60-day aging process does not mitigate HPAI if cheese is made with milk containing the virus
March 20, 2025 | Montpelier, VT - In response to the ongoing concern about the Highly Pathogenic Avian Influenza (HPAI) virus in dairy cattle and dairy products, scientists at Cornell University’s College of Veterinary Medicine in collaboration with researchers at its College of Agriculture and Life Sciences conducted new research over the last several months testing the stability of HPAI during the aging process of cheese made with raw milk. Using a laboratory mini-cheese model and commercial raw milk cheese samples made with HPAI contaminated raw milk, preliminary results suggest that HPAI may survive the 60-day aging process in at least some varieties of raw milk cheese that is made with raw milk containing HPAI.
This news comes as Vermont continues to sample and test milk from Vermont dairy cattle farms as part of a United States Department of Agriculture (USDA) HPAI monthly testing program of milk destined to be pasteurized and processed into dairy products. To mitigate any HPAI risk, 90% of Vermont dairy farms that sell raw milk for raw milk cheese production have voluntarily joined this sampling program to test their milk weekly, despite not being part of the USDA sampling program. Vermont dairy officials anticipate that all raw milk cheese manufacturers will have their milk tested weekly soon.
Based on required testing of dairy animals moving nationally and in Vermont by USDA and Vermont officials since April 2024, we have no positive test results and no reason to believe HPAI is currently present in Vermont dairy animals or products. Additionally, there are no known links of any human HPAI cases across the country to the consumption of raw milk cheese. According to USDA and the FDA, pasteurized milk and pasteurized dairy products remain safe to consume as pasteurization kills harmful microbes and pathogens in milk, including HPAI.
Vermont is the only state in the country that has been proactively offering weekly testing to raw milk cheese makers, many of whom are also voluntarily participating in the milk sampling program. The Vermont Agency of Agriculture, Food & Markets is working in partnership with the raw milk cheese industry to screen for HPAI and help promote safety before raw milk cheese enters the marketplace. Vermont cheeses are wonderful because of the diligent work conducted daily by our exceptional cheese makers and the farmers that manage their herds to harvest high quality milk from healthy animals. Vermont is a national leader in raw milk cheeses and cheese quality, and the response to HPAI reflects our state dairy industry’s commitment to maintain food safety and high-quality dairy products.
For more information on HPAI please go to insert agency website link. For information on how to participate in the voluntary sampling program for raw milk sellers, please contact the Dairy Section at 802-828-2433.