Does Bird Flu Spread Through Food?

Can you please weigh in on bird flu in our food supply? Do I need to worry about milk, meat, etc.? My children especially love milk, and I’m concerned! Does the type of milk matter? Ultra-filtered, organic, or just milk?
—Anonymous

The background on this question is the current outbreak of bird flu — a particular strain of influenza (H5N1) — in dairy cows. We always worry when viruses move between species, especially into mammals, because of the possibility that the virus could move into us. H5N1 is a virulent flu strain, so this is a particular concern.

However: thus far, there is no reason for panic. There are 55 confirmed human cases (as of late November, 2024) and no documented evidence of person-to-person spread. The cases are almost certainly an under-count, but if the virus was spreading widely between people we would know, since it has been months.

People have been concerned about the possibility of flu virus spreading through milk. The FDA is also concerned about this and has been monitoring. The milk that most of us buy in stores is pasteurized, meaning it is treated to avoid contamination. The FDA has found evidence of viral fragments in milk but — very importantly — no evidence of any live virus. FDA scientists tried to grow virus from milk and were not able to. This is excellent evidence that pasteurization is doing what it needs to.

If you are buying pasteurized milk, any version of it is fine: organic, non-organic — they all run through the same process.

There is more concern if you are buying raw milk. Since raw milk does not go through a pasteurization process, bird flu virus can live in milk. In late November 2024, there was a voluntary recall on a particular raw milk brand which was found to have bird flu virus in it. There is no concrete evidence that anyone was sickened by this, but the CDC is investigating.

In general, a lack of pasteurization makes raw milk a more significant disease risk. It is responsible for an outsize share of dairy-related food-borne illness, making pasteurized milk a safer option, even in the absence of bird flu.