There is a bit of a smell from our dishwasher and searching through Internet forums I found what is probably the solution. Making sure that the drain line is high up and looped to create a proper air gap, and running a container of TANG powered drink mix through the machine once or twice a year.
The repair is simple, use a rubber-coated hose clamp or PVC conduit strap to get the loop of the drain line inside the sink base as high as possible above the disposal connection, preferably right up under the countertop. Sometimes I have add to the length of the drain line to accomplish this. Once done, I run a short cycle on the dishwasher to flush out the bad water, then let it fill up again, then pour a jar of powdered Tang breakfast drink into the dishwasher and let it run the full cycle. The dishwasher comes out clean and the smell is gone. I then advise the homeowners to run the Tang through it once or twice a year to keep the unit clean.The TANG I can do. It's the loop that's probably gonna be the problem.