Parents whose infants have suffered from botulism after consuming ByHeart baby formula are urgently seeking explanations regarding the handling of earlier cases. Health officials have confirmed contamination in the formula, leading to an expanded investigation into the illness’s potential sources and scope. This situation has raised significant concerns among families whose children were diagnosed with botulism prior to the officially recognized outbreak.
California health officials reported that six infants in the state received treatment for botulism after consuming ByHeart formula between November 2024 and June 2025. This was well before the outbreak that has since affected at least 31 infants across 15 states. The California Department of Public Health noted that there was insufficient evidence at the time to identify a common source for these earlier cases.
Families represented by food safety lawyer Bill Marler have indicated that at least five additional infants were treated for the rare and potentially fatal disease after ingesting ByHeart formula in late 2024 and early 2025. One notable case is that of Amy Mazziotti from Burbank, California, whose son, Hank, required treatment for botulism in March, just weeks after beginning to consume ByHeart formula. Similarly, Katie Connolly from Lafayette, California, reported that her daughter, M.C., was hospitalized and treated for botulism in April as a result of being fed ByHeart formula.
Both mothers were initially unaware of the potential link between their children’s illnesses and the formula. ByHeart officials have since confirmed that laboratory analyses of unopened formula samples revealed contamination with the bacteria responsible for infant botulism. Marler has indicated that at least three additional cases, predating the current outbreak, involved infants treated for botulism after consuming ByHeart formula.
The U.S. Centers for Disease Control and Prevention (CDC) acknowledged awareness of earlier illness reports but stated 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, highlighted the challenges in definitively linking earlier cases to the outbreak due to the time that has elapsed. She also noted that parents may lack records of product lot numbers or retain empty formula cans, making it difficult to establish a connection.
Connolly expressed her frustration, questioning why cases originating in August prompted an investigation while earlier cases were overlooked. Health officials explained that a strong association between ByHeart and infant botulism cases became clear only in recent weeks. Before the outbreak, no powdered infant formula in the U.S. had tested positive for the botulism-causing bacteria, and the number of cases had fallen within an expected range.
The discovery of the botulism-causing germ in a sample from a can of ByHeart formula, combined with the increased incidence of cases—especially on the East Coast and among very young infants—led to notifications to the CDC, the U.S. Food and Drug Administration (FDA), and the public.
Infant botulism, though rare, is a serious condition that occurs when babies ingest spores that germinate in the gut and produce a harmful toxin. The bacterium responsible is commonly found in the environment, making the source often difficult to trace. The California Infant Botulism Treatment and Prevention Program monitors botulism reports and the distribution of the only available treatment, an intravenous medication called BabyBIG.
Food safety experts, including former FDA deputy commissioner Frank Yiannas, advocate for including earlier cases in the outbreak count if the infants consumed ByHeart formula and received treatment for botulism. Yiannas questioned the rationale behind excluding these cases, emphasizing the need for comprehensive tracking.
As the investigation into the ByHeart infant formula botulism outbreak continues, parents are left grappling with the safety of the product they once trusted. Authorities are working diligently to determine the full extent of the contamination and to prevent further cases. The focus remains on thoroughly investigating the timeline of the outbreak and the potential sources of contamination within the ByHeart formula, while also providing necessary support and information to affected families.
