The US Food and Drug Administration (FDA) has announced the results of a study finding no detectable viable H5N1 bird flu virus in 167 dairy product samples. The study, which included milk, ice cream, and cheese, follows a previous one in which inactive virus particles were found in some dairy samples. The FDA emphasizes that pasteurized dairy products are safe to consume and notes that the samples used in the study were from cows not infected with the bird flu. The study comes amid concerns over the spread of the virus, with 13 human cases and 189 infected dairy herds across 13 states.