After a week or two, your new sponge starts to smell funny. It smells sour, and it's kind of gross to continue using it on your dishes. Fortunately, there are many ways to keep your sponge smelling fresh even after long use; but first, what causes a sponge to smell sour?

Bad Bacteria in Sour Sponges

As you clean your dishes every day, bits of food get stuck in the pores of the sponge, providing nourishment for bacteria. When the food debris decompose, they release an unpleasant, sour odor. Some strains of bacteria are so tough that even detergents like your dishwashing soap can't kill them. In just three days, your sponge can already harbor millions of bacteria. Nasty strains like E. coli, Salmonella and Campylobacter can multiply in your sponge and cause food poisoning. Researchers have also found out that 1ml of water squeezed out of a kitchen sponge can have as much as 10 million bacteria. If your sponge is already quite stinky, then it could harbor even more.

Getting Rid of Sour Sponge Smell

The best way to avoid illnesses caused by dirty sponges is to regularly buy a new one. If you don't want to replace your sponge frequently though, at least make sure that you clean it properly. Here are different methods to clean your sponge.

Daily Sponge Maintenance

Don't just throw the sponge anywhere after using it. Prevent foul odor through these daily maintenance tips:

• Remove any remaining food particles from the sponge. You may run water on it or scrape bits of food from it using your fingers.
• Put a few drops of bleach on the sponge, squeeze, then run water on it again.
• Wring out the sponge repeatedly until almost no water drains from it. Bacteria love moisture, so the more moist your sponge is, the more it helps them survive.
• Store the sponge in a dry container where it can drain off any remaining liquid.

Cleaning Your Sponge in the Dishwasher

Another way to clean your sponge is by putting it in the dishwasher. Follow these steps to do this method correctly:

• Place the sponge into the utensil compartment of the next wash and dry cycle, and leave it there until the entire wash and dry cycle is over.
• Remove the sponge once the washer stops. According to researchers, the sponge should now have 99.9998% less bacteria in it.

Note: Check the instructions or websites of the manufacturers of the sponge and dishwasher first before doing this method. Some manufacturers and dishwasher repairmen don't recommend this method since parts of the sponge could come off and get stuck in the mechanism.

Sanitize Your Sponge with a Microwave

The microwave method is probably the most effective way to clean your sponge. Take note though that this method is only for sponges that don't contain any metal. If your sponge contains metal, go for other cleaning techniques.

• Wash the sponge with clean water, but don't allow it to dry.
• Put the sponge into the microwave, and set it for about two minutes. According to a study done by the United States Department of Agriculture (USDA), microwaving a sponge for about a minute significantly reduces the population of bacteria, molds, and yeasts more than other methods. Microwaving for two minutes kills 99% of all the germs in the sponge.
• Carefully remove the sponge from the microwave. You may use tongs as the sponge will be very hot.
• Store the the sponge in a dry container, and let it cool before using it again.

Important notes: The microwave method can result in serious burns and fire if you're not careful. Remember the following when sanitizing your sponge through this method:

• Do not squeeze the sponge right after taking it out of the microwave because this will cause severe burns.
• Never microwave a dry or slightly damp sponge. According to the UK Royal Society for Prevention of Accidents, microwaving a dry sponge can start a fire. Make sure your sponge is sufficiently wet before you put it inside the microwave.
• Do not microwave the sponge for more than five minutes because this might also start a fire.
• Some microwaves develop a stench that's hard to get rid of when sanitizing a mildewed sponge. If you don't want to risk your microwave smelling bad, use other cleaning methods.
• The steam and humidity inside the microwave loosen food particles and stains in the sponge. When the sponge is cool enough, you may use a paper towel to remove stains and food particles effortlessly.

Bleach to Kill the Bacteria

If you don't have a dishwasher or microwave, bleaching the sponge may be the best option for you. It's not as effective as the dishwasher and microwave method, but it still gets rid of plenty of germs. According to a study funded by the US government, this method only kills 37% to 87% of bacteria.

• Make a solution of 10% bleach.
• Soak the sponge in the solution for three minutes.
• Thoroughly rinse the sponge, and put it in a dry container.

Tips to Keep Your Sponge Smelling Sweet

People have different ways of maintaining the freshness of their sponges. Here are some sponge maintenance tricks that have worked well for other people; maybe they'll extend the life of your sponge, too:

• White vinegar treatment: Soak the sponge in half a cup of white vinegar for a few hours, rinse it thoroughly, then allow to dry. The acidity of the vinegar will kill a huge portion of the germ population and reduce the odor of the sponge.
• Overnight soaking: At the end of the day, wash the sponge thoroughly, then soak it in a mixture of bleach and soap. Let the sponge soak overnight, then wring it in the morning.
• Soak it in baking soda: Soak the sponge in two tablespoons of baking soda for about an hour. Rinse it in warm water, then allow to dry. Baking soda can also be used to clean dishes, sinks, mirrors, even barbecue grills.
• Dishcloth for raw meat juices: Do not use a sponge to clean up raw meat juices. Instead, use paper towels or a dishcloth to absorb the juices. If you're going to use a sponge, make sure that it's different from the one you use to wash your dishes. Also, clean the dishcloth or sponge properly to prevent bad odor.
• Buy germ-resistant sponges: Instead of buying a regular sponge, buy one that's germ-resistant. A germ-resistant sponge is especially made to keep killing bacteria even after hundreds of uses. Some people claim that it can reduce the amount of bacteria in a kitchen area by as much as 99%. Antibacterial soaps and disinfectants may also achieve a similar effect.
• Use several sponges: Use two or more sponges for your everyday cleaning tasks, so that a single sponge will have a longer drying time. It's best to use a different sponge for each dishwashing task after every meal.
• Lemon juice on your sponge: Add lemon juice to your bleach, soap, or baking soda solution before soaking the sponge. The lemon juice will reduce the foul odor of the sponge, and restore some of its freshness.
• Never use it on your cutting board: Your cutting board is one of the dirtiest things in the kitchen. Never clean your cutting board with a sponge because raw food particles will get stuck in its pores and promote bacterial growth. Use a dishcloth instead of a sponge to clean the cutting board.

Your dishes are only as clean as your sponge. If your sponge is stinky and a haven for germs, then your dishes will also harbor germs, and may cause illnesses like diarrhea and food poisoning. If a sponge smells too sour, don't even think about trying to salvage it. Just throw it away and buy a new one to avoid any health risks.