When I asked our State Health Inspector he admitted if someone brought their own clean containers I could sell milk and it 'probably' would be ok. He said it wouldn't be legal in Texas, but it was one of those 'iffy things' no one was going to come out and deal with it. However, I weighed the options of someone bringing a container not fully clean, or doing something awful like letting the milk sit out awhile and then blame me. I figured it just wasn't worth the hassle. I make soap out of my milk instead.
Containers: Ziploc and probably Hefty bags make 5 gallon size also. You may have to special order them, but they're nice to freeze milk in, and the 'soft melt' stage is pretty high. (135* or something in that range.)
