U.S. health officials said FDA testing found botulism-causing bacteria in samples tied to ByHeart infant formula, including samples involving powdered whole milk used in the product. The agency said the tests matched bacteria found in a sealed can of formula and in samples of whole milk powder used to make the formula, though it cautioned that the findings were not conclusive and that the investigation is continuing.
In its work, FDA found botulism-causing bacteria type in two samples linked to ByHeart formula, officials said. The agency said bacteria in an unopened can of ByHeart formula matched a sample taken from a sick baby.
FDA also said that the bacteria in the sealed can matched contamination detected in samples of organic whole milk powder used to make ByHeart formula. FDA said the contamination was collected and tested by the company, and that its testing found a match to the germ associated with illness samples.
Separately, FDA testing found contamination in a sample of whole milk powder supplied to ByHeart, according to officials. FDA said the contamination in that supplied powder matched the germ found in a finished sample of the company’s formula.
The agency said the evidence is still not definitive and that the investigation continues “to determine the source of the contamination,” in a statement, according to the report. Neither FDA nor ByHeart named the supplier of the powdered whole milk.
ByHeart, in a statement, said the new finding “suggests that we are significantly closer to determining the root cause of the contamination,” the report said. FDA also said there was at the time no indication of a broader problem in the infant formula supply.
The investigation is tied to an outbreak that has sickened 51 babies in 19 states since December 2023, the report said. The problem was identified in November after officials in California, which supplies the sole treatment for infant botulism, detected a surge in cases in babies who consumed ByHeart formula, according to the report.
The CDC said no new cases in the outbreak had been identified since mid-December. ByHeart initially recalled two lots of formula and later expanded the recall to all products days afterward, the report said. Federal health officials later said they could not rule out contamination of all products made since the company launched in March 2022.
The report said this followed company testing announced in November that found six of 36 samples from three different lots contained the dangerous type of bacteria that causes infant botulism. Food safety experts told the AP that illnesses caused by botulism bacteria in infant formula are rare and that the size and scope of the ByHeart outbreak is unprecedented.
Advocates and legal representatives said the case also raises questions about testing practices. Sarah Sorscher, director of regulatory affairs for the Center for Science in the Public Interest, said in the report that FDA has not announced a plan to do testing and that “that’s what we really want to see them do,” adding that raw-material and finished-formula testing should be required.
Bill Marler, a Seattle food safety lawyer who represents more than 30 families of babies who fell ill, said even if contamination were traced to a milk supplier, ByHeart would still be responsible for the harm caused by its product. Marler said “Just because they are able to point the finger at dried powder as the ingredient that may have been contaminated, it doesn’t take any of the legal or moral responsibility away from ByHeart,” the report said.
ByHeart previously accounted for about 1% of the U.S. infant formula market and sold about 200,000 cans of the product per month, according to the report. The formula was marketed as an option close to human breast milk and using “organic, grass-fed whole milk,” and the report said some parents chose it, including because it cost about $42 per can and because of its touted health benefits.