Puppy With Smelly Breath?

Anyone have any ideas as to what I can do for a puppy with stinky breath? I have a five month old Cocker and his breath stinks like anal glands. I brush his teeth at least every other day and am trying to do this more frequently. He does not have access to the litterbox and because I work from home and he's my shadow, I can safely say he's not pooping anywhere/eating stool. I live in an apartment, so he's not outside unless he's leashed, and because he'll grab everything, I'm super watchful as to what's on the ground so he doesn't eat something harmful or just plain gross.

He was just at the vet less than a week ago for a neuter and hernia repair, and had a full mouth check and cleaning while he was under due to a broken puppy tooth that needed to be pulled. There's no infection, abscess, something trapped in his teeth, and they did a full exam and bloodwork before putting him under. There's no apparent reason for the nasty breath, but it's raunchy.

It's been a long time since I had a puppy, so is this kind of normal for teething puppies? He has tips of some adult teeth starting to break through, so maybe he has ick-breath because of that? Are there any home remedies I can try to make his puppy smoochies a little less ripe?

Thanks in advance for any ideas!