Food safety

Recent reports that the H5N1 avian flu virus has been found in cow’s milk have raised questions about whether the U.S. milk supply is safe to drink. According to the federal Food and Drug Administration, the answer is yes, as long as the milk is pasteurized. Nonetheless, raw (unpasteurized) milk sales are up, despite health experts’ warning that raw milk could contain high levels of the virus, along with many other pathogens. As an extension food scientist in a state where raw milk sales are legal, I provide technical support to help processors produce high-quality, safe dairy foods. I also like to help people understand the confusing world of pasteurization methods on their milk labels, and why experts strongly discourage consuming raw milk and products made from it. What can make milk unsafe Dairy products, like many foods, have inherent risks that can cause a variety of illnesses and even death. Our milk comes from animals that graze outdoors and live in bar...

The discovery of fragments of avian flu virus in milk sold in U.S. stores, including in about 20% of samples in initial testing across the country, suggests that the H5N1 virus may be more widespread in dairy cattle than previously realized. The Food and Drug Administration, which announced the early results from its nationally representative sampling on April 25, 2024, was quick to stress that it believes the commercial milk supply is safe. The FDA said initial tests did not detect any live, infectious virus. However, highly pathogenic avian influenza virus can make cows sick, and the flu virus’s presence in herds in several states and new federal restrictions on the movement of dairy cows between states are putting economic pressure on farmers. Five experts in infectious diseases in cattle from the University of California, Davis – Noelia Silva del Rio, Terry Lehenbauer, Richard Pereira, Robert Moeller and Todd Cornish – explain what the test results mean, ho...

PFAS chemicals seemed like a good idea at first. As Teflon, they made pots easier to clean starting in the 1940s. They made jackets waterproof and carpets stain-resistant. Food wrappers, firefighting foam, even makeup seemed better with perfluoroalkyl and polyfluoroalkyl substances. Then tests started detecting PFAS in people’s blood. Today, PFAS are pervasive in soil, dust and drinking water around the world. Studies suggest they’re in 98% of Americans’ bodies, where they’ve been associated with health problems including thyroid disease, liver damage and kidney and testicular cancer. There are now over 9,000 types of PFAS. They’re often referred to as “forever chemicals” because the same properties that make them so useful also ensure they don’t break down in nature. Facing lawsuits over PFAS contamination, the industrial giant 3M, which has made PFAS for many uses for decades, announced a US$10.3 billion settlement with public w...

Mercury pollution is a global threat to human health, especially to unborn babies and young children. Exposure to methylmercury, a type that forms when mercury washes into lakes and streams, can harm children’s brain development and cause symptoms including speech impairment and muscle weakness in adults who consume seafood as their main food source. Methylmercury also threatens health and reproduction in fish and other wildlife. Humans, animals and birds are exposed to methylmercury when they eat fish and shellfish. Scientists have been working for decades to understand how and when fish accumulate mercury. This information is key for assessing mercury risks across different water bodies and landscapes, and for evaluating policy changes designed to reduce mercury emissions. For decades, scientists have used fish ear stones, known as otoliths, to gain insights into fish growth, migration, diet and the timing of their exposure to certain pollutants. These tiny structures of...

An outbreak of highly pathogenic avian influenza has spread through chicken and turkey flocks in 46 states since it was first detected in Indiana on Feb. 8, 2022. The outbreak is also taking a heavy toll in Canada and Europe. Better known as bird flu, avian influenza is a family of highly contagious viruses that are not typically harmful to most wild birds that transmit it, but are deadly to domesticated birds. The virus spreads quickly through poultry flocks and almost always causes severe disease or death, so when it is detected, officials quarantine the site and cull all the birds in the infected flock. As of early November, this outbreak had led to the culling of over 50 million birds from Maine to Oregon, driving up prices for eggs and poultry – including holiday turkeys. This matches the toll from a 2014-2015 bird flu outbreak that previously was considered the most significant animal disease event in U.S. history. Yuko Sato, an associate professor of veterinary me...