Marler Clark has been retained by 30 families whose infants consumed ByHeart formula. Some of these infants became ill in late 2024 and early to mid 2025.
States with illnesses: Arizona 5, California 12, Idaho 2, Illinois 2, Kentucky 1, Massachusetts 2, Maine 1, Michigan 1, Minnesota 3, North Carolina 2, New Jersey 1, Ohio 1, Oregon 4, Pennsylvania 1, Rhode Island 1, Texas 8, Virginia 1, Washington 2 and Wisconsin 1.
The FDA and CDC, in collaboration with the California Department of Public Health (CDPH), Infant Botulism Treatment and Prevention Program (IBTPP), and other state and local partners, continue to investigate a multistate outbreak of infant botulism. Epidemiologic and laboratory data show that ByHeart Whole Nutrition infant formula might be contaminated with Clostridium botulinum, which is causing infant illness in multiple regions of the country.
ByHeart’s and FDA’s investigations into the root cause of the outbreak are ongoing, and at this time, FDA cannot rule out the possibility that contamination might have affected all ByHeart formula products. In response, CDC broadened the case definition to include any infant with botulism who was exposed to ByHeart formula at any time since the product’s release in March 2022. As of December 10, 2025, a total of 51 infants with suspected or confirmed infant botulism and confirmed exposure to ByHeart Whole Nutrition infant formula (various lots) have been reported from 19 states.
Previously, case counts included illnesses from August 1, 2025, onward. With the expanded definition, CDC and state partners identified 10 additional cases that occurred from December 2023 through July 2025. At this time, no cases have been identified between March 2022 and December 2023. All 10 are confirmed infant botulism cases with documented exposure to ByHeart formula.
Laboratory confirmation for some cases is ongoing. Illnesses started on dates ranging from December 24, 2023 to December 1, 2025. All 51 infants were hospitalized. No deaths have been reported to date. The infants range in age from 16 to 264 days and 22 (43%) are female.
State and local public health officials are interviewing caregivers about the foods the infants were fed in the month before they got sick. Fifty-one infants have been identified that were fed ByHeart Whole Nutrition powdered infant formula before getting sick.
FDA has not received reports of recalled formula being found on store shelves since November 26, 2025. All ByHeart infant formula products have been recalled, and these products should not be available for sale in stores or online. This includes all formula cans and single-serve “anywhere pack” sticks.
Additional testing by ByHeart, FDA, CDC, and state partners is underway, and results are expected in the coming weeks. Positive sample results for finished product testing will be included and updated in the Sample Results section.
FDA’s investigation is ongoing to determine the point of contamination. This advisory will be updated as information becomes available.
Useful Links
- CDC Outbreak Advisory
- Infant Botulism Treatment and Prevention ProgramExternal Link Disclaimer
- ByHeart Expanded Recall Announcement
Product Images
Sample Results
Product sampling and testing is being conducted by FDA, CDC, state partners, and ByHeart. Available information on positive samples is included below. This table will be updated as additional results become available or are shared with FDA.
Due to the large number of samples, only positive results are being reported here. The detection of Clostridium botulinum in infant formula is complex, and a negative test result does not rule out the presence of the bacteria in the product.
Parents and caregivers should not use any ByHeart infant formula, regardless of test results.
| Sample Collected/Analyzed by | Product | Test Result | Toxin Type |
| CDPH | Opened container of ByHeart Infant Formula (Batch No. 251131P2) | Positive | Type A |
| ByHeart | ByHeart Infant Formula (Batch/Batches Not Reported) | Positive | Type A |
| ByHeart | ByHeart Infant Formula (Batch/Batches Not Reported) | Positive | Type A |
| ByHeart | ByHeart Infant Formula (Batch/Batches Not Reported) | Positive | Type A |
| ByHeart | ByHeart Infant Formula (Batch/Batches Not Reported) | Positive | Type A |
| ByHeart | ByHeart Infant Formula (Batch/Batches Not Reported) | Positive | Type A |
International Distribution
The ByHeart infant formula recall impacts markets outside the United States. Customer information provided by Amazon shows that a limited quantity of recalled ByHeart infant formula was distributed to Argentina, Brazil, Brunei, Canada, Chile, China, Colombia, Ecuador, Egypt, Hong Kong, Israel, Jamaica, Japan, Republic of Korea, Peru, Philippines, Romania, Singapore, South Africa, Thailand, and the British Virgin Islands.
Consumers worldwide should not use any ByHeart brand infant formula as all ByHeart products are included in this recall.
What is Botulism?
