>>10
It's mostly illegal because of outdated views on sanitation and whatnot that date back to the early 20
th century. That was during a time when refrigerated trucks weren't practical yet, farms weren't as clean because germs and contamination wasn't properly controlled due to lack of knowledge and technology at the time. Hence the push for pasteurization. Remember, this was a time when sawdust was being found in consumable meat.
Today, that is simply not the case and what's ironic is that the current factory farms produce a ton of water and air pollution, ruin water tables, and basically just turn the surrounding area into a wasteland. A traditional conventional farm equipped with reasonable modern technology produces only 1/3rd of the pollution what most of those factory farms produce. Of course if if this were broadcasted every night on the news and this was common knowledge, all those companies lobbying politicians in Washington would be in an uproar from competition from small farmers.
However, it's not all bad, as it's legal in 28 out of 50 states, so I guess things could be a lot worse. However, having a Federal ban on the interstate transport of consumable liquid is not the workings of a free society.