Formula-linked infant botulism outbreak prompts food safety questions

A botulism outbreak in US infants exposed to a particular brand of formula is highlighting the importance of food safety surveillance—and 2025 actions by the federal government that experts say are eroding the nation’s readiness to handle foodborne illness outbreaks.

The Infant Botulism Treatment and Prevention Program (IBTPP) within the California Department of Public Health (CDPH) saw an increase in requests for BabyBIG—the only FDA-approved treatment for infant botulism, which CDPH manufactures—and subsequently identified a common exposure among infants with botulism to ByHeart Whole Nutrition powdered infant formula, CDPH information officer Beth Deines said in a written statement.

On Nov. 8, ByHeart agreed to recall two lots of formula and expanded the recall on Nov. 11 to include all formula nationwide following a request from the US Food and Drug Administration (FDA). The agency is collaborating with the US Centers for Disease Control and Prevention (CDC), IBTPP, and state and local partners to investigate the outbreak, FDA spokesperson Emily Hilliard said in response to a request for comment. “The FDA has been in contact with the firm, and the FDA’s investigation is ongoing to determine the point of contamination,” she added. The CDC did not respond to a similar request.

Infants develop botulism from swallowing spores of the Clostridium botulinum bacteria, which colonize the large intestine and produce botulinum toxin. The toxin interferes with the transmission of nerve signals to muscles and can cause muscle weakness and difficulty breathing. It can be life-threatening if left untreated.

As of Nov. 14, 23 infants from 13 states who consumed ByHeart formula have received either a suspected or confirmed diagnosis for botulism. All infants, who range in age from 16 to 200 days, have been hospitalized and treated with BabyBIG; no deaths have been reported.

According to IBTPP data, a total of 84 US infants received treatment for botulism between Aug. 1 and Nov. 10, 36 of whom were exposed to formula. Of those 36, 15 (42%) ate ByHeart formula, despite ByHeart representing only about 1% of all infant formula sales in the US, according to the FDA.

“That is a very strong epidemiologic signal that the FDA was very concerned about,” says Susan Mayne, former director of the FDA’s Center for Food Safety and Applied Nutrition and current adjunct professor at the Yale School of Public Health. During outbreaks of foodborne illness, investigators from the FDA’s Coordinated Response and Evaluation Network team test facilities and food products to confirm such signals, and because they are deemed essential, they worked through the federal government shutdown, Mayne says.

However, she says some Trump administration policies have hindered efforts to prevent and monitor foodborne illness outbreaks. This summer, for instance, the federal-state collaboration known as the Foodborne Diseases Active Surveillance Network reduced the number of foodborne pathogens that participating states are required to monitor from eight to two (botulism was not among the eight). Earlier this year, the administration disbanded the National Advisory Committee on Microbiological Criteria for Foods, which, Mayne notes, was set to release a report on microbial contamination in infant formula.

Additionally, some food safety scientists and inspectors at the FDA were included in mass layoffs at the agency in February, though some were subsequently rehired.

Layoffs at CDC last month cut the agency’s entire Washington office, eliminating a vital line of communication from the CDC to congressional offices, says Sarah Sorscher, director of regulatory affairs at food safety watchdog Center for Science in the Public Interest. “For this outbreak, they would have sent out an alert and scheduled a briefing so members of Congress can know what’s going on,” she says of the Washington office. In their absence, “there’s no communication that can come directly from the teams investigating the outbreak.”

In 2022, a recall of contaminated formula and the ensuing shutdown of a major factory led to a nationwide formula shortage. Given ByHeart’s small market share, it’s highly unlikely we’ll now see a shortage, Mayne and Sorscher emphasize. Still, the ByHeart outbreak is a sign that the federal government should renew its efforts to prevent and mitigate this kind of food safety issue, they say.

“This really highlights that the administration needs to recognize the importance of protecting against microbial contamination in infant formula,” Mayne says.