Press. This rapid onset strongly suggested the presence of the bacteria responsible for producing the dangerous botulism toxin.
ByHeart, for its part, has stressed the need for further testing. In a statement, the company said, “Testing unopened cans will provide reliable evidence that will help bring clarity to families who are understandably concerned.” The company also noted that the bacteria family involved includes many strains that do not cause illness—making precise identification and confirmation essential.
Since August 2025, at least 84 babies nationwide have been treated for botulism, including those confirmed to have consumed ByHeart formula. The FDA is still investigating whether additional cases are linked to the same product. Most years, infant botulism affects fewer than 200 babies in the U.S., making this outbreak, and its association with powdered formula, especially alarming. As Dr. Steven Abrams, a University of Texas nutrition expert, told the Associated Press, “This would be extremely rare.”
Infant botulism is caused by bacteria that produce a potent toxin in the large intestine. The culprit is a hardy spore found in the environment, capable of causing severe illness—including paralysis—when it germinates in the underdeveloped digestive systems of babies under one year old. Infants can be exposed to these spores in dust, dirt, water, or through contaminated food, such as honey. Symptoms can take weeks to appear and may include poor feeding, loss of head control, drooping eyelids, a flat facial expression, floppiness, and difficulty swallowing or breathing.
The only treatment for infant botulism is BabyBIG, an intravenous medication made from the pooled blood plasma of adults immunized against botulism. Developed by California’s Infant Botulism Treatment and Prevention Program, BabyBIG is the sole source of this life-saving medication worldwide. It’s not cheap—a single vial costs $69,300, according to Dr. Pan—but it’s proven to shorten hospital stays and decrease the severity of illness. Because the infection can impair breathing, many affected infants require ventilator support. The CDC confirmed that all children sickened in the ByHeart outbreak have received BabyBIG.
Despite the recall and growing case count, officials say there is little risk of a nationwide formula shortage. ByHeart, founded in 2016, accounts for about 1% of total U.S. formula sales, distributing its products through its website and retail stores. This stands in stark contrast to the crisis of late 2021 and 2022, when Abbott Nutrition’s formula was linked to a different germ, cronobacter sakazakii, resulting in the closure of a major Michigan plant and a months-long nationwide shortage. While two infants died in that earlier crisis, no direct link was established between Abbott’s products and the infections, though the FDA did find contamination at the plant.
ByHeart itself was not immune to scrutiny before this current outbreak. In 2022, the company recalled five batches of infant formula after a sample at its packaging plant tested positive for cronobacter sakazakii—the same germ at the heart of the Abbott crisis. Then, in 2023, the FDA issued a warning letter to ByHeart, citing “areas that still require corrective actions.”
Now, the ByHeart outbreak has reignited debate about formula safety and oversight. Federal health officials have pledged to overhaul the U.S. food supply, with a particular focus on infant formula. Health Secretary Robert F. Kennedy Jr. has tasked the FDA with reviewing the nutrients and other ingredients in formula as part of an initiative dubbed “Operation Stork Speed.” This marks the first deep review of formula ingredients since 1998. The FDA is currently soliciting feedback from industry professionals, health experts, and the public to help guide its next steps.
For many families, the news has been both alarming and confusing. ByHeart has advised consumers to check their formula’s lot numbers and immediately discontinue use of any recalled product. The company has also pledged to cooperate fully with regulators and to provide updates as more test results become available.
As the investigation continues and more information comes to light, the ByHeart outbreak serves as a sobering reminder of the importance of food safety—especially when it comes to the most vulnerable members of society. While the risk to the broader formula supply remains low, the episode has prompted renewed scrutiny of manufacturing practices, regulatory oversight, and the need for rapid, transparent communication in the face of potential threats to public health.
In the coming weeks, families and health officials alike will be watching closely for further developments, hoping for answers—and for the swift recovery of every infant affected by this rare and troubling outbreak.
