What causes phlegm in throat and food stuck on it?

Reflux: Phlegm in the throat associated with food may be from acid reflux. When acid reflux makes it to the level of your throat it is called lpr. In some instances chronic inflammation in the tonsils may cause similar symptoms. I rare cases, a pouch like space called a diverticulum(zenker's) can occur in the upper esophagus which can produce mucous and debris.