Yap, there is this belief that more surface areas attract lots more bacteria, but dog's immune system are much stronger than humans and their immunity system is build up in this way as well. There are many known human germs that is around our living areas but is not affected by dogs. Nevertheless, I keep myself from worrying too much by putting ACV, garlic, grapefruit seed or oil of oregano which besides killing off germs and bacteria, they have a whole list of benefits to dogs.
My sammies are ok with the mess, even though they are all white. My malteses are the ones that puts me off leisure chews. They will be chewing into their mustache and the last time I give them bone, my eldest girl actually throw a tantrum when she couldn't get rid of the hair together with the chicken drumstick. . Initially I thought she was angry with other dogs since she dun bark alot except at the doors but after a few growls I finally realised she was angry with the drumstick! End up I have to hold on to it and let her chew ;). I also thought of tying those loose hair up but that will completely defeat the purposes of letting those white long coat flowing whenever they run around the house which my families enjoy watching.
I do agree that mincing the meat discourages chewing but I make up with lots of chew toys as well as dried tendons for leisure chews to save my furniture. ;) As for the calcium, I used eggshell powder and calculate the ratio nicely so that they still get enough of it.