Microwaves the best sterilising agent in kitchen
Two minutes in a microwave oven can sterilise most household sponges, US researchers have reported.
A team of engineering researchers at the University of Florida found that two minutes of microwaving on full power killed or inactivated more than 99% of bacteria, viruses or parasites, as well as spores, on a kitchen sponge.
“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,” says Gabriel Bitton, a professor of environmental engineering who led the study.
Writing in the Journal of Environmental Health, Bitton and colleagues say they soaked sponges and scrubbing pads in raw wastewater containing faecal bacteria such as Escherichia coli, viruses, protozoan parasites and bacterial spores.
Then they used a common household microwave oven to heat the sponges. It took 4-10 minutes to kill all the spores but everything else was killed after two minutes, they say.
Spores of the food spoilage organism Bacillus cereus were the hardest to destroy.
“The microwave is a very powerful and an inexpensive tool for sterilisation,” says Bitton, who specialises in studying wastewater microbiology.
He says it’s the heat, rather than the microwave radiation, that probably kills the pathogens. Because the microwave works by exciting water molecules, it’s better to microwave wet rather than dry sponges.
