Raw milk is often marketed as a wholesome, natural alternative to pasteurized dairy products. However, recent research reveals a concerning health risk associated with its consumption. A study conducted by Stanford University discovered that the influenza virus can survive in refrigerated raw milk for upto five days which is a potential health hazard to consumers.
Study Findings and Public Health Implications
The study's findings emerged amid heightened concerns about bird flu outbreaks affecting dairy cattle by raising fears of a potential new pandemic. Researchers highlighted that while raw milk enthusiasts believe in its nutritional superiority, its lack of heat treatment allows harmful pathogens including the flu virus to remain infectious.
Alexandria Boehm, senior author of the study and the Richard and Rhoda Goldman Professor of Environmental Studies at Stanford University emphasized the significance of their findings. “This work highlights the potential risk of avian influenza transmission through consumption of raw milk and the importance of milk pasteurization,” she stated.
Why Some Prefer Raw Milk
Despite the risks, more than 14 million Americans consume raw milk every year. Advocates argue that raw milk contains more beneficial nutrients, enzymes, and probiotics compared to pasteurized milk, which they believe can support immune and digestive health. However, the absence of pasteurization—a process that heats milk to kill harmful bacteria—also increases the risk of consumption of infectious agents.
Balancing Nutritional Benefits and Safety
While the nutritional claims about raw milk have some scientific backing, the new study underscores the critical trade-off between preserving potential health benefits and ensuring food safety. Consumers must consider these factors carefully, particularly given the emerging evidence linking raw milk consumption to possible flu virus transmission.
This study serves as a timely reminder of the potential risks associated with consuming unpasteurized dairy products. As food safety experts continue to explore ways to balance health benefits and disease prevention, public awareness about the importance of pasteurization remains vital in safeguarding public health.
FDA’s Warning on Raw Milk Safety
The Food and Drug Administration (FDA) along with the Centres for Disease Control and Prevention (CDC) has connected raw milk consumption to over 200 outbreaks of foodborne illnesses. These agencies caution that harmful germs like E. coli and Salmonella in raw milk pose serious health risks. Vulnerable groups, including children, the elderly, pregnant women, and individuals with weakened immune systems have faced dangers from such contamination.
Influenza Virus Survival in Raw Milk
In a recent study, researchers investigated how long a strain of human influenza virus known as H1N1 PR8, could survive in raw cow’s milk stored at standard refrigeration temperatures. The results revealed that the virus remained infectious for up to five days. This raises concerns about possible virus transmission through contaminated milk products.
Study co-lead author Mengyang Zhang, a postdoctoral scholar in civil and environmental engineering explained the implications: “The persistence of infectious influenza virus in raw milk for days raises concerns about potential transmission pathways. The virus could contaminate surfaces and other environmental materials within dairy facilities, posing risks to animals and humans.”
Viral RNA Persistence and Food Safety Implications
Beyond detecting live flu viruses, researchers also found influenza virus RNA—genetic material that doesn’t cause illness—persisting in raw milk for at least 57 days. While this RNA poses no direct health risk, its presence has important implications for food safety monitoring and environmental surveillance.
Pasteurization proved highly effective in neutralizing the influenza virus, eliminating infectious particles and reducing viral RNA by almost 90%. However, trace amounts of viral RNA still remained even after pasteurization by emphasizing the need for careful monitoring methods.
Study co-lead author Alessandro Zulli, also a postdoctoral scholar in civil and environmental engineering highlighted this issue: “The prolonged persistence of viral RNA in both raw and pasteurized milk has implications for food safety assessments and environmental surveillance, particularly because many of the techniques used in environmental surveillance detect RNA.”
Balancing Food Safety and Monitoring Practices
This research underscores the critical role of pasteurization in enhancing milk safety by effectively destroying infectious viruses. However, the detection of persistent viral RNA calls for more advanced surveillance techniques to ensure comprehensive food safety evaluations.
By raising awareness of these findings, researchers hope to inform public health policies and encourage improved pathogen monitoring systems to reduce potential risks associated with raw milk consumption.
Improving Disease Monitoring: Insights from Flu Virus Research
- Research Origins and Focus: The recent study on flu virus persistence in raw milk stems from an earlier project funded by the Stanford Woods Institute for the Environment's Environmental Venture Projects program. That initial research focused on human norovirus and viruses from the same subfamily responsible for the Covid-19 pandemic. Building on this foundation, researchers turned their attention to flu viruses and their potential transmission through food sources.
- Flu Virus Impact and Transmission Potential: In the U.S. alone, flu viruses infect over 40 million people and cause more than 50,000 deaths annually. Certain flu strains, such as swine flu, have demonstrated the ability to spread from animals to humans by leading to as many as 1.4 billion global infections during the 2009-2010 pandemic. Although bird flu has not yet caused significant outbreaks in humans, experts warn that the virus could mutate into a more dangerous form.
Bird Flu and Dairy Product Risks
Recent cases of bird flu detected in cattle have raised concerns about its possible transmission through milk and dairy products. Researchers emphasized the importance of enhancing disease monitoring systems as bird flu continues to spread among livestock. These findings underscore the need for more robust surveillance methods to prevent potential outbreaks.
Wastewater Monitoring for Early Detection
The study builds on earlier research by the same team, which pioneered the use of wastewater analysis to detect avian influenza. Their findings had showed that commercial and industrial dairy waste can serve as key indicators of virus activity in nearby cattle populations. This approach allows public health officials to identify potential outbreaks before they spread widely.
Study co-author Alexandria Boehm highlighted the innovative use of wastewater monitoring by stating, “We never thought that wastewater could be used to detect and respond to zoonotic pathogens circulating in the community. It has been amazing to watch our work on detection in wastewater scaled across the United States and the world.”
. . .
References: