Parents of several infants who drank ByHeart powdered formula say their babies were diagnosed and treated for infant botulism months before public health authorities identified a large cluster of cases beginning Aug. 1. California officials confirmed six infants who consumed ByHeart were treated for botulism between Nov. 2024 and June 2025, while investigators now link at least 31 cases across 15 states to a larger outbreak since August. Families and their attorney say additional pre‑August illnesses deserve investigation; federal officials say they are prioritizing the recent surge while continuing to note earlier reports. ByHeart issued a nationwide recall on Nov. 11 after tests on some unopened product found the bacteria that can cause infant botulism.
Key Takeaways
- At least 31 infant botulism cases have been documented since Aug. 1 across 15 states, according to public reports and health agencies.
- California public health investigators confirmed six infants who consumed ByHeart formula were treated for botulism between Nov. 2024 and June 2025.
- Parents of at least five infants — including cases in March and April 2025 — report treatment for botulism after feeding ByHeart formula, per families and their attorney.
- ByHeart recalled all products nationwide on Nov. 11, 2025, after some unopened cans tested positive for bacteria linked to infant botulism.
- Infant botulism is rare in the U.S.; fewer than 200 cases are reported annually, and standard treatment includes the antitoxin BabyBIG.
- Investigators say linking earlier cases to the current outbreak is complicated by time elapsed and missing lot numbers or empty cans.
Background
Infant botulism results when infants ingest Clostridium botulinum spores that germinate in the immature gut and produce toxin. Cases are uncommon nationwide — typically under 200 per year — and historically have been associated with environmental exposure or known sources such as honey. Powdered infant formula has not previously tested positive for the bacterium implicated in these illnesses in U.S. records, making the current situation unusual for public health teams.
ByHeart is a small manufacturer whose market share is under 1 percent of U.S. formula sales, but its products became the focus of investigations after a cluster of cases on the East Coast beginning in August involved a toxin type rarely seen there. State and federal agencies, including the California Department of Public Health, the CDC and the FDA, have coordinated testing and case surveillance while the company issued a recall in November.
Main Event
Beginning in August and continuing through October, public health authorities noticed an atypical rise in infant botulism cases and an unusual geographic pattern, prompting expanded laboratory and epidemiologic work. Laboratory analysis later identified the bacterium in some previously unopened ByHeart cans, triggering a nationwide recall on Nov. 11. Officials say the positive tests and the cluster of recent cases established a strong signal linking the product to illness.
Separately, parents and attorney Bill Marler shared reports of at least five infants who were treated for botulism months earlier, with illnesses occurring in late 2024 and spring 2025. California officials confirmed six ByHeart‑exposed infants received treatment between Nov. 2024 and June 2025, but said at the time there was not enough evidence to identify a single common source. The state has said it still cannot definitively connect pre‑Aug. 1 cases to the larger outbreak.
Families say the early diagnoses were unexpected and that many did not retain lot information or empty cans, complicating retrospective links. In some earlier investigations, tests of open cans used in households did not detect the bacterium. Federal investigators say they are aware of earlier reports but are focused on understanding the large increase in cases that began in August.
Analysis & Implications
If pre‑August cases are part of the same contamination event, the timeline would broaden the window for when contaminated product entered the supply chain and raise questions about inspection, lot tracing and distribution pathways. Public health investigators rely on lot numbers, retained containers and prompt reporting to connect cases to manufactured products; the absence of those data makes retrospective attribution difficult. Legally, linking earlier cases could influence liability and compensation for affected families and prompt broader regulatory scrutiny of powdered formula production controls.
For clinicians and hospitals, a wider recognition that formula can be a vehicle for infant botulism would likely lead to heightened surveillance for the disease in infants with feeding difficulties, constipation or neuromuscular weakness. Public health messaging may shift to emphasize safe handling of powdered formula and rapid reporting of suspected cases. Supply chain implications could pressure manufacturers to adopt additional environmental testing and stricter contamination prevention measures.
Internationally, detection of contaminated powdered formula in the United States is likely to draw attention from regulators in other countries that import U.S.-made products or follow U.S. standards. The incident may prompt global reassessment of powdered formula testing protocols and supply chain audits, especially for manufacturers with small market share but broad distribution.
Comparison & Data
| Period | Reported ByHeart‑exposed Cases | Notable Events |
|---|---|---|
| Nov 2024–Jun 2025 | 6 infants (California, treated) | State reports of individual treated infants; insufficient evidence then for common source |
| Aug 1–Oct 2025 | At least 31 infants (15 states) | Cluster identified; rare toxin type on East Coast; several cans later tested positive |
| Nov 11, 2025 | — | ByHeart issued nationwide recall after positive lab tests on unopened cans |
The small table summarizes confirmed and reported timelines tied to ByHeart‑exposed infants and key milestones in the investigation. Public data show a modest number of earlier California cases that predate the August cluster and a later sharp increase that drew national attention. The lack of container retention and lot tracking for some earlier patients reduces the ability to make definitive epidemiologic links.
Reactions & Quotes
Parents whose infants were hospitalized months before the outbreak say they were left with unanswered questions and felt their cases were overlooked when public attention focused on the later surge. They emphasize the emotional and medical toll on families and seek transparency about any data that could explain how their children became ill.
“This cannot be a coincidence,”
Amy Mazziotti (parent)
Health officials describe a prioritization of the large increase after Aug. 1 while acknowledging earlier reports remain part of their awareness. They note that linking older cases is hampered when product identifiers are not available.
“Right now, we’re focusing on this large increase,”
Dr. Jennifer Cope (CDC)
Food safety experts and advocates pressed for inclusion of earlier cases in the outbreak tally if exposure to ByHeart can be established, arguing that comprehensive accounting aids public health response and justice for affected families.
“They should be included,”
Frank Yiannas (food policy expert)
Unconfirmed
- Whether the Nov. 2024–Jun. 2025 California cases are epidemiologically linked to the Aug. 1 outbreak remains unconfirmed due to missing lot information and elapsed time.
- Not all cans opened in households of earlier cases tested positive; missing laboratory evidence prevents definitive attribution of those illnesses to ByHeart product.
Bottom Line
The emergence of a sizable cluster of infant botulism cases linked to a specific powdered formula brand is unprecedented in recent U.S. public health experience and has prompted a nationwide recall and multiple agency investigations. Families with earlier illnesses argue those cases should be counted if exposure is confirmed; investigators say data limitations make retrospective linking challenging but do not rule out connection.
For parents and clinicians, the immediate priorities are ensuring exposed infants receive timely evaluation and treatment, improving product traceability, and strengthening surveillance for rare but severe illnesses. In the months ahead, laboratory testing, lot tracing and transparent reporting will determine whether the earlier reported cases broaden the outbreak timeline and shape regulatory and legal outcomes.
Sources
- The Associated Press — (news)
- Centers for Disease Control and Prevention (CDC) — (official public health guidance)
- California Department of Public Health — (state public health agency)
- Marler Clark / Bill Marler — (law firm representing families)