LOS ANGELES/CHICAGO, May 2 (Reuters) - U.S. sellers of raw milk appear undeterred by federal health warnings for consumers to avoid drinking unpasteurized milk in light of a bird flu outbreak that has affected dairy herds in nine states and sickened at least one dairy farm worker.

Thirty of the 50 U.S. states permit the sale of raw milk, which accounts for less than 1% percent of U.S. milk sales. A nationwide survey of pasteurized milk - heated to kill pathogens - found avian flu virus particles in about 20% of samples tested.

Many raw milk drinkers share a deep skepticism of public health officials, including the U.S. Food and Drug Administration (FDA), which also battled political polarization and misinformation during and after the COVID pandemic.