So Your Kitchen Sponge Is A Bacteria Hotbed. Here’s What To Do

Michaeleen Doucleff wrote . . . . . .

Back in August, a study came out about bacteria in kitchen sponges that sent home chefs into a frenzy.

But when we looked carefully at the study, we realized much of the news coverage about it was incorrect.

The study, published in Scientific Reports, undertook a thorough investigation into how many critters are living in used kitchen sponges. And the results were jawdropping.

“We found 362 different species of bacteria, and locally, the density of bacteria reached up to 45 billion per square centimeter,” says Markus Egert, a microbiologist at Furtwangen University in Germany, who led the study.

Forty-five billion microbes per square centimeter? Are you kidding? If you scale that up, that’s like stuffing all the people who live in Manhattan into the Rockefeller ice rink.

“That’s a very huge number of bacteria, indeed,” Egert tells NPR. “There’s hardly any habitat on Earth where you’ll find similar densities of bacteria, except for the human intestinal tract.”

In other words, there can be spots on your kitchen sponge with just as high concentrations of bacteria as in a toilet.

That result in itself is pretty remarkable. And it makes you think twice about using the sponge to wipe up your dining room table.

But that finding isn’t what got people riled up. Instead, it was a line in the study’s abstract: Two species of bacteria “showed significantly greater proportions in regularly sanitized sponges [compared to uncleaned sponges], thereby questioning such sanitation methods in a long term perspective,” the study says.

Then the media took this idea and ran with it.

“Your Kitchen Sponge Is Gross, and Cleaning It Isn’t Helping,” New York magazine’s headline read.

“Cleaning a Dirty Sponge Only Helps Its Worst Bacteria, Study Says,” The New York Times put it.

“Some people may think that microwaving a sponge kills its tiny residents, but they are only partly right,” the Times story continued. “It may nuke the weak ones, but the strongest, smelliest and potentially pathogenic bacteria will survive.”

After reading these stories, including one posted on NPR’s Facebook page, I started becoming a bit skeptical. Something smelled fishy here. This conclusion just didn’t fit with my firsthand experience as a scientist.

Back in 2007, I was a biochemistry postdoc slaving away in the lab. I spent many of those days growing huge flasks of bacteria closely related to food-borne pathogens. I fed them, harvested them, fished out their genes, studied their guts — and killed them — day after day after day.

Anyone who has worked with food-borne pathogens — or their close relatives — knows that these little critters aren’t “the strongest.” They are weaklings. You heat them up just a little bit and they literally pop!

“That’s why we cook food. We know that heating will kill the pathogens,” says Jennifer Quinlan, a food microbiologist at Drexel University.

So what in the heck is going on with this new sponge study? Are the findings upturning decades of public health recommendations?

Not at all, Quinlan says. The media reports were simply not accurate.

“After you contacted me for an interview, I read the study in great detail,” she says. “I feel now that the comments they make about not recommending washing in the abstract are really, really misleading.”

In fact, she says, you can’t draw any conclusions about the effect of washing sponges from this study.

For starters, there was no clear explanation of what “regular cleaning” meant, she says.

“What really irked me is that you had to go all the way into the supplemental material to find how people reported washing the sponges,” Quinlan says. “Even then the methods were very vague.”

The study stated that the sponges were either microwaved or put in hot, soapy water. The latter can actually make the sponge stinkier, Quinlan says.

“Nobody would recommend hot, soapy water as a way to disinfect a sponge,” Quinlan says. “That could actually encourage the bacteria.”

The study also looked at only five sponges that people said they “cleaned” regularly — and study participants did not say whether this cleaning took place in the microwave or in soapy water. “We do not want to make public health recommendations based on five sponges from Germany,” Quinlan says.

Instead, families should stick with the same recommendations Quinlan has given for years:

1. Keep the sponge away from raw meat. “If you’re dealing with raw juices from meat or poultry, you should be using paper that can be disposed of,” Quinlan says.

2. Don’t keep sponges around for too long. “I replace mine every one to two weeks,” she says. “That’s reasonable to me.”

3. Clean the sponge every few days. The USDA recommends putting it in the dishwasher with a heated dry cycle, or wetting the sponge and popping it in the microwave for a minute.

