The U.S. Department of Agriculture (USDA) is beginning to test the country's milk supply for H5N1, the avian influenza virus, following concerns about the spread of the virus through dairy products.
With an increase in bird flu cases over the past year, the virus has been found to spread among cows and to farm workers, raising questions about the safety of consuming milk and related dairy products.
Why is Milk Being Tested?
Health officials are now testing milk in large storage tanks at dairy processing facilities before pasteurization. These tanks typically contain milk from multiple dairy farms, making it an essential point for early detection. Farmers and processors will also be required to provide milk samples when requested, helping authorities track and manage potential outbreaks. The primary goal of these tests is to protect farm workers and trace the virus's movement between dairy herds. It's important to note, however, that this testing does not apply to raw milk farms, which may be regulated differently across states.
How Much Virus is in Raw Milk?
When cows are infected with bird flu, their milk contains high concentrations of the virus, which is much higher than in other fluids such as blood or nasal swabs. This makes milk a key pathway for transmission, both between cows and from cows to humans. The virus can survive in refrigerated, unpasteurized milk for up to five weeks, according to research. A recent case saw a large raw milk supplier in California recall milk and cream after bird flu was detected in samples, leading to a quarantine of the farm.
Is It Safe to Drink Raw Milk?
At present, no human cases of bird flu have been linked to consuming raw milk. However, the possibility remains uncertain, given the high viral concentrations in raw milk. Dr. Keith Poulsen, director of the Wisconsin Veterinary Diagnostic Laboratory, cautioned against taking the risk. While some animals have died after consuming contaminated raw milk, workers handling raw milk have been more likely to contract the virus due to direct exposure, such as handling or splashing milk into their eyes. Although the virus has caused only mild symptoms in these workers, its effects on children, older adults, and immunocompromised individuals remain unclear.
In addition, the FDA has long warned against drinking raw milk due to the potential for bacterial contamination, including pathogens like salmonella and listeria, which pose serious risks to vulnerable populations.
What About Other Raw Milk Products?
The risks extend beyond milk itself to other dairy products made from raw milk, such as yogurt and kefir. It's unclear whether fermentation processes in these products reduce the virus's presence, but they can still harbor other harmful bacteria. The California Department of Public Health has advised against consuming any raw milk products, including cheese and kefir, from affected producers.
Is Pasteurized Milk Safe?
Yes, pasteurized milk remains safe to consume. Pasteurization, which involves heating milk to eliminate harmful microorganisms, has been shown to inactivate the bird flu virus. Health experts emphasize that pasteurization is crucial not only for preventing avian influenza but also for reducing other health risks from bacterial contamination in milk.
Can Bird Flu Affect Pets?
Pets, particularly cats and dogs, can also fall ill from consuming raw milk contaminated with bird flu. There have been instances of pets getting severely ill or even dying after drinking contaminated milk, particularly on farms. Health officials warn against feeding pets unpasteurized products like milk or kefir, as this poses a significant risk to their health.
While pasteurized milk is considered safe, raw milk and related products pose potential health risks due to the bird flu virus and other pathogens. It's crucial to follow safety guidelines and stay informed about the latest health advisories.
