if it was all of us dog lovers would be dead. a dog's saliva can contain a few pathogenic organisms but believe it or not there are more dangerous bacteria in a human's mouth (and we don't like the same parts that dogs do). infants raised with loving animals like dogs will grow up healthy and not have any more diseases than those raised without face-licking dogs. as a matter of fact the face-licked babies may even be immunologically stronger. with that said i don't think you should encourage dog saliva exposure but nor should you be appalled dogs express their love to humans by licking and this dog loves the baby.
is a dog's saliva dangerous to infants?