Botulism is a rare, life-threatening paralytic illness caused by neurotoxins produced by an anaerobic, gram-positive, spore-forming bacterium, Clostridium botulinum.[1] Unlike Clostridium perfringens, which requires the ingestion of large numbers of viable cells to cause symptoms, the symptoms of botulism are caused by the ingestion of highly toxic, soluble exotoxins produced by C. botulinum while growing in foods.[2] These rod-shaped bacteria grow best under anaerobic (or, low oxygen), low-salt, and low-acid conditions.[3] Bacterial growth is inhibited by refrigeration below 4° C., heating above 121° C, and high water-activity or acidity.[4] And although the toxin is destroyed by heating to 85° C. for at least five minutes, the spores formed by the bacteria are not inactivated unless the food is heated under high pressure to 121° C. for at least twenty minutes.[5] C. botulinum bacteria and spores are widely distributed in nature, because they are indigenous to soils and waters.[6] They occur in both cultivated and forest soils, bottom sediment of streams, lakes, and coastal waters, in the intestinal tracts of fish and mammals, and in the gills and viscera of crabs and other shellfish.[7]
The incidence of foodborne botulism is extremely low.[8] Nonetheless, the extreme danger posed by the bacteria has required that “intensive surveillance is maintained for botulism cases in the United States, and every case is treated as a public health emergency.”[9] This danger includes a mortality rate of up to 65% when victims are not treated immediately and properly.[10] Most of the botulism events[11] that are reported annually in the United States are associated with home-canned foods that have not been safely processed.[12] Occasionally, though, commercially-processed foods are implicated as the source of a botulism events, including sausages, beef stew, canned vegetables, and seafood products.[13]
Symptoms of Botulism
After their ingestion, botulinum neurotoxins are absorbed primarily in the duodenum and jejunum, pass into the bloodstream, and travel to synapses in the nervous system.[14] There, the neurotoxins cause flaccid paralysis by preventing the release of acetylcholine, a neurotransmitter, at neuromuscular junctions, thereby preventing motor-fiber stimulation.[15]The flaccid paralysis progresses symmetrically downward, usually beginning with the eyes and face before moving to the throat, chest, and extremities.[16] When the diaphragm and chest muscles become fully involved, respiration is inhibited and, unless the patient is ventilated, death from asphyxia results.[17]
Classic symptoms of botulism include nausea, vomiting, fatigue, dizziness, double vision, drooping eyelids, slurred speech, difficulty swallowing, dryness of skin, mouth, and throat, lack of fever, muscle weakness, and paralysis.[18] Infants with botulism appear lethargic, feed poorly, are constipated, and have a weak cry and poor muscle tone.[19] Throughout all such symptoms, the victims are fully alert and the results of sensory examination are normal.[20]
In foodborne botulism cases, symptoms usually begin anywhere between 12 and 72 hours after the ingestion of toxin-containing food.[21] Longer incubation periods—up to 10 days—are not unknown, however. The duration of the illness is from 1 to 10 (or more) days, depending on host-resistance, the amount of toxin ingested, and other factors.[22] Full recovery often takes from weeks to months.[23] And, as earlier indicated, mortality rate can be from 30% to 65%, with rates generally lower in European countries than in the United States.[24]
Detection and Treatment of Botulism
Although botulism can be diagnosed based on clinical symptoms, its differentiation from other diseases is often difficult—especially in the absence of other known persons affected by the condition.[25] Once suspected, the most direct and effective way to confirm the diagnosis of botulism in the laboratory is testing for the presence of the botulinum toxin in the serum, stool, or gastric secretions of the patient.[26] The food consumed by the patient can also be tested for the presence of toxins.[27] Currently, the most sensitive and widely used method for the detection of the toxins is the mouse neutralization test, which involves injecting serum into mice and looking for signs of botulism.[28] This test typically takes 48 hours, while the direct culturing of specimens takes 5-7 days.[29] Some cases of botulism may go undiagnosed because symptoms are transient or mild, or are misdiagnosed as Guillain-Barre Syndrome.[30]
If diagnosed early, foodborne botulism can be treated with an antitoxin that blocks the action of toxin circulating in the blood.[31] This can prevent patients from worsening, but recovery still takes many weeks.[32] The mainstay of therapy is supportive treatment in intensive care, and mechanical ventilation in case of respiratory failure, which is common.[33]
Long-Term and Permanent Injury
Although a minority of botulism patients eventually recover their pre-infection health, the majority do not. For those who fully recover, the greatest improvement in muscle strength occurs in the first three months after the acute phase of illness.[34] The outside limit for such improvement appears, however, to be one year.[35] Consequently, physical limitations that still exist beyond the one-year mark are more probably than not permanent. Recovery from acute botulism symptoms may also be followed by persistent psychological dysfunction that may require intervention.[36]
According to a recently-published study that tracked the long-term outcomes of 217 cases of botulism, a large majority of patients reported “significant health, functional, and psychosocial limitations that are likely the consequences of the illness.”[37] These limitations included: fatigue, weakness, dizziness, dry mouth, and difficulty lifting things. The victims also reported difficulty breathing caused by moderate exertions, such as walking or lifting heavy items. They were also more likely to have limitations in vigorous activities, like running or playing sports, climbing up three flights of stairs, or carrying groceries. Summarizing its finding, the study concluded that:
Even several years after acute illness, patients who had botulism were more likely than control subjects to experience fatigue, generalized weakness, dizziness, dry mouth, difficulty lifting things, and difficulty breathing caused by moderate exertion….In addition, patients…reported worse overall psycho-social status than did control subjects, with patients being significantly less likely to report feeling happy, calm and peaceful, or full of pep.[38]
There is, as a result, no question that the damaging effects of botulism are life-long.