Microwaving the sponge will knock down the bacteria living in it by about a million-fold, scientists at the U.S. Department of Agriculture reported back in 2009. Of course, this method will leave many still alive since there are billions in the sponge. But the heat targets the dangerous ones, Quinlan says.

“It doesn’t sterilize the sponge,” she says. “But remember, the bacteria we want to kill are the ones that will make you sick.”

In the new study, cleaning apparently boosted the levels of two species. Egert has no idea exactly what these species are, but one is related to bacteria that give your dirty laundry that stinky, musty smell. The other is related to bacteria that, on rare occasions, cause infections in people with suppressed immune systems. Neither of these relatives are known to cause food poisoning.

Just five species of bacteria are responsible for more than 90 percent of hospitalizations due to food-borne illnesses. And these bacteria are actually quite rare in sponges, Quinlan says.

Egert and his team didn’t find any of these food-borne-illness-causing bugs in their 14 sponges. And in a study published earlier this year, Quinlan and her colleagues detected pathogens in only about 1 to 2 percent of sponges collected from kitchens in Philadelphia. Even then, the amount of the pathogens present was very small, her team reported in the Journal of Food Protection.

“So when you microwave the sponge,” she says, “it will likely get rid of them all” — if they are even there in the first place.

And then you can rest easy that washing the dishes will not make you sick.

Source: npr


Chart of the Day: Ranking of the Dirtiness of Objects in the Kitchen

Enlarge image . . . . .

Source: Business Insider

Kitchen Cooking Burns a Real Danger for Kids

The day she ended up with second- and third-degree burns on her back, 4-year-old Giuliana Maggio was just busy doing what 4-year-olds do: running around the house, playing hide-and-seek during a family gathering.

Giuliana never saw the electrical cord running from the wall to the hot slow cooker sitting on the kitchen table.

She ran into the cord, and pulled the scalding hot contents of the slow cooker on to her small body.

Fortunately, her mother is a registered nurse and knew she had to act quickly. The family called 911, and Dina Maggio immediately put her daughter in the shower to run cool water over the burned area.

“As the cold water ran over her, and clothing was removed, I could see the layers of skin coming off and knew it was bad,” Maggio said.

The little girl had second- and third-degree burns on her arms and lower back. She was taken to Loyola University Medical Center’s burn center for treatment.

“Almost 20 percent of Giuliana’s body was severely burned. But it could have been much worse if her mother had not acted quickly and correctly,” Dr. Anthony Baldea, a burn surgeon at Loyola University Medical Center in Illinois, said in a university news release.

Giuliana underwent surgery and spent two weeks in Loyola’s burn unit.

“Giuliana’s wounds continue to improve and the burned areas are healing well. We do not even expect to see any scarring,” Baldea said.

Unfortunately, this burn accident was not an isolated case.

Cooking burns are common among American children, but can be prevented with simple precautions, doctors say.

“The majority of our burn patients are children who are seriously injured in cooking- or food-related injuries,” Baldea said.

In 2011, an estimated 136,000 children were seen in U.S. emergency rooms for burn injuries, according to the American Burn Foundation. More than 1,100 children die each year from burn injuries, and the annual cost of scald injuries is $44 million.

Ways to protect children include establishing a “no kid zone” in the kitchen around stoves, ovens and other hot items. Also, make sure cords from appliances — such as slow cookers, deep fryers and coffeemakers — don’t dangle over the counter edge, Baldea said.

Place pots and pans on the back burners with handles turned away from the front of the stove, and keep anything hot on tabletops out of reach of young children.

If a child does suffer a burn, use cool — not cold — water to stop the burning process. Remove all clothing, including diapers from the injured area, Baldea advised.

Cover the burn with a clean dry sheet or bandages and seek medical attention immediately.

Source: U.S. Department of Health and Human Services

Cooking Class: Cutting Boards



If kindly treated, a maple cutting board can last at least 10 years before retiring gracefully to the kitchen wall as a chronicler of meals past. Wood has “give” and doesn’t dull blades as quickly as harder surfaces do. Many chefs prefer end-grain boards (those that look like checkerboards) because they’re firmer than edge-grain boards (those made with long strips of wood, like the one above) and stand up to restaurant use. For the home chef, however, end-grain boards are probably not worth the extra cost.


Despite what many people believe, wood does not contain a natural germicide that kills bacteria. It is not dishwasher-safe and must be oiled to prevent splits and cracks.


