Public Health officials warn against drinking raw milk due to risk of bird flu

May 10, 2024

SOLANO COUNTY - Public health officials in Solano and Yolo counties are advising residents to refrain from consuming raw milk or raw dairy products, such as raw-milk cheese, due to the recent detection of highly pathogenic avian influenza virus (H5N1), commonly known as bird flu, in dairy cows and their milk. 

Avian influenza has been spreading among wild birds worldwide since 2021, with subsequent infections identified in domestic poultry flocks and now in dairy cattle in the United States. Since March, avian influenza has been confirmed in 35 dairy herds across 9 states. Notably, raw milk from infected cows has been found to contain very high levels of the avian influenza virus.  

During the current dairy cow outbreak, one person is known to have been infected with avian influenza, a dairy worker in Texas who experienced mild symptoms and subsequently recovered. However, little testing has been done in people and workers may be reluctant to report symptoms.  

Dr. Aimee Sisson, Yolo County’s Public Health Officer, stressed the importance of avoiding raw milk consumption, stating, "Based on the risk of exposure to avian influenza, I strongly recommend that people not consume raw milk or dairy products at this time. Pasteurized milk and dairy products made from pasteurized milk remain safe to consume." 

Dr. Bela Matyas, Solano County Public Health Officer, added, “Besides the current concerns with H5N1 and unpasteurized milk, there are potentially other harmful germs in raw milk that have been proven to cause human disease before, including tuberculosis, brucellosis and gastrointestinal diseases. Pasteurized milk and dairy is healthy and safe. Why take the risk?” 

The U.S. Department of Agriculture (USDA) and the U.S. Food and Drug Administration (FDA) have conducted tests on pasteurized milk and dairy products from retail stores, revealing the presence of avian flu virus particles but no live virus. This underscores the effectiveness of pasteurization in inactivating avian influenza virus in milk.  

Not all milk sold in California is pasteurized. The sale of raw, unpasteurized milk is permitted in California, although health officials have long cautioned against its consumption due to associated health risks. Raw milk can harbor various pathogens capable of causing severe illness and death, including tuberculosis, salmonella, E. coli, and now, avian influenza virus.  

Rather than wait for people to contract avian influenza by consuming raw milk before issuing a warning, local health officials are acting based on preliminary data to warn about the potential for contracting avian influenza by consuming raw milk and milk products. The potential symptoms in humans who consume raw milk contaminated with avian influenza virus are unknown. On farms with cows infected with avian influenza, several cats that consumed raw milk developed severe neurological disease and died.  

For more information about raw milk safety, visit the U.S. Food and Drug Administration’s webpages at www.fda.gov/food/milk-guidance-documents-regulatory-information/questions-and-answers-regarding-milk-safety-during-highly-pathogenic-avian-influenza-hpai-outbreaks#rawmilkcheese, and www.fda.gov/food/resources-you-food/raw-milk, or visit the Centers for Disease Control and Prevention’s webpage at www.cdc.gov/foodsafety/rawmilk.