Latest news with #DiegoDiel
Yahoo
17-03-2025
- Health
- Yahoo
Bird flu virus may survive aging process in raw milk cheese
There's a new reason to steer clear of raw cheese: New research shows it can harbor the infectious bird flu virus for months. "There is a risk of infection," lead study author Dr. Diego Diel, an associate professor at Cornell University, told CNN. "It obviously depends on the dose, how much of that contaminated product is ingested." Though it's illegal to sell raw milk across state lines, since 1949 it's been legal to sell raw milk cheese provided it has been aged for at least 60 days. That period allows for development of natural acids and enzymes that have been thought to destroy pathogens. The new research -- funded by the U.S. Food and Drug Administration -- demonstrates that this aging alone may not inactivate the H5N1 bird flu virus. The same team had previously shown that the H5N1 virus stayed infectious for up to eight weeks in refrigerated raw milk. "The protein and fat content in the cheese and milk provide a good environment for the virus to survive at refrigeration temperature," Diel said. For the study, his team made mini cheeses that they laced with the H5N1 virus. The cheeses were produced at three pH levels, from the least acidic, 6.6, to the most acidic, 5.0. Researchers then injected samples of the cheeses into fertilized chicken eggs to see how long any virus able of causing infection remained. For the first seven days, levels of virus remained high, then fell in the two least acidic cheeses. Significantly, levels remained infectious for the full two-month aging period. "Our study demonstrates that HPA1 H5N1 virus exhibits remarkable stability throughout the cheese making process," the authors wrote, suggesting that making raw milk cheese more acidic may make it safer to eat. No live virus was detected in the most acidic cheese (pH 5.0). Other research has shown that pasteurization inactivates the virus. Seema Lakdawala, an associate professor of microbiology and immunology at Emory University who also studies H5N1 transmission, reviewed the findings. "We have also observed that milk can change the pH needed to inactivate the virus," Lakdawala told CNN, adding that "a much lower pH than is normal is needed to inactivate the virus." Despite the new findings, the head of the U.S. health system, has said food doesn't present a bird flu risk. "The disease is not passed through food so you cannot get it -- as far as we know, you cannot get it from an egg or milk or meat from an infected animal," Robert F. Kennedy Jr., secretary of the U.S. Department of Health and Human Services, told Fox News last week. While there are no confirmed cases of people being sickened from eating or drinking foods that contain viruses, including raw milk cheese, dairy workers have been infected when raw milk splashed their faces or eyes. Diel told CNN it's not entirely clear whether people can be infected by consuming contaminated food and that his study was not designed to answer that question. The findings are posted on the preprint server bioRxiv. Until it is published in a peer-reviewed journal, findings should be considered preliminary. The FDA also posted the findings on Friday along with early results from an ongoing sampling study of raw cheese announced in December. Of 110 cheese samples taken from stores across the country, 96 tested negative for live virus as well as inactive viral particles. The agency said that indicates they were probably not made with contaminated milk. Results of 14 samples are pending. "The FDA is confident that pasteurization is effective at inactivating H5N1, and that the commercial, pasteurized milk supply is safe," the agency said in a statement. Checking the product label may help -- but it's not foolproof, however. "While there is no express Federal requirement for the labeling of cheeses to disclose on the ingredient list whether the milk used in manufacture was raw or pasteurized, many cheeses do disclose on the ingredient list (or elsewhere on the product label) if the milk used is pasteurized or raw," the statement said. "The FDA is not aware of any H5N1 illnesses to date from the consumption of aged raw milk cheese products." More information There's more about H5N1 bird flu at the Cleveland Clinic. Copyright © 2025 HealthDay. All rights reserved.
