There should be a mesh filter at the bottom of the tub to prevent food bits from clogging the drain pump (assuming the machine doesn't drain to a garbage disposal which some machines do). Give that a rinse under the sink.
They make dishwasher cleaning agents specifically to clean out the machine. You could try those or something with the same active ingredient.
You may need to do a couple vinegar rinses and follow-up with an empty cycle or two to push all the "contaminated" water out.