Why using a dishwasher is more sanitary than hand washing

from Hand Washing Versus the Dishwasher Real Simple | Apartment Therapy

In the July issue of Real Simple‘s print edition, a reader asks if hand-washing dishes gets them as clean as a dishwasher does.

To kill most of the bacteria on a dirty dish, water must reach a scalding 140° Fahrenheit. That temperature is easily reached in a dishwasher, but in a sink, it’s nearly impossible. Hot-water heaters are typically set at 120 degrees to prevent burns, and most people can’t stand to keep their hands in a stream of water that hot for more than a few minutes.