CNN
15-03-2025
- Health
- CNN
H5N1 bird flu virus is infectious in raw milk cheese for months, posing risk to public health, study shows
Raw cheese made with milk from dairy cattle infected with bird flu can harbor infectious virus for months and may be a risk to public health, according to a new study from researchers at Cornell University that was funded by the US Food and Drug Administration. Raw milk cheeses are those made with milk that hasn't been heat-treated, or pasteurized, to kill germs. Although federal law prohibits the sale of raw milk across state lines, sales of raw milk cheese are legal nationwide as long as it's aged at least 60 days before landing on store shelves. This requirement, which has been in place since 1949, is thought to cut the risk of contamination, since it allows development of natural acids and enzymes, which were believed to kill off pathogens. The new study shows that this aging process may not inactivate the H5N1 virus, however, and it underscores the risk of consuming raw or undercooked foods during the bird flu outbreak, which continues to infect dairy cattle, poultry and a growing number of other animal species. The same group of researchers previously found that H5N1 virus remained infectious in refrigerated raw milk for up to eight weeks. Dr. Diego Diel, who led the study, says he thinks the virus may be so stable in milk and cheese because it's protected by the complex matrix of molecules around it. 'The protein and fat content in the cheese and milk provide a good environment for the virus to survive at refrigeration temperature,' said Diel, an associate professor of virology at Cornell. Robert F. Kennedy Jr., secretary of the US Department of Health and Human Services, has said food doesn't pose a bird flu risk. 'The disease is not passed through food, so you cannot get it – as far as we know, you cannot get it from an egg or milk or meat from an infected animal,' Kennedy told Fox News in an interview that aired Tuesday. But that's only partly true. Cats and other animals have been infected by raw cow's milk and raw pet food, and there have been at least three confirmed human infections in which investigators were unable to determine the source of the person's exposure to the H5N1 virus. There have been no confirmed reports of people getting sick from eating or drinking bird-flu contaminated foods, including raw milk cheese, but dairy workers have been infected by getting splashed with raw milk in their faces or eyes. It's still not entirely clear whether humans can be infected by eating or drinking contaminated food, Diel said, noting that his study wasn't really designed to answer that question. 'I do think it is possible. There is a risk of infection,' he said. 'It obviously depends on the dose, how much of that contaminated product is ingested.' It may also depend on the strain of virus in the milk or cheese. Diel and his team tested the stability of the B3.13 virus, which originally infected cattle in the US in March 2024. B3.13 has caused only mild disease in people. However, a new strain, D1.1, which has been associated with some severe human cases, has also crossed into cattle, further increasing the risk. For the study, the researchers made mini cheeses with milk they spiked with H5N1 virus. They made these cheeses at three pH levels: 6.6, 5.8 and the most acidic formula, 5.0. The researchers then tested the cheeses over time to see whether any virus capable of infecting cells remained. They injected samples into fertilized chicken eggs, considered the gold standard test. Levels of the virus remained high for the first seven days after the cheese was made and then dropped a bit in the cheeses produced at pH levels 6.6 and 5.8. But importantly, the virus remained infectious for the full two-month aging period, showing that it was remarkably stable in the cheese over a long period. Those results were confirmed by some real-world examples. The researchers tested samples of raw milk cheese from a farm that had inadvertently produced them with milk from cows infected with bird flu. These findings also showed that levels of virus stayed high and remained infectious over the full two months of aging. 'Our study demonstrates that HPAI H5N1 virus exhibits remarkable stability throughout the cheese making process,' the authors wrote in their preprint study, posted ahead of peer review Friday. However, the study suggested that making raw milk cheese more acidic may kill the virus and make the cheese safer to eat. No live virus was detected in the cheese produced at the lowest pH, 5.0. Prior studies have also shown that common pasteurization methods inactivate the virus. Experts said the new study was consistent with tests of the stability of the virus in milk. 'We have also observed that milk can change the pH needed to inactivate the virus,' said Dr. Seema Lakdawala, an associate professor of microbiology and immunology at Emory University, who has been studying the transmission of H5N1. 'We and others have repeatedly observed that milk will prevent the degradation of the virus on surfaces, and it increases the pH stability, such that a much lower pH than normal is needed to inactivate the virus,' said Lakdawala, who was not involved in the new study. The FDA posted the findings of the study Friday along with preliminary results from its own ongoing sampling study of raw cheese. The FDA sampling study, which was announced in December, has tested 110 cheese samples taken from store shelves across the country. So far, 96 of those samples were negative by polymerase chain reaction testing, or PCR, which detects live virus as well as inactive viral particles, indicating that those cheeses probably weren't made with contaminated milk. The results from the remaining 14 samples are pending, the agency said. 'The FDA is continuing to work with Federal and state partners to address the ongoing outbreak of HPAI A (H5N1) in dairy cattle. The FDA has sampled a total of 464 pasteurized dairy products, including milk cheese butter and ice cream, all were negative for viable H5N1. In addition, multiple research studies have confirmed that pasteurization inactivates the virus,' the statement said. Still, experts say the study is a good reminder of the importance of surveillance – and of not consuming raw milk products. 'This is another reason we should push to ensure there is no bird flu in milk products and only consume pasteurized dairy products,' Lakdawala said.
