The news on the safety of pasteurized dairy products following the detection of H5N1 in dairy cattle continues to be reassuring, with the FDA reporting yesterday that after analyzing nearly 300 retail mild samples they were unable to culture the virus in any of them.
Additionally the FDA reports being unable to detect H5N1 RNA in retail powdered infant formula and powdered milk products.
The big concern continues to be the consumption of `raw milk' or unpasteurized dairy products. And while there are laws on the books in most states to discourage the practice, there are enough loopholes that if someone really wants raw milk, they can generally find it.
Colorado was set to relax their strict laws on the sale of raw milk this week, but according to Food Safety News (see Colorado raw milk bill laid over to next year), the recent outbreak of H5N1 in dairy cattle has at least temporarily derailed those plans.
The `raw milk' movement in the United States continues to grow. A 2022 study published in the Journal of Food Protection reported that:
Results show that 4.4% of U.S. adults reported consuming raw milk at least once in the past year, with 1.6% reporting frequent consumption of raw milk (once per month or more often) and 1.0% reporting consumption once per week or more often.
Which suggests that several million people in the United States regularly consume raw milk, a practice that even without avian flu, carries a number of health risks.
First, the latest from the FDA, after which I'll have a bit more.
Ongoing Work to Ensure Continued Effectiveness of Federal-State Milk Safety System
What's New
May 1, 2024
The FDA is announcing an additional set of results from our national commercial milk sampling study underway in coordination with USDA. The study includes 297 total retail dairy samples. New preliminary results of egg inoculation tests on a second set of 201 quantitative polymerase chain reaction (qPCR)-positive retail dairy samples, including cottage cheese and sour cream, in addition to fluid milk, show that pasteurization is effective in inactivating HPAI.
This additional preliminary testing did not detect any live, infectious virus.
In addition to preliminary results released late last week on an initial set of 96 retail milk samples, these results reaffirm our assessment that the commercial milk supply is safe.
To ensure the safety of milk-derived products for our youngest populations, the FDA also tested samples of retail powdered infant formula and powdered milk products marketed as toddler formula. All qPCR results of formula testing were negative, indicating no detection of HPAI viral fragments or virus in powdered formula products so no further testing was required for these samples. The FDA is continuing to identify additional products that may be tested.
The FDA is also continuing to test samples of pooled raw milk that has been routed to pasteurization and processing for commercial use. This will be used as a basis to characterize potential virus levels that pasteurization may encounter – and will be used to inform studies to further validate pasteurization.
As this situation evolves, the FDA will continue to consider all ongoing scientific research related to the effectiveness of pasteurization for HPAI in bovine milk. We are also committed to continued surveillance of milk production, processing and pasteurization to help ensure the safety of the milk supply. Our state partners are integral to this process, and we are working with them on a continual basis. We will also continue working with our state co-regulators on managing this emerging disease.
The FDA continues to advise strongly against the consumption of raw milk and recommends that industry does not manufacture or sell raw milk or raw milk products.
To date the HPAI H5N1 in dairy cattle (and goats) has only been reported in the United States, but the B3.13 genotype has also been detected in wild birds, and has the potential to expand its geographic range via the major migratory flyways (see below).
Although these are primarily north-south conduits, and the most immediate threat would appear to be to Canada and Mexico, there are enough overlaps that lateral east and west movements are possible given enough time.
Canada has much stricter laws regarding unpasteurized dairy products, but in Mexico the consumption of raw milk (`leche bronca') is far more common than in the United States. In 2019 the USDA reported unpasteurized, raw milk accounts for between 5-10% of consumption in Mexico.
SENISICA published last week that (at least in commercial poultry) Mexico is free of avian influenza AH5N1 and AH5N2, but I'm seeing very little about testing of cattle, and milk in Mexico. Hopefully they are taking a more proactive stance than it appears on the surface.
While there are no guarantees that HPAI H5 will ever spark a pandemic, with each spillover into a mammalian host, the virus gets another chance the roll the genetic dice.
Something it does often enough without us giving it a helping hand.