Dishwashers can turn smelly, especially if it is an older model. Here is how to get a fresh smelling dishwasher once again so you aren’t thinking “Ewwww!” everytime you open it.
First, check the bottom drainage catch to make sure there is no food in there caught that is making it smell. Sometimes if there is a large piece of food caught there, it can cause the bad smell.
To clean it, pour 1/2 gallon to a gallon (depending on how strong the smell is!) of vinegar into the bottom of the dishwasher. Allow it to sit and soak for an hour, then run a normal wash cycle (use the full cycle not the quick clean function).
You may need to repeat this more than once if it is extremely strong smelling, then repeat every month or so to keep it smelling fresh. If this does not resolve it, you might consider phoning a plumber incase the issue is something to do with the way it was plumbed originally.