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 Roe 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’re in full attack mode,” he said, describing the search as 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.
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 at the U.S. Department of Agriculture, said in an email.
CDFA officials could not be reached for comment Wednesday, but infectious disease experts told the Times that the agency is probably reviewing its testing procedures and the actual source of the milk sampled. I think so.
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 division 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 borderline positive for some tests and negative for others,” he said after reviewing his test records. I did.
Webby, Corsland and other experts say the test used only looks 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.
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 raw, unpasteurized 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 has recalled all products associated with the positive sample. McAfee estimates the recall involves 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 found the virus in 20% of samples collected from retail shelves. However, when further testing was done, namely isolation of the virus, they were able to show that it was an inactivated virus denatured by heat.
So why is it that even though raw milk samples have high virus test results, dairy cows do 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 subsequent lack of positive tests suggested “a product integrity issue rather than an outbreak.”
“What if somewhere in the bottling process, raw milk is adulterated with pasteurized shelf milk to meet insufficient supply demands? In such a scenario, there is no testing issue; rather, it is usually 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) of the bulk milk by the state agriculture department came back negative. He also said a test he took on Monday did not detect the virus.
He also said each cow on the farm is monitored using high-tech equipment made by 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. Ta.
He said based on these data there is no sign that the virus is moving through the herd.
He also said all operations, including trucks, bulk tanks and bottling plants, are closed to outside farms and milk. These are used only by Raw Farm.
He said he worries state officials are determined to “find something.”
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