The NPR story recommends the option for food prep - as does Food Network Host Bob Blumer and author Lisa Casali. But it's important to note that, according to Food Safety News(FSN), appliance manufactures like General Electric and and Whirlpool advise against.
Why? Well, the appliance-makers say you should use it "only for its intended function." FSN says there's also a question of whether dishwashers heat up the food enough to kill pathogens such as Salmonella enteritidis and clostridium botulinum. Foods like poultry, beef, pork and fish need to be heated to the 145 to 160 degree range to be safe to eat.
Casali, who wrote a cookbook on the subject of dishwasher cooking, told FSN Electrolux representatives told her that the dishwashers she used while researching for her book reach 131-167 degrees F.
So while feelings may be mixed on making dinner in the dish racks - folks who go for it may want to keep a reliable thermometer on hand.