Parents are seeking answers regarding a troubling series of botulism cases linked to ByHeart baby formula. Although health officials have confirmed contamination in the formula, earlier cases have raised questions about why they were not investigated alongside the current outbreak. The situation has prompted an extensive investigation into the potential sources and scale of the illness.
Health officials in California revealed that six infants in the state were treated for botulism after consuming ByHeart formula between November 2024 and June 2025. This timeline predates the recognized outbreak, which has so far affected at least 31 infants across 15 states. As the investigation unfolds, parents whose children fell ill prior to the outbreak are voicing their concerns about the handling of these earlier cases.
Reports indicate that at least five additional infants were treated for botulism after ingesting ByHeart formula in late 2024 and early 2025. One notable case involves Amy Mazziotti from Burbank, California, whose son Hank was hospitalized in March after starting on ByHeart formula. Similarly, Katie Connolly from Lafayette, California, reported that her daughter, M.C., required hospitalization in April, also linked to ByHeart formula.
ByHeart officials have confirmed that laboratory analyses of unopened formula samples revealed the presence of the bacteria responsible for infant botulism. According to food safety attorney Bill Marler, at least three additional cases predating the outbreak have involved infants treated for botulism after consuming ByHeart formula.
The U.S. Centers for Disease Control and Prevention (CDC) acknowledged that they were aware of earlier illness reports. However, they emphasized that current efforts are focused on understanding the recent surge in infections documented since August 1, 2025. Dr. Jennifer Cope, who leads the CDC investigation, noted that while earlier cases may be connected, the priority is the recent spike in cases.
Parents like Connolly have expressed frustration over the situation, questioning why cases beginning in August prompted an investigation when earlier ones did not. Health officials explained that the strong link between ByHeart and infant botulism cases became increasingly clear only in recent weeks. Prior to the outbreak, no powdered infant formula in the U.S. had tested positive for the bacteria, and the number of cases had remained within expected ranges.
The discovery of the bacteria in a sample from ByHeart formula, coupled with a rise in cases—especially among very young infants—prompted notifications to the CDC, the U.S. Food and Drug Administration, and the public. Infant botulism is a rare but serious condition that occurs when babies ingest spores that germinate in the gut, producing a potent toxin. The bacterium responsible is commonly found in the environment, making tracking its source challenging.
The California Infant Botulism Treatment and Prevention Program monitors botulism reports and the distribution of the only available treatment, an intravenous medication known as BabyBIG. Food safety experts, including former FDA deputy commissioner Frank Yiannas, advocate for including earlier cases in the outbreak count if infants consumed ByHeart formula and received treatment for botulism. His comments underscore the need for a thorough investigation into all relevant cases.
As parents navigate the trauma of their children’s illnesses, they are left questioning the safety of the product they once trusted. The ongoing investigation aims to determine the full scope of contamination and prevent further cases. Authorities are committed to examining the timeline of the outbreak and identifying potential sources of contamination in ByHeart formula while providing support and information to affected families.
