You can safely drink raw milk, but it requires a level of hygiene that's challenging to impossible in a commercial dairy operation. The biggest issue with raw milk (...most of the time...) is listeria, and carefully cleaning the udder and teats prior to milking the cow eliminates almost all of that problem. But, again, this is very difficult to do on a commercial dairy farm, because you need to move through so many cows very, very quickly. If you have just couple cows, then it's easier to handle.