California Issues Raw Milk Recall After Detection of H5N1 Bird Flu Virus

The California Department of Public Health (CDPH) has issued a public health warning urging consumers to avoid a specific batch of raw milk produced by Raw Farm, LLC of Fresno County after the detection of the H5N1 bird flu virus. The affected lot, labeled with the code 20241109 and a Best By date of November 27, 2024, is being voluntarily recalled at the state's request. While no human illnesses have been reported, the recall is being made as a precaution. CDPH emphasizes that pasteurized milk remains safe for consumption, as the pasteurization process kills harmful pathogens, including the bird flu virus.¹

This warning follows the detection of H5N1 in a retail sample of raw milk, confirmed by the Santa Clara County Public Health Laboratory and the California Animal Health and Food Safety Laboratory System. CDPH continues to advise consumers to avoid raw milk and raw milk products due to the risk of foodborne illness.¹

Raw milk products are not pasteurized, making them more susceptible to carrying sickening pathogens, including Salmonella, E coli, Listeria, and in this case, the bird flu virus. This risk is highlighted by the recent Salmonella outbreak from July 2024 linked to raw milk in California, which sickened 165 people, the largest such outbreak in the US in a decade.²

California’s Response to Bird Flu

California has reported 29 confirmed human cases of bird flu since October, with all cases linked to direct contact with infected dairy cows. Although no cases have involved person-to-person transmission, the state is taking proactive steps to monitor and control the outbreak. The CDFA has increased raw milk testing, conducting inspections at dairies and bulk milk tanks. Testing of raw milk will now be conducted twice per week to further safeguard public health.¹

The state has also stepped up its efforts to educate the public and ensure that dairy workers are protected. Personal protective equipment (PPE) has been distributed to dairy farms, and workers who meet infected cows or raw milk are being instructed on safety protocols.¹

Consumer Safety and Precautions

As part of the state’s broader response to the bird flu outbreak, California has enhanced surveillance and biosecurity efforts in dairy farming. Research has shown that the highly pathogenic H5N1 virus can remain infectious on milking equipment surfaces for several hours. This underscores the risks associated with handling unpasteurized milk, highlighting the need for effective biosecurity measures to protect both consumers and farm workers.³

“We observed that the H5N1 cattle virus remained infectious in unpasteurized milk on stainless steel and rubber inflation lining after 1 hour, whereas infectious virus in PBS fell to below the limit of detection after 1 hour. That finding indicates that unpasteurized milk containing H5N1 virus remains infectious on materials within the milking unit,” according to researchers from the CDC.³

The milking process involves the automated collection of milk through clusters attached to cow teats. During the process, there can be splattering, which poses a risk of exposure to potentially infectious milk. Workers are at particular risk of encountering unpasteurized milk during manual steps, such as cleaning the teats before attaching the milking clusters. Ongoing research is focused on understanding the persistence of influenza viruses on milking equipment and how to better protect farm workers from potential exposure.³

References

1. CDPH. California Acts to Protect Public Health: ​CDPH Warns Against Drinking Single Lot of Raw Milk Following Bird Flu Detection; Secures Voluntary Recall​. Published November 24, 2024. Accessed November 26, 2024. https://www.cdph.ca.gov/Programs/OPA/Pages/NR24-039.aspx

2. Abene S. Outbreak Linked to Raw Milk from California Farm. July 17, 2024. Accessed November 26, 2024. https://www.contagionlive.com/view/outbreak-linked-to-raw-milk-from-california-farm

3. CDC. Sialic Acid Receptor Specificity in Mammary Gland of Dairy Cattle Infected with Highly Pathogenic Avian Influenza A(H5N1) Virus. Emerging Infectious Diseases. Volume 30, Number 7—July 2024. Accessed November 26, 2024. https://wwwnc.cdc.gov/eid/article/30/7/24-0689_articl