Recent news about avian influenza, commonly known as bird flu, affecting dairy cattle has raised questions among consumers about the safety of the milk supply. This article addresses these concerns directly, providing information on the safety of milk consumption amidst the ongoing situation.
Safety of Milk Consumption
Commercially available, pasteurized milk is widely considered safe for consumption, with health authorities confirming its safety. Pasteurization is a heating process that effectively inactivates viruses, including H5N1, and other harmful pathogens present in raw milk. This process involves heating milk to specific temperatures for a set duration, ensuring that any infectious agents are destroyed before the milk reaches consumers.
Scientific studies and regulatory assessments have consistently shown that standard pasteurization methods, such as High-Temperature, Short-Time (HTST) pasteurization (heating milk to 72°C for 15 seconds), are effective at eliminating the H5N1 virus. Extensive testing by the FDA on pasteurized dairy products, including milk, cheese, butter, and ice cream, has not detected any infectious H5N1 virus.
Raw, unpasteurized milk presents a different risk profile. The H5N1 virus has been detected in raw milk from infected cows, and animal studies indicate that consuming contaminated raw milk can lead to infection in mammals. Health organizations consistently advise against consuming raw milk due to its inherent risks of containing various pathogens, not limited to avian influenza.
Understanding H5N1 in Dairy Herds
The concern about bird flu and milk emerged after the highly pathogenic avian influenza (HPAI) A(H5N1) virus was first detected in dairy cattle in the United States in March 2024. Since then, the virus has been confirmed in dairy herds across numerous states, including California, Idaho, Colorado, Michigan, and Texas. This marked the first instance of H5N1 affecting cows, expanding the virus’s known host range.
Cows can become infected with H5N1 through various means, such as direct contact with infected wild birds or their droppings, or by consuming contaminated feed and water. Transmission between cows within a herd can also occur, and the infection primarily affects the mammary glands. Infected cows may exhibit symptoms like a decrease in appetite, reduced milk production, and milk that appears thickened or discolored.
The H5N1 virus has been found in raw milk collected from both clinically ill and asymptomatic dairy cattle. While the presence of the virus in raw milk from infected cows is a documented fact, pasteurization neutralizes this threat for consumers. Sporadic human infections have been reported in individuals with direct exposure to infected dairy cows, though there is no indication of sustained person-to-person transmission.
Official Recommendations for Consumers
Major health authorities, including the Centers for Disease Control and Prevention (CDC), the Food and Drug Administration (FDA), and the U.S. Department of Agriculture (USDA), consistently reinforce the safety of pasteurized milk and dairy products. They affirm that the commercial milk supply is safe to consume because pasteurization effectively kills the H5N1 virus. These agencies continue to monitor the situation closely to ensure public health.
Consumers are strongly advised to avoid drinking raw milk or consuming unpasteurized dairy products due to the potential presence of harmful pathogens, including H5N1. For products like cheese, consumers can check product labels to determine if raw milk was used in their production.
Beyond dairy, the CDC also recommends cooking poultry, eggs, and beef to their appropriate internal temperatures to eliminate bacteria and viruses, including avian influenza viruses. Following these guidelines helps ensure food safety and minimizes potential health risks.