Since it is your manager who is doing these things, and since he has not been receptive when you've mentioned this stuff in the past, is there any point in bringing it up again? It just doesn't sound like it will change his behavior.

You are still in the right -- it is gross for people to be dropping ham on the floor and washing it, nibbling while they are preparing food, and it's just wrong to be stealing cookies. The idea of wearing gloves is new to me. People in restaurants around here are required to wash/sanitize their hands, but not to wear gloves.

But even though you are right, do you think bringing this up would make a difference?

If you do have that conversation, I hope it goes well!