Scrub with a nonabrasive brush and hot, soapy water. Rinse and dry thoroughly—water that sits can create a germ-friendly environment. What’s more, when water is left to evaporate, the wood’s own moisture evaporates with it, which means you’ll have to treat your board with oil more frequently. You can tell the board needs to be oiled when its glue lines are extremely light. Use mineral oil or raw, all-natural tung or walnut oil, both available at most health-food stores. (Don’t use cooking oil—it can make the wood smell rancid.)

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Crafted from narrow, laminated bamboo strips, these boards have become popular for everyday cooking because they function just as well as hardwood boards without all the extra TLC. They’re lightweight and attractive enough to double as serving trays, and the hard surface means fewer nicks and slices that harbor bacteria.


Bamboo (which is a grass) is harder than wood, so it performs well, but your knives will need more frequent sharpening.


Compared with wood boards, bamboo won’t shrink or swell as much when exposed to water, and you won’t need to apply oil as frequently. Regular rinsing with warm water and mild detergent and an occasional sweep of mineral oil are enough to keep the sheen intact. With proper care, a bamboo board will last at least 10 years.

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Plastic and Solid Surface


These cutting boards are lighter than wood, generally dishwasher-safe, and kind to knives and will not stain or gouge easily. A solid-surface board (such as Corian) can withstand the heat of a hot pot. Softer plastic (for example, polypropylene) is less durable.


There aren’t many downsides to plastic. But even though studies have repeatedly proved that nonporous plastic is better than wood at preventing bacteria growth, you still must be vigilant about sanitizing.


Wipe away water as you chop. Afterward, scrub with a nylon brush and hot, soapy water, then rinse and dry thoroughly. Consider buying a board that is labeled “dishwasher-safe” so it will withstand the 140-degree heat of a rinse cycle. This will remove stains and germs embedded in slits and crevices.

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Disposable Cutting Sheets


These new kids on the chopping block can be thrown out after a single use, so they’re a blessing for picnickers and campers, as well as those who fear E. coli and salmonella.


Disposable sheets, made of paper and plastic, can slide around while you’re chopping, and they don’t stand up to heavy-duty jobs, such as cutting up a whole chicken. And like disposable diapers, they aren’t for the environmentally conscious.

CARE: Roll up and toss.

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Flexible Cutting Mats


These durable, place mat-thin plastic sheets are easy to store and bend, so you can transfer chopped foods without making a mess. Inexpensive and multicolored, they lend themselves to a system: yellow for poultry, green for produce, blue for fish, for example. Since you don’t have to worry about chicken juices contaminating the salad greens, you won’t need to stop and wash as you chop.


These mats are too thin and flexible to withstand the dishwasher. Use them on a resilient surface, like a butcher block, Corian, or a laminated counter (not stainless steel or granite), or your knives will take a beating. They are lightweight and may slide around while you cut (a damp paper towel set under the mat will keep it in place). Larger flexible mats—those that are at least 15 by 11 inches—stay put better.


Wash well with hot, soapy water. Dry thoroughly and store flat.

Source: Real Simple

Kitchen Utensils Can Spread Bacteria, Study Finds

Expert advises washing knives, peelers between each use on different types of produce.

Kitchen utensils such as knives and graters can spread bacteria between different types of produce, a new study finds.

University of Georgia researchers contaminated different types of fruits and vegetables with bacteria such as salmonella and E. coli. They cut the produce with a knife or shredded it with a grater, then used the unwashed utensils on other produce.

Both utensils spread the bacteria to other types of produce, the study found.

The researchers also found that certain types of produce contaminated knives to different degrees.

“For items like tomatoes, we tended to have a higher contamination of the knives than when we cut strawberries,” said lead author Marilyn Erickson, an associate professor in the department of food science and technology.

“We don’t have a specific answer as to why there are differences between the different produce groups. But we do know that once a pathogen gets on the food, it’s difficult to remove,” she said in a university news release.

Further testing revealed that brushes and peelers also transfer bacteria between produce.

Many people don’t know that kitchen utensils can spread bacteria, Erickson said.

“Just knowing that utensils may lead to cross-contamination is important,” she said. “With that knowledge, consumers are then more likely to make sure they wash them in between uses.”

The study results were published recently in the journal Food Microbiology.

Source: U.S. Department of Health and Human Services