Microwave oven - A cheap way to keep kitchen germs free

A microwave oven is of course renowned for cooking or heating the food but the appliance that cooks food by means of high-frequency electromagnetic radiation can also help in keeping bacteria away from taking over kitchen, a team of environmental engineers from the University of Florida reported on Monday.

Working as a sterilizer, this kitchen device sanitizes the household sponges and plastic scrubbers, known to be common carriers of the bacteria and viruses that cause food-borne illnesses, with its microwave radiations rapidly and effectively, meaning that people can use their microwaves as an inexpensive and effective weapon against E.coli, salmonella and other bugs at the root of increasing incidents of potentially deadly food poisoning and other illnesses.

In their study, published this week in the American Journal of Environmental Health, the U.S. researchers have said that two minutes in a microwave can sterilize sponges and dishcloths after use, killing more than 99 per cent of the harmful bacteria that cause illness.

"Basically what we find is that we could knock out most bacteria in two minutes. 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," said lead author Gabriel Bitton, a professor of environmental engineering at the University of Florida.

To reach at their conclusion, the researchers soaked sponges and scrubbing pads in raw wastewater water that contained fecal bacteria such as E. coli, viruses, protozoan parasites and bacterial spores, including Bacillus cereus spores and compared their findings with water from control sponges and pads not placed in the microwave.

After heating up the sponges in a common household microwave oven, they found that except the bacterial and Bacillus cereus spores, which required between four to ten minutes to destroy, everything else was killed after two minutes. Similar to many other bacterial spores, Bacillus cereus spores are completely resistant to radiation, heat and toxic chemicals, and are unfavorably known for difficult to kill.

Professor Bitton, who is an expert on wastewater microbiology, said that the technique could also be used to decontaminate syringes, however, emphasized that it took up to 12 minutes in a microwave oven to kill the Bacillus cereus spores on a needle. At the same time, he suggested that the sterilization time can be shortened by placing the syringes in heat-trapping ceramic bowls.

According to data provided by the U.S. Centers for Disease Control and Prevention, at least 6 million Americans get sick from food borne microbes every year, and at least 9,000 people die from them. The food-borne illnesses are accountable for $4 billion to $6 billion medical costs and other expenses.

In a house, kitchen is a common source of contamination, probably 200 times more germ-infested than a lavatory seat, as pathogens from uncooked eggs, meat and vegetables find their way onto countertops, utensils and cleaning tools. Earlier studies have given the evidences of sponges and dishcloths providing happy home for millions of the pathogens, in part because they often remain damp, which helps the bugs survive.