Study Finds Infectious Flu Virus Can Persist in Refrigerated Raw Milk for Five Days
A recent study conducted by researchers at Stanford University has revealed that refrigerated raw milk can harbor the influenza virus, remaining infectious for up to five days. This research, published in the journal Environmental Science & Technology Letters, raises significant concerns about the potential health risks associated with the consumption of raw milk, especially amid rising incidents of avian influenza in dairy cattle.
The findings of the study highlight the potential dangers linked to consuming raw milk, which is often regarded as a natural alternative to pasteurized dairy products. Unlike pasteurized milk, which is treated to eliminate harmful pathogens, raw milk is consumed in its natural state, leading to claims by its proponents that it retains beneficial nutrients, enzymes, and probiotics. However, these benefits may come with a hidden risk of serious health issues.
According to the research, which involved examining the behavior of a specific strain of influenza virus, H1N1 PR8, the virus was able to survive and retain its infectious properties in raw cow's milk stored at standard refrigeration temperatures for a duration of five days. This persistent infectivity raises alarms regarding the pathways through which avian influenza could potentially be transmitted to humans through dairy products.
The study's senior author emphasized the pressing need for vigilance regarding food safety, particularly when it comes to raw milk consumption. The U.S. Food and Drug Administration (FDA) has previously linked raw milk to over 200 reported outbreaks of foodborne illnesses. Vulnerable populations, including children, the elderly, pregnant women, and individuals with compromised immune systems, face heightened risks when consuming raw milk due to the presence of pathogens such as E. coli and Salmonella.
In addition to the infectious capacity of the flu virus, the researchers noted that viral RNA, which contains genetic information but is not infectious, remained detectable in the milk for at least 57 days after initial contamination. While pasteurization effectively eradicated infectious influenza from the milk and reduced the amount of viral RNA by almost 90%, it did not completely eliminate the RNA, which has implications for food safety monitoring and environmental health assessments.
The implications of this research are particularly pertinent given the ongoing challenges posed by flu viruses, which annually infect millions in the U.S. alone and account for tens of thousands of deaths. The potential for zoonotic transmission--where diseases jump from animals to humans--underscores the necessity for enhanced monitoring systems, particularly in light of the recent detection of avian influenza in cattle.
As public health officials continue to explore innovative methods for detecting viral threats, the study contributes valuable insights into the importance of examining dairy facilities and practices. The researchers have previously pioneered the use of wastewater analysis for monitoring zoonotic pathogens, providing a proactive approach to safeguarding public health.
Overall, this study serves as a critical reminder of the importance of food safety practices and the need for individuals to be informed about the risks associated with consuming raw dairy products. Consumers are encouraged to consider the benefits of pasteurization, which significantly mitigates the potential health risks linked to raw milk.
