Pasteurized Milk H5N1 Proteins: Safe to Consume
- Here's a breakdown of recent research regarding the presence of H5N1 influenza virus fragments in US milk supplies, and what it means for public health.
- * What: Fragments of the H5N1 influenza virus (genetic material and proteins) have been detected in pasteurized milk in the US.
- The ongoing H5N1 outbreak affecting dairy cows in the United States has led to the detection of viral components - proteins and genetic material - in commercially available...
H5N1 in Pasteurized Milk: No Increased Risk, Study Finds
Here’s a breakdown of recent research regarding the presence of H5N1 influenza virus fragments in US milk supplies, and what it means for public health.
The ongoing H5N1 outbreak affecting dairy cows in the United States has led to the detection of viral components – proteins and genetic material – in commercially available milk. However,a new study from St. Jude Children’s Research hospital offers reassuring news: these inactive viral pieces pose little to no health risk,provided the milk has been pasteurized.
Pasteurization is Key
The pasteurization process effectively kills the virus, preventing infection. The concern raised by researchers was weather repeated exposure to these inactive viral fragments could inadvertently “teach” the immune system to tolerate them. This phenomenon, known as oral tolerance, normally prevents the immune system from reacting to harmless substances in food. Though, if oral tolerance developed to flu proteins, it could possibly increase susceptibility to future influenza infections.
The Study: No Impact on Immunity
To investigate this possibility, researchers at St.Jude conducted experiments on mice. They fed mice either uncontaminated pasteurized milk or pasteurized milk containing H5N1 viral fragments for five days, mimicking human consumption patterns. Weeks later,the mice were exposed to a live H5N1 infection.
The results were clear: there was no difference in the progression of the infection between the two groups. As stated by corresponding author Stacey Schultz-Cherry,PhD:
“We found that consuming pasteurized milk multiple times,even if it has inactivated H5N1 virus,poses minimal health risks. We observed no benefit or detriment to subsequent influenza infection.”
First author Pamela Brigleb, PhD, further emphasized, “We found an influenza infection after repeated exposure to H5N1 virus in pasteurized milk was normal, with no adverse events. We saw no evidence of it worsening the disease.”
Unpasteurized Milk Remains a Risk
The study also highlighted the dangers of consuming unpasteurized milk. Mice exposed to unpasteurized milk infected with H5N1 quickly succumbed to the disease, confirming findings from other research groups. Brigleb noted, “we did see that if infected milk wasn’t fully pasteurized, that was still very pathogenic in our model. That highlights the importance of pasteurization.”
Key Takeaways:
* Pasteurization effectively eliminates the H5N1 virus in milk.
* Consuming pasteurized milk containing inactive H5N1 fragments does not appear to affect the immune system’s ability to fight off future influenza infections.
* Unpasteurized milk remains a meaningful health risk.
* Continued monitoring of the H5N1 outbreak in dairy cows is essential.
Table: Comparison of Outcomes in Mice
| Group | Milk Type | H5N1 Infection Outcome |
|---|---|---|
| Control | Uncontaminated Pasteurized | Normal |
| Experimental | Pasteurized with H5N1 | Normal |
| Control | Unpasteurized with H5N1 | Succumbed to Disease |
Source: Schultz-Cherry,S., Brigleb, P., et al. (2024). Pasteurized milk containing inactivated avian influenza virus