FILE – Stephen Dexter holds a container of ByHeart infant formula, which ByHeart recently recalled, in Flagstaff, Arizona, Wednesday, Nov. 12, 2025.
Cheyanne Mumphrey/AP
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Cheyanne Mumphrey/AP
Federal health officials on Wednesday expanded information about the infant botulism outbreak linked to the ByHeart infant formula recall to include all illnesses reported since the company began production in March 2022.
The US Food and Drug Administration said investigators “cannot rule out the possibility that the contamination may have affected all ByHeart products ever manufactured.”
The outbreak is currently affecting at least 51 infants in 19 states. According to the US Centers for Disease Control and Prevention, the new case definition includes “any infant with botulism who was exposed to ByHeart formula at any time since the product was introduced.” The latest illness was reported on December 1.
There have been no deaths reported in the outbreak, which was declared on November 8.
Health officials previously said there have been 39 suspected or confirmed cases of infant botulism in 18 states since August. That's when the California Infant Botulism Treatment and Prevention Program reported an increase in the number of cases of treatment of infants who consumed ByHeart formula. An additional 12 cases were identified using the expanded definition, including two that occurred in the original timeline and 10 that occurred between December 2023 and July 2025.
ByHeart, a New York-based manufacturer of organic infant formula founded in 2016, issued a recall on November 11 for all of its products sold in the United States. The company, which has about 1% of the U.S. infant formula market, sold about 200,000 cans of the product each month.
The news that ByHeart products may have been contaminated for years upset Andy Galindo, whose 5-week-old daughter Rowan was hospitalized in December 2023 with infant botulism after drinking formula. Galindo, 36, of Redondo Beach, California, said she insisted on using ByHeart formula to supplement small amounts of breast milk because a lactation consultant recommended it as “very natural, very gentle and very good for babies.”
“It's a difficult question,” Galindo said. “If there is evidence that there were problems with their production and plant from the beginning, that's a problem and they really should be held accountable.”
Amy Mazziotti, 43, of Burbank, California, said her five-month-old son Hank became ill and was being treated for botulism in March, a few weeks after he started drinking ByHeart. Participating in the outbreak investigation “feels like a win for all of us,” she said Wednesday.
“I knew from the beginning that ByHeart was the reason Hank got sick, and to see these cases now being part of the investigation brings me to tears – a mixture of relief, gratitude and hope that the truth is finally out,” she said.
In a statement late Wednesday, ByHeart officials said the company is working with federal officials “to understand the full scope of the cases involved.”
“The new cases reported to the CDC and FDA will assist in the ByHeart investigation as we continue to search for the root cause of the infection,” the statement said.
Laboratory tests revealed infection
Last month, the FDA sent inspectors to ByHeart's factories in Allerton, Iowa, and Portland, Oregon, where the formula is manufactured and packaged. The agency has not released the results of these inspections.
The company previously said tests by an independent laboratory found that 36 samples from three different batches contained a type of bacteria that can cause infant botulism.
“We cannot rule out the risk that all ByHeart formulas in all product lots may be contaminated,” the company wrote on its website last month.
Those findings and discussions with the FDA prompted CDC officials to expand the outbreak, according to Dr. Jennifer Cope, the CDC scientist leading the investigation.
“It appears that the contamination persisted across all production runs, across batches, across batches of raw materials,” Cope said. “They couldn’t allocate individual lots over a period of time.”
Inspection documents showed ByHeart had pollution problems in the past.
In 2022, when ByHeart began producing infant formula, the company recalled five batches of infant formula after a sample at a packaging plant tested positive for a different microbe, cronobacter sakazakii. In 2023, the FDA sent the company a warning letter detailing “areas that still require corrective action.”
The ByHeart plant in Reading, Pennsylvania, closed in 2023, just before FDA inspectors discovered problems with mold, water leaks and insects, records show.
Infant botulism is rare.
Infant botulism is a rare disease that affects fewer than 200 infants in the United States each year. It occurs when infants ingest botulism bacteria, which produce spores that germinate in the intestines, creating a toxin that attacks the nervous system. Babies are vulnerable until about a year old because their gut microbiome is not mature enough to fight the toxin.
Infant formula has previously been linked to sporadic cases of illness, but research has shown that there have been no previous known outbreaks of infant botulism associated with powdered formula.
Symptoms can take up to 30 days to appear and may include constipation, poor diet, loss of head control, drooping eyelids and a flat facial expression. Babies may feel “floppy” and may have trouble swallowing or breathing.
The only treatment for infant botulism is known as BabyBIG, an intravenous drug prepared from the pooled blood plasma of adults immunized against botulism. The California Infant Botulism Program developed this product and is the only source worldwide.
The antibodies provided by BabyBIG are likely most effective within a month, although they may continue to circulate in the baby's body for several months, said Dr. Sharon Nachman, a pediatric infectious disease expert at Stony Brook Children's Hospital.
“The risk to the infant remains and families should not use this formula after it has been recalled,” Nachman said in an email.
The families of several children who were treated for botulism after drinking ByHeart formula have sued the company. The lawsuits filed in federal courts allege that the formula they fed their children was defective and ByHeart was negligent in marketing it. They seek financial payment for medical bills, emotional distress and other harm.









