Recently , I have been experiencing a sudden fould taste in my mouth after swallowing food. It doesn't happen all the time though. It started happening a little over a year ago and didn't happen again for a long time. In the last few months, I have noticed that is happening more often ( about once a week ). The taste is foul, almost like something rotten. I visit a dentist every 6 months for cleaning and checkup and had a checkup with no problems about 1 month ago. It does not seem like it is coming from my mouth, rather coming up from the esophagus region. What could this be? I have searched the web and cannot really find anything like this. Also, I had a papilloma removed from the middle of my hard palate about 7 months ago. It was there for a couple years and was about 1-2 mm in width.