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[1] See J. Sobel, et al., Foodborne Botulism in the United States, 1990-2000, Emerging Infectious Diseases, Vol. 10, No. 9, at 1606 (Sept. 2004).
[2] James M. Jay, MODERN FOOD MICROBIOLOGY, 466 (6th Ed. 2000)
[3] Id. at 469-71; see also Sobel, supra note 2, at 1606.
[4] Sobel, supra note 2, at 1606.
[5] Id.
[6] Jay, supra note 3, at 467-69. See also, generally H. Houschild, Clostridium Botulinum, in FOODBORNE BACTERIAL PATHOGENS, at 112-89 (M. Doyle Ed. 1989)
[7] Jay, supra note 3, at 467-69.
[8] Sobel, supra note 2, at 1607-09; Jay, supra note 3, at 472-76.
[9] Sobel, supra note 2, at 1606-07 (also noting that the CDC maintains a 24-hour clinical consultation and emergency antitoxin release service).
[10] Jay, supra note 3, at 474.
[11] With botulism, the broader term “event” is used to encompass both outbreaks—i.e., two or more cases of botulism caused by a common-source, as well as individual (or sporadic) cases.
[12] Sobel, supra note 2, at 1610; Jay, supra note 3, at 474.
[13] Id.
[14] Thomas P. Bleck, Clostridium botulinum (Botulism), in MANDELL, DOUGLAS AND BENNETT’S PRINCIPLES AND PRACTICE OF INFECTIOUS DISEASE 2543, 2544 (5th ed. 2000).
[15] Id.; Sobel, supra note 2, at 1606.
[16] Bleck, supra note 15, at 2545; see also BOTULISM FACT SHEET, National Agricultural Bio-Security Center, Kansas State University, online at http://nabc.ksu.edu/content/factsheets/category/Botulism#f26
[17] Bleck, supra note 15, at 2545; Sobel, supra note 2, at 1606.
[18] Sobel, supra note 2, at 1606; Jay, supra note 3, at 474.
[19] Jay, supra note 3, at 476-77.
[20] Sobel, supra note 2, at 1606.
[21] Jay, supra note 3, at 474.
[22] Id.
[23] R. Shapiro, et al., Botulism in the United States: A Clinical and Epidemiologic Review, Ann. Intern. Med. 1998; 129:221-28.
[24] Jay, supra note 3, at 474.
[25] Bleck, supra note 15, at 2546 (noting that “botulism has a limited differential diagnosis”).
[26] Sobel, supra note 2, at 1607; see also FDA/CFSAN Bad Bug Book, Clostridium Botulinum, available at http://vm.cfsan.fda.gov/~mow/chap2.html
[27] Id.
[28] Bleck, supra note 15, at 2546. See also, e.g. MMWWR, supra note 1, at 2 (“CDC detected botulinum toxin Type A by mouse bioassay in the man’s serum sample”).
[29] Bad Bug Book, supra note at 25.
[30] Sobel, supra note 2, at 1606; Shapiro, supra note 23, at 223.
[31] Jay, supra note 3, at 474; Sobel, supra note 2, at 1606.
[32] Id.; Bleck, supra note 15, at 2546-67.
[33] Sobel, supra note 2, at 1606.
[34] Bleck, supra note 15, at 2547. See also P. Wilcox, et al., Recovery of Ventilatory and Upper Airway Muscles and Exercise Performance After Type-A Botulism, Chest, 98:620-26 (1990); J. Mann, et al., Patient Recovery From Type-A Botulism: Morbidity Assessment Following a Large Outbreak, Am. J. Public Health, 71 (3):266-69 (Mar. 1981).
[35] Id.
[36] Bleck, supra note 15, at 2547. See also F. Cohen, et al., Physical and Psychosocial Health Status 3 Years After Catastrophic Illness—Botulism, Issues Mental Health Nurs., 9:387098 (1988)
[37] S. Gottlieb, et al., Long-Term Outcomes of 217 Botulism Cases in the Republic of Georgia, Clin. Infectious Disease, 45: 174-80, at 180 (220&).
[38] Id. at 179.
Botulism: Marler Clark, The Food Safety Law Firm, is the nation’s leading law firm representing victims of Botulismoutbreaks. The Botulism lawyers of Marler Clark have represented thousands of victims of Botulism and other foodborne illness outbreaks and have recovered over $900 million for clients. Marler Clark is the only law firm in the nation with a practice focused exclusively on foodborne illness litigation. Our Botulism lawyers have litigated Botulism cases stemming from outbreaks traced to carrot juice, pesto, cheese and chili.
If you or a family member became ill with Botulism after consuming food and you’re interested in pursuing a legal claim, contact the Marler Clark Botulism attorneys for a free case evaluation.