Less than a week after California health officials confirmed the avian influenza virus had been detected in store-bought raw milk, state agriculture officials said Wednesday that “unprecedented” by Mark McAfee Low Farm Dairy Farm and began collecting samples from the farm’s two herds, creamy, dairy, and raw milk. According to the owner, a large number of milk tanks and trucks.
The visit follows a recall of Raw Farm products and comes amid a spate of H5N1 avian influenza outbreaks at state dairy farms. McAfee said Law Farm manages 1,800 cows across two herds, one in Fresno and one outside Hanford. The company also owns a Fowler-based creamery.
“I think they are in full attack mode,” he said, explaining that the search was thorough. In addition to milk, Raw Farm also produces cheese and kefir.
On Wednesday, as California Department of Food and Agriculture officials collected samples and conducted tests at the dairy farm, some health experts expressed doubts and concerns about the recent positive test results.
read more: Despite warnings from bird flu experts, it’s business as usual in California’s dairy country
Last week, Santa Clara County public health officials detected the avian influenza virus in a sample of McAfee’s store-bought raw milk. Two days later, the California Department of Public Health confirmed the finding.
However, when state agriculture officials tested cows at McAfee’s dairy farm on Monday, no virus was detected.
The fact that no animals are known to be infected with the virus has puzzled and concerned public health experts. Generally, once a virus appears on a farm, it doesn’t just disappear; it spreads.
“The fact that all of the additional tests are negative is really concerning,” John Corsland, a former veterinary epidemiologist with the U.S. Department of Agriculture, said in an email.
CDFA officials were not available for comment Wednesday, but infectious disease experts told the Times that the agency is likely reviewing testing procedures and the actual source of the milk sampled. .
Initial samples of store-bought raw milk were found to contain high levels of the virus, with a polymerase chain reaction cycle threshold (Ct) of approximately 25, according to laboratory records.
“According to IMO, a herd should not test negative immediately after showing a value of 25 if it is indeed milk from the same herd,” Courseland wrote in an email.
Richard Webby, director of the World Health Organization’s Collaborating Center for Animal and Avian Influenza Ecology and a researcher in the Department of Infectious Diseases at St. Jude Children’s Research Hospital in Memphis, Tennessee, agreed.
“Okay, this is not a weak positive…and it’s definitely not on the borderline where some tests are positive and others are negative,” he said after reviewing his test records. Ta.
Webby, Corsland and other experts say the tests used only look for the H5 portion of the H5N1 virus and cannot determine whether the virus is inactive or live. A second test (called a virus isolation test) must be performed to confirm that the sample is H5N1 and is active.
read more: Warning issued for contaminated raw milk sold in Los Angeles County stores
State and federal health officials say the H5N1 avian influenza virus poses a low risk to the public. However, they urge people not to drink unpasteurized raw milk. There have been no reports of consumer outbreaks associated with avian influenza in contaminated raw milk.
The milk was bottled on November 9th. Law Farm LLC has recalled all products associated with the positive sample. McAfee estimates the recall includes approximately 2,000 half-gallon and quarter-gallon “CreamTop” whole dairy products.
Since the outbreak began, 461 herds in California have been infected, including those in Fresno and Kings County, where McAfee’s herd is located.
Early in the H5N1 dairy outbreak, federal health officials tested samples of pasteurized milk and Viruses were found in 20% of samples Collected from retail store shelves. However, when further tests were carried out, i.e. isolation of the virus, they were able to show that it was an inactivated virus denatured by heat.
So why did raw milk samples test highly for the virus, but dairy cows did not test positive?
Mr. Courseland acknowledged that testing and sampling can sometimes be compromised, but he did not question the testing in this case. He said the Ct value and lack of subsequent positive tests suggested “a product integrity issue rather than an outbreak.”
“What if, somewhere in the bottling process, raw milk is adulterated with pasteurized and preserved milk to meet insufficient supply demand? In such a scenario, there is no testing issue. “It’s an undetectable product integrity issue,” he said.
This is why virus isolation testing is important, Korslund said. It will help determine whether the virus in the sample taken is live.
A spokesperson for the state health department said testing of the samples had been completed. He did not say whether the virus had been isolated, but noted that positive results had been confirmed by state and now federal labs.
McAfee said he does not believe the virus is present in his herd. Regular tests (twice a week) by the state Department of Agriculture on his large quantities of milk came back negative. He also said that a test he took on Monday did not detect the virus.
In addition, each cow on the farm is monitored using high-tech equipment from Austrian company smaXtec, which is placed in the cow’s udder and transmits real-time information about the animal’s body temperature, lactic acidity, and more. spoke.
He said based on that data there is no indication the virus is moving through the herd.
He also said all equipment, from trucks to bulk tanks to bottling plants, is closed to outside farms and milk. They are used only by Raw Farm, LLC.
He said he worries state officials are determined to “find something.”
This story was originally Los Angeles Times.
