The Bird Flu and the Safety of Milk Supply in the United States
Researchers at Rocky Mountain Laboratories conducted a study on the safety of milk supply in the United States in relation to the Bird Flu virus. They found that even after undergoing a regular pasteurization process, there were still minimal amounts of infectious virus present in raw milk samples contaminated with high levels of the Bird Flu virus.
The study, published in NEJM, emphasized that these findings should not be used to draw conclusions about the safety of the milk supply in the United States as the experiments were conducted in a laboratory setting. The researchers explained that raw milk from cows infected with H5N1 Bird Flu may have a different composition or contain virus within the cells, which could affect the efficacy of heat treatment.
During March, it was discovered that dairy cows in the United States were infected with the Bird Flu. The Food and Drug Administration (FDA) conducted an investigation and found that approximately one fifth of the milk supply in the country contained traces of the virus even after pasteurization. However, the FDA maintains that pasteurized milk is still safe for consumption.
In the study, the researchers used virus isolated from a mountain lion’s lungs and mixed it with raw, unpasteurized cow’s milk. The samples were then subjected to heat treatment at different temperatures and durations. One of the samples, treated at 72 degrees Celsius for twenty seconds, still contained extremely small amounts of infectious virus.
The researchers concluded that there is a potential for a detectable quantity of H5N1 virus to remain infectious in milk after 15 seconds at 72 degrees Celsius if the initial virus levels were high enough. However, they noted that this finding was possible because the initial viral levels were appropriately high before the experiment began.
On the other hand, treatment at 63 degrees Celsius for 2.5 minutes resulted in a significant reduction in infectious Bird Flu virus. This suggests that the standard industry pasteurization process, which takes 30 minutes at that temperature, would be effective in eliminating infectious viruses.
The researchers acknowledged that the conditions of their experiment differed from large-scale industrial pasteurization operations for raw milk. They recommended replicating their findings using commercial pasteurization equipment and direct measurements of infected milk.
It is still unknown whether consuming milk with active H5N1 virus could potentially cause illness in humans. Further research is needed to understand the potential risks associated with consuming milk contaminated with the Bird Flu virus.
In conclusion, while this study highlights the presence of infectious Bird Flu virus in raw milk samples even after pasteurization, it is important to note that the safety of milk supply in the United States is monitored by regulatory agencies like the FDA. Pasteurized milk remains the recommended and safe option for consumption.