By

Caitlin A. Johnson /

CBS/ February 11, 2009, 5:25 PM

Microwaving Sponges Might Not Kill Germs

A recent study published in The Journal Of Environmental Health found that microwave ovens can kill 99 percent of the germs harbored by kitchen sponges. But Sharon Franke, kitchen technology and appliances director at Good Housekeeping Research Institute is skeptical.

"We don't recommend that people do it," she told The Early Show co-anchor Harry Smith. "They take the risk that their sponge will not be sanitized. It's a false security."

Kitchen sponges are the No. 1 source of germs in the house and as many as 80 million Americans contract food-borne illnesses each year — 9,000 of those Americans die.

While the simplicity of the microwave method makes it very attractive, Franke says there are many problems with this method and that results can vary depending on whether you're using a small or a big microwave or whether the sponge is wet or dry.

Franke said every microwave is different, so it's hard to tell which sponge will get hot in which microwave. For instance, it may take two minutes to kill germs in a big microwave but it could take four to six minutes in a smaller microwave.

She also said there is the chance that the sponge will overheat and catch on fire or be rendered useless. The only way to analyze it is would be to look in a sophisticated microbiological lab.

"I have this rule of thumb, if it smells, throw it out," Smith said.

If you want to be frugal, Franke said a good alternative is to sterilize a sponge with bleach. Add about a teaspoon of bleach to a cup of water, let the sponge sit in the mixture for five minutes, and then germs will be gone.

Franke recommended using an all-purpose antibacterial cleaner like Fantastic on a paper towel instead of a sponge when cleaning counter tops that may have bacteria on them.

"Wipe it up, throw the paper towel out and look for a cleaner that says antibacterial on it, spray the surface and let it stand for ten minutes," she said. "After 10 minutes you can rinse it off but you only get the benefits in 10 minutes."

She doesn't recommend putting the sponge in the dishwasher because there is no way to tell if it gets hot enough in the dishwasher to kill bacteria. If the bacteria isn't killed, it contaminates the things around it.
Copyright 2009 CBS. All rights reserved.
8 Comments Add a Comment
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53clipper says:
I think I will go by what the government tests found:
http://ddr.nal.usda.gov/bitstream/10113/23351/1/IND44126362.pdf

But these methods are only good if you did it like they did it.
Some people don't have their dishwashers set on a 'sani' cycle.
Some microwaves are not as powerful, so the sponges would need longer time. After hearing about sponges, and microwaves getting really stinky after doing it that way, I think I will pass!

I just feel better with the old standby, putting a teaspoon of disinfecting bleach in a cup of water and soak the dickens out of it.
Beware, not all bleaches are labelled "disinfecting".

Let's all be careful, and not get the dreaded 'collywobbles".
That means making sure your food is brought up to 165 deg. before eating, too.
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bthiel5 says:
Clorine bleach causes artificial sponges to decay. Why not just boil them for 5 minutes?
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linfinster says:


I'm sure Fantastic, 409 and Clorox are somehow tied to the network and this is a good way to get advertisement. I'll take my chances that 99% is good enough. Has been so far.
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krazykodama says:
Can't we just boil our sponge in a pan? Like for 10 minutes in a boiling water?
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duncan97304 says:
In reference to the segment on disinfecting sponges you ran this morning. I've owned a cafe for almost 26 years and have taken many food-handlers classes as mandated by our county health department. What I've learned is that the correct amount of bleach to water to use as a disinfecting solution is one tablespoon of bleach per one gallon of water (or 3/4 of a teaspoon of bleach to one quart of water). If you use too much bleach it looses it's disinfecting properties.
Sincerely,
Duncan Fraser
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drsweener says:
Also, it annoys me that CBS would put that headline up as if what she says is fact. One woman refusing to accept a study sheds doubt? If a scientific study debunked the first, then use the word "might" until more studies can be done to explain the phenomenon.
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drsweener says:
There isn't any research to back her claims. The original article is supported by a scientific study. Her claims are supported by intuition. This not being the middle ages, I'll go with the scientific study.
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sheikha-2009 says:
Instead of taking the chance with a kitchen sponge, either buy a new one every other week or just use a washcloth that can be washed and reused. That is much cheaper in the long run that using sponges or papertowels. Also, I don't agree with the use of antibacterial cleaners, they breed super-germs. You can do more with white vinegar and baking soda, or even a non-chlorine bleach with better results.

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