This is a very interesting thread! I admit I am definitely and unapologetically overprotective of Chloe and have swiped more yukky stuff than I care to discuss out of her mouth. She is, like most of the others have mentioned, CONSTANTLY sniffing and tries to taste EVERYTHING in her path! I, too, have worried about the safety of what she gets into - germ and toxin-wise. (During recent wet weather our yard was full of strange mushrooms and I spent a lot of time clearing them from her area as a precaution.) But on our walks I am very aware of what is in front of us as Chloe will, without a doubt, try to eat whatever she sees! I am reminded frequently of when our children were babes and toddlers and I was "baby-proofing" continuously!!
BTW, the saliva theory is REALLY interesting!! I like it - it makes ME feel better, anyway!!
Margo