Some dogs will try and inhale even large meaty bones, so you really need to work with these guys carefully. They should eventually work it out. Most dogs will learn eventually, but others, well, it may take a long time. So in summary, monitor meal times, and be sure to watch out for the greedy guts - and manage them carefully. Ok, there is bacteria everywhere.
Dogs have an amazing immunity system specifically designed to eat all manner of bacteria.
And a healthy BARF fed dog manages those bacteria without a problem. Interestingly, the only cases I have heard of dogs dying from e-coli or salmonella, were dogs fed commercial dog foods. The most important thing is to wash your hands thoroughly after feeding your dogs, and even after cutting up meat for your own meals. Our digestive systems are not quite as robust as our dogs, so we must protect ourselves. I use a spray bottle containg white vinegar which I spray about when I need some disinfecting.