You do the same thing that you would normally do just without a dishwasher. Soap, water, water/vinegar mix, baking soda, and bleach are all the chemicals you need to clean with.
I'd add something snarky in here about not being sure if serious but I guess I can see how someone may have grown up with the impression that a dishwasher is some fantastical device that autoclaves your dishware into immaculate sanitation. Which in a way it is, but given how much bacteria is literally everywhere after the cleaning it is just as effective as washing your dishes by hand.
Also need to note the overreaction that we have a society now to the concept of bacteria. There is bacteria literally everywhere. It's great that someone just used a dishwasher to remove all the bacteria from their plate, but the moment they touch that plate they're transferring bacteria, the moment the dishwasher is opened guess what? Bacteria. As those plates sit in the cabinet... bacteria. Do normal food prep safety standards by keeping raw meats away from other things and washing raw meat surfaces before using it for anything else, or as goblinchief said just have separate cutting boards if you're that worried. Outside of that it is okay to be exposed to these things, you already are.