United States: The H5N1 influenza, sometimes known as bird flu, can infect cows. According to recent lab tests, the virus can spread when milk from affected cows is left raw or untreated, and it may even spread when flash pasteurized.
Urgent Response from Research Network
The University of Wisconsin School of Veterinary Medicine researchers are a part of the Centers of Excellence for Influenza Research and Response, or CEIRR, a federally sponsored program. In an effort to address urgent concerns regarding the H5N1 outbreak in dairy cattle, this network has been undertaking quick research.
The researchers report the findings of tests utilizing milk from four contaminated cows—two from Kansas and two from New Mexico—in a research letter published online in the New England Journal of Medicine on Friday.
Findings and Safety Measures
Since the H5N1 virus is regarded as a select agent, it was handled under tight safety procedures in a high-security Biosafety Level 3 lab at the University of Wisconsin.
They began by confirming that the raw milk was tainted with the H5N1 virus. Subsequently, they refrigerated a portion of the raw milk to observe if the virus would gradually decrease in the milk. Viral levels in raw milk decreased somewhat, but not significantly, over a 5-week period.
Dr. Seema Lakdawala, an associate professor of immunology and microbiology at Emory University and a member of the CEIRR network, expressed alarm about the fact that the material was not deteriorating over time despite not being included in the study.
The experimenters also tested a variety of pasteurization ways to determine which bones could be most effective at rendering the contagion inactive.
Small samples of milk were hotted to the times and temperatures used in two different types of pasteurization high- temperature short- time, or flash pasteurization, which is the most extensively habituated system in the US moment, and low- temperature, long- time, or handbasket pasteurization.
The contagion was lowered to undetectable situations by hotting the milk to 63 degrees Celsius, or 145 degrees Fahrenheit, for intervals of 5 to 30 twinkles. This process is known as handbasket pasteurization.
Small samples of milk that were heated to the times and temperatures and it is used in the two different types of pasteurization: high- temp and short time, or flash pasteurization, which is the most widely method used in the US today, and low-temperature, long-time, or vat pasteurization.
The virus was lowered to the undetectable levels by heating the milk to 63 degrees Celcius
The virus was significantly decreased but not entirely inactivated by heating the milk to 72 degrees Celsius, or 181 degrees Fahrenheit, for 15 or 20 seconds, which was similar to flash pasteurization.
Potential Implications for Food Industry
The US Food and Drug Administration refers to this test as the “gold-standard” for figuring out whether viruses can still infect milk because it shows that milk samples heated for 15 or 20 seconds can still infect incubated chicken eggs.
“But, we emphasize that the conditions used in our laboratory study are not identical to the large-scale industrial treatment of raw milk,” senior study author Dr. Yoshihiro Kawaoka, a virologist who specializes in the study of flu and Ebola, said in an email.
According to Lakdawala, there’s no need to panic over the study’s results.
According to Lakdawala, preheating is a necessary step in commercial flash pasteurization, which was skipped in this instance. In order to prevent the cream from separating, homogenization—a procedure that emulsifies the fat globules in milk—is also included. Although the results of this study indicate that the entire process of commercial flash pasteurization should be carried out “with all the steps in place,” she continues, those two processes would likely make it more difficult for the virus to survive.