Putting kitchen sponges and scrub pads in the microwave for two minutes can kill bacteria and viruses, eliminating the threat of food-borne illnesses, U.S. researchers say.

"People often put their sponges and scrubbers in the dishwasher, but if they really want to decontaminate them and not just clean them, they should use the microwave," lead researcher Gabriel Bitton, a University of Florida professor of environmental engineering, said in a release.

Bitton soaked sponges in wastewater containing fecal bacteria, viruses, protozoan parasites and bacterial spores. Researchers found that putting the sponges in the microwave for two minutes on full power killed more than 99 per cent of the living pathogens on the sponges.

The more resilient Bacillus cereus spores, which can cause diarrhea, needed to be zapped for four minutes to be killed.

In many cases, food poisoning can be traced back to improper hand-washing and refrigeration practices in the kitchen. Earlier studies have shown that damp sponges and dishcloths provide a livable environment for potentially harmful bacteria.

The study, published in the December issue of the Journal of Environmental Health, says the heat of the microwave kills the pathogens. Bitton notes that it's best to put the sponges in the microwaves wet for full effect.

Researchers suggested that excess water should be squeezed from the sponges and cautioned that metallic sponges or scrub pads should never be put in the microwave.