If there's any one thing I'm O/C about, it's my food being contaminated. I'll thoroughly inspect all of my plates, bowls, glasses, spoons, and forks, and if there's so much as a speck on them I'll either wash them out vigorously or use a different one. If, say, I'm eating a burger and there's a black speck on my bun, I'll pick that bastard off. I pick flakes of cereal that are darker than they should be out of my bowl. And drinking/eating after or sharing utensils with other people is completely out of the question.
Now, do you really think someone like me is going to eat something that's been dropped onto a dirty floor? D: I'd sooner have no cookie than a cookie covered in floornasty.