I have a Bull Mastiff and she gets these too. I asked the vet once and she said it's caused by her mouth being wet and food staying on her mouth because of the way her jaws are aligned. I don't know if that is what your dog has but I can control it to a certain extent by drying and cleaning her mouth after she eats or drinks and plain yogurt helps with many things that happen to dogs like ear infections and upset stomachs. Hope this helps.
