3 Answers

hydrogen peroxide

Look at the bottom of the door.  I found the most awful slimy mold there.  Don't touch it, clean it away with paper towel.  Look all around inside and on the seals of the door for food and slime.

Suggest you put a quart of white vineger in the dishwasher and run it throught a cycle. 

Besides getting rid of the odor it got rid of the "stuff" that was making the glasses look foggy.

     Inside mine, on the bottom near the back, there's a grate where food particles accumulate.  If yours is like this, remove that food.  If not, it sounds like there's somewhere that old food is being retained.  Unless you can take it apart yourself, you may have to get a repairman.