It was the fact that Rainbow Acres sold tons of raw milk, which has been illegal to sell across state lines since 1984. Within a state, rules about raw milk are left up to the state's discretion, but federal law prohibits interstate sales and for a good reason. Raw milk is not pasteurized, and as such, there's no good protection against things like E. coli, salmonella, and the pathogens responsible for causing tuberculosis and typhoid.