Periplaneta australasiae

Here's a philosophical problem for the modern age... You put your dirty dishes in your dishwasher, add dishwasher detergent, close the door and start a wash programme. When you open your dishwasher the following morning, you pull out the bottom rack and discover one or more distinctly drowned large Australian cockroaches, or, sometimes, various cockroach body parts. Question: are your dishes really clean?