How Bad Is it if I Don't Use Soap When I Scrub a Dish?

Ah, friends. They're like family but cooler. Fully customizable. Fall and one of them will be right there to pick you back up. But as great as friends can be, they also do a lot of really stupid stuff. Stuff that blows your mind. Like, sometimes it seems crazy that you even hang out with people who make such crappy decisions. Stuff that, were it to get out, would be mortifying for anyone with even a shred of self-respect. Lucky for your friends, they've got you to ask their deepest, darkest questions for them. And lucky for you, we started this column to answer those most embarrassing of queries. The scenario: A while back, your friend watched the Netflix documentary on minimalism and it really hit him hard. Among other things, he's since ditched that "frivolous" soap that was taking up too much space on the counter. And when it comes to clearing out the kitchen sink post-meal, he's adopted a total barebones practice: Just rising his fine Ikea china with plain 'ol H2O until all the grime has disappeared. If it looks clean, it must be clean, right?

Why it's bad: Though his Kondo-ing is enlightening—namaste and prayer hands emoji—less is unfortunately not more when it comes to dishwashing, unless the "more" you are referring to is bacteria and diarrhea. But first, let's discuss the role of soap in the situation: "Soaps have compounds that kill bacteria and others that lift food from the surface so it can be rinsed away," says Melvin Pascall, a professor of food science and technology at Ohio State University. Sans suds, bacteria from foods that were either not cooked properly or that was just on the food to begin with—things like E.coli, Salmonella, staphylococcus, campylobacter, and norovirus, also known colloquially as "winter vomiting bug"—are just left hanging out. And the lingering meal left behind on the dishes isn't great either. When dishes crusted with food particles (even if it's the tiniest ones), sit out, they become a friendly surface for contaminants to cling to and multiply, says Guy Crosby, associate adjunct professor at the Harvard School of Public Health and science editor at America's Test Kitchen. Bacteria double in population every four to 20 minutes, so it doesn't take a long time before there are millions of things ready to tear apart the digestive tract.

What can he get away with: As your friend (maybe) knows, bacteria are microscopic, so it's hard to know what he'll be dealing with—he's not going to see all the little E. Coli swimming around on a plate—but there could be some explanation for why he's not yet experienced explosive consequences. Since the water supply in the US is generally safe, Crosby thinks you can maybe get by rinsing a water glass that you've been using in just water if only you have used it and plan to keep it to yourself. Sharing makes things complicated, because now if someone else—who also happens to have the stomach flu—takes a sip and it's not washed properly (soap and hot water), you could get stuck with that, depending on how contaminated it is, Pascall says.

"Also, acidic foods like tomato sauce, vinegars, and salad dressings have a lower pH," Crosby adds," so they're less susceptible to the growth of bacteria, and thus less likely to get contaminated."

But it's definitely not worth the gamble if he's been handling meat or eggs—especially raw ones and especially raw chicken—which tends to be more moist and have a higher pH. That makes it the perfect habitat for bacteria and other pathogens to call home, Crosby says. Again, not all food will have bacteria, but a Consumer Reports experiment found E. Coli in 65 percent of the 316 chicken breasts they tested, and at least one multi-drug resistant bacterium in about half of them, so, ugh, science is not on his side.

What's the worst that could happen: Well, if the contamination is serious and there's a lot of pathogens, he could die. No, for real. Crosby says that some encounters with Clostridium botulinum bacteria can be fatal. This microbe is most commonly found in the soil, so if you're cutting up unwashed fruits and vegetables, and then not washing the dishes properly, it can get kind of dicey. Clostridium botulinum produces a neurotoxin that, even in microscopic amounts, can lead to symptoms like double vision, difficulty breathing, and paralysis. Stuff like E. Coli and Salmonella can give him unpleasant symptoms like upset stomach, bloody stools, vomiting, and diarrhea. Fun!

Not to mention, "if you don't clean properly, you risk cross-contaminating to other utensils, sponges, hands, countertops, and dishes," says Crosby. Maybe he scrambled those eggs to the CDC-recommended 160 degrees which would kill all the bad stuff, but if he beat the raw yolks in a bowl that was just rinsed and the eggs happened to have Salmonella, that can now make it's way to the pan. So your friend is basically creating a whole pathogen orgy in his sink. What to tell your friend: Invest in the damn soap already. It's like, $5, which is the cost of one of his daily cold brews. To clean your dishes, both Crosby and Pascall suggest lathering up with soap and rinsing with at least warm, or even better, hot water. Items like cutting boards, which have grooves, and stainless steel—where bacteria can survive up to four days!—should be scrubbed more vigorously.

If your friend has a dishwasher, let that machine be his savior. "They're faster, more consistent, and rinse it at higher temperature, which is good for killing bacteria," says Pascall. Bonus: It's even more virtuous. A 2009 study found that hand washers used up to 27 gallons of water and 2.5 kilowatt-hours (kWh) of energy to wash 12 place settings, compared with the 4 gallons and 1.5 kWh used by an efficient dishwasher to wash the same amount.

If his dishwasher is relatively new, it can actually save him more money and conserve more water and energy since newer models are constantly being improved to be more effective, according to the EPA's Energy Star Program. Sidestepping death and saving the planet? His street cred just got so much stronger.