CNN
14-03-2025
- Health
- CNN
H5N1 bird flu virus is stable and infectious in raw milk cheese for months, study shows
Raw cheese made with milk from dairy cattle infected with bird flu can harbor infectious virus for months and may be a risk to public health, according to a new study from researchers at Cornell University that was funded by the US Food and Drug Administration. Raw milk cheeses are those made with milk that hasn't been heat-treated, or pasteurized, to kill germs. Although federal law prohibits the sale of raw milk across state lines, sales of raw milk cheese are legal nationwide as long as it's aged at least 60 days before landing on store shelves. This requirement, which has been in place since 1949, is thought to cut the risk of contamination, since it allows development of natural acids and enzymes, which were believed to kill off pathogens. The new study shows that this aging process may not inactivate the H5N1 virus, however, and it underscores the risk of consuming raw or undercooked foods during the bird flu outbreak, which continues to infect dairy cattle, poultry and a growing number of other animal species. The same group of researchers previously found that H5N1 virus remained infectious in refrigerated raw milk for up to eight weeks. Dr. Diego Diel, who led the study, says he thinks the virus may be so stable in milk and cheese because it's protected by the complex matrix of molecules around it. 'The protein and fat content in the cheese and milk provide a good environment for the virus to survive at refrigeration temperature,' said Diel, an associate professor of virology at Cornell. Robert F. Kennedy Jr., secretary of the US Department of Health and Human Services, has said food doesn't pose a bird flu risk. 'The disease is not passed through food, so you cannot get it – as far as we know, you cannot get it from an egg or milk or meat from an infected animal,' Kennedy told Fox News in an interview that aired Tuesday. But that's only partly true. Cats and other animals have been infected by raw cow's milk and raw pet food, and there have been at least three confirmed human infections in which investigators were unable to determine the source of the person's exposure to the H5N1 virus. There have been no confirmed reports of people getting sick from eating or drinking bird-flu contaminated foods, including raw milk cheese, but dairy workers have been infected by getting splashed with raw milk in their faces or eyes. It's still not entirely clear whether humans can be infected by eating or drinking contaminated food, Diel said, noting that his study wasn't really designed to answer that question. 'I do think it is possible. There is a risk of infection,' he said. 'It obviously depends on the dose, how much of that contaminated product is ingested.' It may also depend on the strain of virus in the milk or cheese. Diel and his team tested the stability of the B3.13 virus, which originally infected cattle in the US in March 2024. B3.13 has caused only mild disease in people. However, a new strain, D1.1, which has been associated with some severe human cases, has also crossed into cattle, further increasing the risk. For the study, the researchers made mini cheeses with milk they spiked with H5N1 virus. They made these cheeses at three pH levels: 6.6, 5.8 and the most acidic formula, 5.0. The researchers then tested the cheeses over time to see whether any virus capable of infecting cells remained. They injected samples into fertilized chicken eggs, considered the gold standard test. Levels of the virus remained high for the first seven days after the cheese was made and then dropped a bit in the cheeses produced at pH levels 6.6 and 5.8. But importantly, the virus remained infectious for the full two-month aging period, showing that it was remarkably stable in the cheese over a long period. Those results were confirmed by some real-world examples. The researchers tested samples of raw milk cheese from a farm that had inadvertently produced them with milk from cows infected with bird flu. These findings also showed that levels of virus stayed high and remained infectious over the full two months of aging. 'Our study demonstrates that HPAI H5N1 virus exhibits remarkable stability throughout the cheese making process,' the authors wrote in their preprint study, posted ahead of peer review Friday. However, the study suggested that making raw milk cheese more acidic may kill the virus and make the cheese safer to eat. No live virus was detected in the cheese produced at the lowest pH, 5.0. Prior studies have also shown that common pasteurization methods inactivate the virus. Experts said the new study was consistent with tests of the stability of the virus in milk. 'We have also observed that milk can change the pH needed to inactivate the virus,' said Dr. Seema Lakdawala, an associate professor of microbiology and immunology at Emory University, who has been studying the transmission of H5N1. 'We and others have repeatedly observed that milk will prevent the degradation of the virus on surfaces, and it increases the pH stability, such that a much lower pH than normal is needed to inactivate the virus,' said Lakdawala, who was not involved in the new study. The FDA posted the findings of the study Friday along with preliminary results from its own ongoing sampling study of raw cheese. The FDA sampling study, which was announced in December, has tested 110 cheese samples taken from store shelves across the country. So far, 96 of those samples were negative by polymerase chain reaction testing, or PCR, which detects live virus as well as inactive viral particles, indicating that those cheeses probably weren't made with contaminated milk. The results from the remaining 14 samples are pending, the agency said. 'The FDA is continuing to work with Federal and state partners to address the ongoing outbreak of HPAI A (H5N1) in dairy cattle. The FDA has sampled a total of 464 pasteurized dairy products, including milk cheese butter and ice cream, all were negative for viable H5N1. In addition, multiple research studies have confirmed that pasteurization inactivates the virus,' the statement said. Still, experts say the study is a good reminder of the importance of surveillance – and of not consuming raw milk products. 'This is another reason we should push to ensure there is no bird flu in milk products and only consume pasteurized dairy products,' Lakdawala said.
