Kitchen Sponge| How often you should change it| Curio Facts

 How old is that sponge you're using to clean your dishes, to wipe down your counters and to sop up spilled messes

Boy, it truly is an all-purpose tool, isn't it?

If you can't remember, it's probably time to toss it and use a new one. That's because, according to the first comprehensive study on the topic, your kitchen sponge is disgusting. And the only way to fix that is by throwing it out and start with the fresh one

Can you smell what your sponge is cooking?

For a study published in the Nature journal Scientific Reports, researchers led by Markus Egert of Furtwangen University in Germany sequenced the microbial DNA in 14 used kitchen sponges to figure out exactly what kind of bacterial situation they had on their hands. They also tagged breeding microbes with fluorescent markers so they could watch them using special imaging techniques.

They hit the motherlode: Out of more than 223,000 DNA sequences, the sponges came back with 362 different types of bacteria. In fact, they found that a single cubic centimeter could be packed with more than 5x10 raise power 10 bacteria.

Most of the bacteria weren't harmful. The samples were dominated by the bacteria Moraxellaceae, which is found all over human skin and kitchens. It's responsible for the sour smell of laundry

But some of the bacteria were harmful. Five of the 10 bacteria most commonly found in the sponges were potential pathogens. Even worse, those nastier bacteria were found in higher percentages in sponges that had been regularly sanitized. That makes sense when you think about it: If popping a sponge in the dishwasher or microwave kills 99 percent of the bacteria festering within it, that remaining 1 percent is by definition the toughest bacteria on the sponge — and now it's free to take over.

So now that you're thoroughly grossed out by that moist little rectangle moldering by the sink, what do you do about it?

The obvious but the difficult option is to stop using sponges altogether.

We suggest a regular replacement of kitchen sponges. For example, on a weekly basis. Next time you find yourself giving a sponge the sniff test, remember the old adage: When in doubt, throw it out