Product review (5 stars): Miele Quirks, EASY FIX
I've had my Miele dishwasher for 6 years. It uses the least amount of water of nearly all machines. Therein lies the rub. It will leave some water in the drain basin after a cycle, but that water should be from the final rinse and should be clean. The problem is that all water contains some amount of minerals. After awhile, the build up of minerals within the machine starts to pick up and hold on to microscopic food particles. Then even larger amounts of food sludge. These particles decompose and can breed bacteria. This is true of all dishwashing machines.

To fix this and prevent it from reoccurring: Follow the instructions in your "Operating Instructions" manual to check and clean the drain pump and non-return valve. It's very easy and no tools are required. (On one occasion, I found a tooth pick stuck there.) Now here comes the FIX. Buy a product called "Dishwasher Magic" which you can buy online at Amazon or a number of other stores. Follow the instructions. SUPER EASY. You will be amazed at the like new appearance of your machine and the odor will be gone. I plan on using it again in about six months. In between, try using the same company's product called "Glisten" dishwasher crystals. I'm going to use it every 2 months or so.

This worked for me. I hope you have similar results. By the way if you have an iron problem with your water this will wipe away those stains as well. It's a low cost fix to get your expensive dishwasher humming along like new again. Best of luck!!!