With concern over the bird flu continuing to mount across the country, one Inland Empire man says that his beloved pets fell victim to the virus after drinking contaminated raw milk.

The Food and Drug Administration (FDA) has begun collecting and testing samples of aged, raw cow’s milk cheese for the presence of Highly Pathogenic Avian Influenza (H5N1), better known as bird flu, Food Safety News reported.

Raw, unpasteurized milk is a known vector of bird flu when derived from infected cow herds. It can also contain pathogens such as E. coli, salmonella, and both Streptococcus and Staphylococcus bacteria.