Do you still have your tonsils?
the ear, nose, throat doctor said my tonsils were fine.
When I still had my tonsils, every so often I would get food and stuff stuck in pockets they had. This stuff would dislodge and I would spit it up. It was white and had the consistency of cheese. It was awful smelling too.
i got the same thing... let me know if you figure it out. i've had it for a year and it's getting damn annoying. exactly as you describe it. my temporary solution is to reach back and poke out all the whitish things hidden back there... only lasts a day. i've gotten good at it though :)
As a teenager I used to bring up what looked like very small firm blocks of cream cheese and our children also have the same problem. We all have large tonsils and they have a honeycomb appearance. In the small cavities, particles of food become lodged and trapped. Possibly bacteria causes them to become foul and whitish in appearance. You can be just sitting and feel one appear at the back of your mouth without warning. At the age of 15 I started having chronic tonsilitis and eventually they were removed. I have not had this experience since losing my tonsils.