Cows’ Milk, Bird Flu, & You

When it comes to dairy products, generally speaking, fermented ones (such as most cheeses and yogurts) are considered healthy in moderation, and unfermented ones have their pros and cons that can be argued and quibbled “until the cows come home”. We gave a broad overview, here:

Is Dairy Scary?

Furthermore, you may recall that there’s some controversy/dissent about when human babies can have cows’ milk:

When can my baby drink cow’s milk? It’s sooner than you think

So, what about bird flu now?

Earlier this year, the information from the dairy industry was that it was nothing to be worried about for the time being:

Bird Flu Is Bad for Poultry and Dairy Cows. It’s Not a Dire Threat for Most of Us — Yet.

More recently, the latest science has found:

❝We found a first-order decay rate constant of −2.05 day^–1 equivalent to a T₉₉ of 2.3 days. Viral RNA remained detectable for at least 57 days with no degradation. Pasteurization (63 °C for 30 min) reduced infectious virus to undetectable levels and reduced viral RNA concentrations, but reduction was less than 1 log₁₀.

The prolonged persistence of viral RNA in both raw and pasteurized milk has implications for food safety assessments and environmental surveillance❞

You can find the study here:

Infectivity and Persistence of Influenza A Virus in Raw Milk

In short: raw milk keeps the infectious virus; pasteurization appears to render it uninfectious, though viral RNA remains present.

This is relevant, because of the bird flu virus being found in milk:

World Health Organization | H5N1 strain of bird flu found in milk

To this end, a moratorium has been placed on the sale of raw milk, first by the California Dept of Public Health (following an outbreak in California):

California halts sales of raw milk due to bird flu virus contamination

And then, functionally, by the USDA, though rather than an outright ban, it’s requiring testing for the virus:

USDA orders testing of milk supply for presence of bird flu virus

So, is pasteurized milk safe?

The official answer to this, per the FDA, is… Honestly, a lot of hand-wringing and shrugging. What we do know is:

• the bird flu virus has been found in pasteurized milk too
• the test for this is very sensitive, and has the extra strength/weakness that viral fragments will flag it as a positive
• it is assumed that the virus was inactivated by the pasteurization process
• it could, however, have been the entire virus, the test simply does not tell us which

In the FDA’s own words:

❝The pasteurization process has served public health well for more than 100 years. Even if the virus is detected in raw milk, pasteurization is generally expected to eliminate pathogens to a level that does not pose a risk to consumer health❞

So, there we have it: the FDA does not have a reassurance exactly, but it does have a general expectation.

Source: US Officials: Bird flu viral fragments found in pasteurized milk

Want to know more?

You might like this mythbusting edition we did a little while back:

Pasteurization: What It Does And Doesn’t Do ← this is about its effect on risks and nutrients

Take care!