And that is part of the problem.
“Because of their construction, sponges provide harborage for any number and variety of microbiological organisms, many of which may be pathogenic,” according to the Food and Drug Administration’s U.S. Food Code, a nonbinding document intended as a model for state and local governments when enacting their own regulations in retail and food service settings. In addition to food-borne pathogens, yeasts and molds can proliferate in sponges.
“The majority of people don’t know how to properly handle a sponge when it comes to the maintenance of it,” says Jason Bolton, extension professor and food safety specialist at the University of Maine Cooperative Extension.
Here’s what you need to know about caring for, cleaning and replacing your sponges.
How to clean and sanitize the sponge. Bolton says it’s essential to clean and sanitize your sponge regularly, ideally every day. You can do that through either heat or chemical means. First, wash the sponge with warm water and soap. The easiest next step is to microwave it on high for 1 minute. Make sure the sponge is still wet — too dry and it can catch on fire — and does not contain any metallic elements, such as in the scrubber, that can spark. (Be sure to pay attention to the manufacturer’s instructions, too, as not all brands recommend microwaving.) Let the sponge cool before handling, as it will be hot.
His other preferred method after washing is to soak the sponge in a bleach solution. Because the formula for diluting bleach can vary according to the product, the surface in question and what you’re trying to disinfect, Bolton says to check the label instructions for the bleach. Assuming your bleach is 8.25 percent sodium hypochlorite, you’ll need 1/4 to 1/2 teaspoon per quart of warm water. Soak the sponge in that solution for 1 minute.
The Agricultural Research Service, part of the USDA, found that a dishwasher with a drying cycle was almost as effective as microwaving, killing 99.9998 percent of bacteria on a sponge, as opposed to the 99.99999 percent in a microwave. Bolton is less sold on the dishwasher because dishwashers can vary in temperature and because of the potential fire or other hazard should the sponge come in contact with a heating element in the appliance. But if the sponge is secure and you’re confident about the temperature, go for it.
I’d also point you to this handy piece from NPR for a little context on various headlines you may have seen about how much may be living in your sponge. The key takeaway: Properly sanitizing will kill the problematic bacteria that can make you sick.
Other care and maintenance tips. Moisture is one of the requirements for potentially harmful bacteria to multiply, and that matters because it’s easy to let your sponge sit around wet. In between uses and cleaning, be sure to wring out whatever water you can. Store the sponge in a clean spot that allows for air circulation and reduces the possibility of cross-contamination, so not in the sink basin or even the dish rack, Bolton says. My mom has a clean soap dish devoted to the task, but you can also buy a dedicated sponge holder.
After testing various models, America’s Test Kitchen recommends looking for a holder with a large opening for dropping the sponge into, as well as an open construction to allow for efficient drying. It should attach securely enough to the sink to not be easily knocked off in the course of cleaning, which is where a slim profile comes in handy, too. ATK’s winning model, from SunnyPoint, features two large suction cups, while one of its runners-up from Yamazaki hangs from the faucet, useful if suction cups are not compatible with your sink material. Whatever you choose, ATK suggests cleaning the holder with hot, soapy water at least once a month.
Replacing. It’s hard to recommend a hard-and-fast rule for how often to replace a sponge, because much depends on how often it’s used and how it’s maintained, Bolton says. “If you use it seldomly, you could get two weeks out of it,” is his rough guidance. It’s important to pay attention to the condition of the sponge. If the sponge is torn, losing pieces or separating between the scrubber and soft side, it’s time to get a new one. Bolton notes that if you are properly sanitizing your sponge, the process will start to break it down anyway, which is a helpful built-in reminder. Another tell: “Once a sponge starts to smell, throw it out immediately,” advises the Iowa State University Extension and Outreach.
Ditch the sponge altogether. In commercial settings, the U.S. Food Code does not recommend using sponges on surfaces that have been cleaned, sanitized or are at that moment in contact with food. Instead, it suggests, in conjunction with various cleaners and abrasives, such items as scouring pads and brushes, which, of course, may not be compatible with some types of cookware. Bolton strongly recommends against using a sponge to clean equipment and surfaces that have been in contact with raw meat or fish, which can create cross-contamination problems. In those scenarios, he recommends using a disposable sponge or a rag that can be used once and put immediately in the washing machine to be cleaned with detergent and hot water (a more eco-friendly alternative to paper towels). You can use clean kitchen towels for the rest of your dishwashing, too.