CBS News
21-02-2025
- Health
- CBS News
Michigan dairy workers' cats died from bird flu, but it's not clear how they got infected
Two cats that belonged to Michigan dairy workers died after being infected with bird flu. But it's still not clear how the animals got sick or whether they spread the virus to people in the household, a new study shows. Veterinary experts said the report, published Thursday by the U.S. Centers for Disease Control and Prevention, lacks detail that could confirm whether people can spread the virus to domestic cats — or vice versa. "I don't think there is any way of concluding that there was human-to-cat transmission based on the data that is presented," said Dr. Diego Diel of the Cornell University College of Veterinary Medicine. Cats in two separate households died in May after developing severe illnesses that were confirmed as the Type A H5N1 bird virus found in U.S. dairy herds, investigators reported. Both were indoor-only cats that had no exposure to infected cattle or birds and didn't consume raw milk. One cat that died belonged to a worker on a dairy farm in a county known to have bird flu-infected cattle. The worker reported symptoms of illness before the cat got sick. That cat fell ill, tested positive for H5N1 and had to be euthanized. A second cat in that household also got sick, but it recovered. A third cat in the household didn't get sick and tested negative. Meanwhile, an adolescent in the household got sick but tested negative for flu. The other cat that died lived in a different household. That pet belonged to a dairy worker who transported raw milk and reported frequent splashes of milk on the face, eyes and clothing. That worker reported eye irritation, a possible symptom of bird flu, two days before the cat got sick. The cat was known to roll in the worker's dirty clothing and died within a day of developing signs of infection, the study authors wrote. Another cat in that household tested negative for the virus. In both instances, the dairy workers declined to be tested for H5N1, the study said. That means it's impossible to know whether they directly transmitted the virus to their cats, said Dr. Keith Poulsen, director of the Wisconsin Veterinary Diagnostic Laboratory. It's more likely that the cats were infected by virus on the workers' clothing, boots or hands, he said. "We know that people at this point are not shedding large amounts of virus," he said. "I don't think it's because this person coughed on their cat." The study concluded that reports of bird flu infections in indoor cats are rare, but "such cats might pose a risk for human infection." In the months since the cats died, there have been several reports of domestic cats becoming infected and dying after consuming unpasteurized milk or pet food contaminated with bird flu. The new report underscores the need for more comprehensive testing for H5N1 in all arenas, Poulsen said.
The Independent
20-02-2025
- Health
- The Independent
Dairy workers' cats died from bird flu, but it's not clear how they got infected
Two cats that belonged to Michigan dairy workers died after being infected with bird flu. But it's still not clear how the animals got sick or whether they spread the virus to people in the household, a new study shows. Veterinary experts said the report, published Thursday by the U.S. Centers for Disease Control and Prevention, lacks detail that could confirm whether people can spread the virus to domestic cats — or vice versa. 'I don't think there is any way of concluding that there was human-to-cat transmission based on the data that is presented,' said Dr. Diego Diel of the Cornell University College of Veterinary Medicine. Cats in two separate households died in May after developing severe illnesses that were confirmed as the Type A H5N1 bird virus found in U.S. dairy herds, investigators reported. Both were indoor-only cats that had no exposure to infected cattle or birds and didn't consume raw milk. One cat that died belonged to a worker on a dairy farm in a county known to have bird flu-infected cattle. The worker reported symptoms of illness before the cat got sick. That cat fell ill, tested positive for H5N1 and had to be euthanized. A second cat in that household also got sick, but it recovered. A third cat in the household didn't get sick and tested negative. Meanwhile, an adolescent in the household got sick but tested negative for flu. The other cat that died lived in a different household. That pet belonged to a dairy worker who transported raw milk and reported frequent splashes of milk on the face, eyes and clothing. That worker reported eye irritation, a possible symptom of bird flu, two days before the cat got sick. The cat was known to roll in the worker's dirty clothing and died within a day of developing signs of infection, the study authors wrote. Another cat in that household tested negative for the virus. In both instances, the dairy workers declined to be tested for H5N1, the study said. That means it's impossible to know whether they directly transmitted the virus to their cats, said Dr. Keith Poulsen, director of the Wisconsin Veterinary Diagnostic Laboratory. It's more likely that the cats were infected by virus on the workers' clothing, boots or hands, he said. 'We know that people at this point are not shedding large amounts of virus,' he said. 'I don't think it's because this person coughed on their cat.' The study concluded that reports of bird flu infections in indoor cats are rare, but 'such cats might pose a risk for human infection.' In the months since the cats died, there have been several reports of domestic cats becoming infected and dying after consuming unpasteurized milk or pet food contaminated with bird flu. The new report underscores the need for more comprehensive testing for H5N1 in all arenas, Poulsen said. ___ The Associated Press Health and Science Department receives support from the Howard Hughes Medical Institute's Science and Educational Media Group and the Robert Wood Johnson Foundation. The AP is solely responsible for all content.
