Now we kitchen sponge users have a second way to sterilize our cleaning tool: The dishwasher with a drying cycle.
Scientists from the Agricultural Research Services performed an experiment to determine which normally used household methods for cleaning reusable sponges worked.
At the ARS Food Technology and Safety Laboratory in Beltsville, microbiologists Manan Sharma and Cheryl Mudd and two student interns did the testing. First, they soaked sponges at room temperature for 48 hours in a solution made from ground beef and lab growth medium to attain a high level of microbes (20 million per sponge) to simulate a very dirty sponge.
Then, they treated each sponge in one of five ways: soaked for three minutes in a 10 percent chlorine bleach solution, soaked in lemon juice or deionized water for one minute, heated in a microwave for one minute, placed in a dishwasher operating with a drying cycle—or left untreated.
The scientists chose these methods because they're commonly used in most household kitchens. They found that between 37 and 87 percent of bacteria were killed on sponges soaked in the 10 percent bleach solution, lemon juice or deionized water—and those left untreated. That still left enough bacteria to potentially cause disease.
Microwaving sponges killed 99.99999 percent of bacteria present on them, while dishwashing killed 99.9998 percent of bacteria.
Science you can use.