An outbreak of infant botulism linked to ByHeart powdered infant formula has ended, according to the US Centers for Disease Control and Prevention.

The final tally of victims comprises 28 confirmed cases and 20 probable cases from 17 states. No new cases have been added since December of 2025, and three previously reported suspected cases from 3 different states have been excluded from the totals.

Illnesses in this outbreak first began on December 24, 2023 and continued through November 29, 2025. The 48 victims ranged in age from 16 to 264 days old. All were hospitalized and treated with BabyBIG®. There were no deaths.

Outbreak cases were reported in Arizona (5), California (12), Idaho (2), Illinois (2), Kentucky (1), Massachusetts (2), Michigan (1), Minnesota (3), North Carolina (2), New Jersey (1), Oregon (3), Pennsylvania (1), Rhode Island (1), Texas (8), Virginia (1), Washington (2), and Wisconsin (1).

Epidemiological and laboratory analysis established ByHeart Whole Nutrition infant formula as the source of the illnesses. The company recalled all of its infant formula products on November 11, 2025.

Although the outbreak is officially over, the FDA‘s investigation into the root cause of the contamination continues.

In addition to the finding of Clostridium botulinum in opened and sealed cans of infant formula by the California Department of Pubic Health, the New York State Department of Health, and the company itself, the FDA recovered the pathogen from a sample of organic whole milk powder from Organic West Milk, which supplies the ingredient to ByHeart. The milk powder was processed for Organic West Milk by a Dairy Farmers of America (DFA) facility.

Spores of Clostridium botulinum are found in soil around the world, and the pathogen has been known to infect dairy herds. Although the FDA has not yet released any firm conclusions regarding the root cause of the contamination, if these heat-stable spores were in the raw organic milk delivered to DFA for processing, they would have been able to survive the heat of pasteurization and remain viable in the finished powdered milk.

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January 23, 2026

The US Food and Drug Administration (FDA) reported today that a sample of organic powdered whole milk used as an ingredient in ByHeart Whole Nutrition infant formula has tested positive for Clostridium botulinum.

The FDA report did not identify the source of the organic powdered whole milk ingredient.

The sample of powdered milk was collected by the FDA at a processor for a supplier to ByHeart, and was analyzed by the Wadsworth Center Laboratory of the New York State Department of Health. Whole genome sequencing (WGS) testing found that the strain recovered from the milk powder is a genetic match for the Clostridium botulinum strain isolated from an infant victims of the outbreak.

The strain found in the powdered milk also is a genetic match for the strain recovered from a closed container of ByHeart formula collected by the FDA during the course of its investigation.

According to an update released today by the CDC, the number of confirmed and suspect cases of infant botulism in this outbreak remains at 51 individuals in 19 states.

Information provided to eFoodAlert by a spokesperson for the California Department of Public Health (CDPH) confirms that the state’s Infant Botulism Prevention and Treatment Program, which is the sole supplier the BabyBIG antitoxin used in the US to treat infant botulism, has not received any reports of new cases linked to ByHeart since the CDC’s December 17, 2025, update.

The CDPH was the first agency to recognize that a multistate outbreak of infant botulism with a common product exposure was in progress, notifying the CDC on November 5, 2025. The CDC mobilized the multistate outbreak response two days later, on November 7th, according to the CDPH spokesperson.

On November 8th, in response to a recommendation from the FDA, ByHeart initiated a recall of two production batches of its Whole Nutrition infant formula. The company expanded its recall on November 11th to include all batches of ByHeart Whole Nutrition infant formula in cans and Anywhere Packs.

ByHeart’s manufacturing operation remains paused while the investigation continues. The company has been cooperating with the FDA investigation and also has engaged a third-party laboratory to conduct Clostridium botulinum testing of its multiple batches of finished products.

To date, testing conducted by ByHeart’s lab has confirmed the presence of Clostridium botulinum in six samples from two different batch codes, both of which were included in the company’s initial November 8, 2025, product recall. In addition, the CDPH recovered Clostridium botulinum from an opened container of one of those batch codes. A sealed container from a third batch code, collected by Arizona and analyzed under the FDA’s Laboratory Flexible Funding Model, also yielded Clostridium botulinum.

WARNING TO CONSUMERS: Although ByHeart recalled all of its product in November 2025, the FDA is still receiving reports from consumers who have found recalled product on store shelves. If you find a ByHeart product either at a retailer or on-line, do not purchase it. If you have any recalled product in your possession, do not use it.

Interested in learning more about food safety and the history of foodborne disease outbreaks and investigations?

Click on the link to listen to a short excerpt, then follow the buy links to add a digital, print or audio copy to your personal library.