Microwaves Useful for Sterilizing Kitchen Sponges

Scientists at the University of Florida discovered a quick and easy way to eliminate many of the bacteria, viruses, parasites and spores in the average kitchen by sterilizing household sponges in a microwave oven.

The scientists soaked sponges and scrubbing pads in untreated wastewater containing faecal bacteria, viruses, protozoan parasites and bacterial spores including Bacillus cereus spores which are quite resistant to radiation, heat and toxic chemicals. They also used bacterial viruses as substitutes for disease-causing viruses, such as hepatitis A.

Two minutes of microwaving on full power mode killed or inactivated more than 99 percent of all the living pathogens in the sponges and pads. The Bacillus cereus spores required four minutes for total inactivation.

Unclean sponges may seem like a small problem, but more than 76 million people are sickened by food poisoning each year in the U.S., and approximately 5,000 of those cases are fatal, according to the Centers for Disease Control and Prevention.

Many can be traced to household kitchens where unsanitary dishcloths and sponges abound. Cleaning these items in the dishwasher doesn't kill the germs they harbor.

The sponges must be wet prior to heating them up, or the process could cause a fire or damage the ovens. Some individuals who were eager to try out the process after reading initial reports of the findings placed dry items in their microwaves with disastrous results -- including the destruction of both sponges and ovens and, in some cases, nasty odors that lingered for hours.