Cleaning

How Hot Does Your Water *Actually* Need to Be to Clean Dishes?

April  4, 2018

The house rules were simple: My mom or dad cooked dinner, my sister and I washed dishes. And almost every night we’d fight about the water temperature. I wanted to push the faucet as hot as it would go, turning my hands bright pink and pots and pans squeaky clean. My sister couldn’t handle the heat, and every time she presided over the sponge, my mom would call us back to rewash greasy bowls.

Eventually, we learned the best way to tackle the task (and keep bickering to a minimum) was a further division of labor—my sister loaded the dishwasher and put away leftovers, while I handled handwashing at the sink. But recently, as I was rewashing dishes my roommate had cleaned the night before (she's another lukewarm water fan), I found myself wondering: Have I taken this too far? Am I losing friends and alienating people by pushing them away from the sink? What if I don’t really need very hot water?

Curious, I contacted Dr. Pritish Tosh, Infectious Diseases Physician and Researcher at the Mayo Clinic (and an avid home cook!). What I learned mildly horrified me: my water wasn't hot enough.

“To completely sanitize something, you need to wash in 150°F water for 20 minutes," Tosh told me. "The human body can’t withstand that," but it is something your dishwasher can do.

Since many of us are the only dishwashers in the kitchen, Tosh had some tips to clean by hand.

  • Wash dishes with soap and use as high of a temperature as you can stand.
  • Keep two separate sponges, one for cleaning items that have touched raw meat and one for everything else.
  • More importantly, avoid cross contamination. A sponge is a moist area that—because it has been in contact with food, a nutritional source for bacteria—is a prime location for bacteria like salmonella to thrive.
  • Use enough soap to create a lather, and make sure to clean every part of the item (like the handles).
  • Clean as you cook to avoid bacteria drying and sticking onto utensils as biofilm.

Oh, and don’t keep either of those sponges around for too long: “Once they smell funky, throw them out,” he says.

That’s a new simple rule I can follow. And I can't wait to tell my sister.

How much heat can you handle in the kitchen? Are you as surprised as I am?

15 Comments

cascadian12 April 10, 2018
Great article, because it's exactly how I wash dishes at home. I use very hot water and those dishwashing gloves if I remember to put them on. I'm pretty sure I'm sanitizing dishes because they dry almost immediately. I wash all surfaces with soap (Dawn because of de-greasing capabilities) and a sponge. Since the sponge is used and rinsed out well several times a day, they actually last a long time. Then I rinse everything under running hot water, as hot as I can stand, until everything feels squeaky clean. No oils or fingerprints left! I can't stand fingerprints on glasses or anywhere I can see them. I've had a succession of housemates over the years and only one of them knew how to wash dishes properly in all that time, and only because both of her parents were "professional" dishwashers.. Because of all the other housemates, I've always insisted on doing the dishes.
 
Carey J. July 31, 2018
This looks like a canning blog, lol. “My grandma always just scraped the mold off and we all never got botulism”. Um, we evolve, sanitation practices are for our safety. I bet the lady who brought potato salad from her potatoes “canned in the oven”, had never had botulism before. She killed herself and a couple other church members unlucky enough to partake of her salad.
 
witloof April 6, 2018
Totally agree with cupcakemuffin. I have never gotten sick from eating food I have cooked at home and you wouldn't believe how long I keep my sponges and forgo the dish soap altogether. Being worried about maintaining a fully sanitized kitchen at home when you're cooking for healthy people is just nonsense. We have immune systems! They're good at what they do.
 
AntoniaJames April 6, 2018
Yes, witloof, so true. Research shows that getting rid of as many germs in our environments as we can is actually not good for our health. See, e.g., https://www.kqed.org/mindshift/48729 (focus on dirt and kids) ;o)
 
Author Comment
Katie M. April 6, 2018
Hi witloof! Thanks for your input, and glad you haven't been sick! I'm thankful for a pretty hardy immune system, too ;)
 
witloof April 7, 2018
Katie, forgive me, but publishing articles like this seems irresponsible to me. You're encouraging people to be afraid of something that there is no reason to worry about and to use up more resources and more energy in order to kill bacteria and microbes that we can take of ourselves naturally and which may actually be good for us.
 
Smaug April 4, 2018
Hot water heaters shouldn't be set to more than 120 degrees. The idea isn't to kill germs, it's to wash them down the drain; hot water rinses better and feels better on cold mornings, that's why you use it. A lot of bacteria actually thrive at water heater temps. If you're worried about bacteria, use a rag instead of a sponge and put it in the wash after you use it. The real secret is not to put dangerous microbes in your food; there's no particular reason why your dishes should be swarming with bacteria anyway, anymore than your counters or the air around you. Recent advice in a national column to turn up the heat on your water heater if your dish washer isn't getting them dry enough is among the most irresponsible things I've ever seen in an advice column.
 
AntoniaJames April 6, 2018
i agree with everything you say here, Smaug. Thank you! ;o)
 
Charlie S. April 4, 2018
How hot would you want the water to be at a restaurant? Just sayin'
 
Smaug April 4, 2018
I believe they generally use steam.
 
Charlie S. April 4, 2018
Hi-temp machines wash, with water, at 150 to 160 and rinse at 180 (all *F). Low-temp machines have to use chemical sanitizers.
 
cv April 5, 2018
Ask the local authorities.<br /><br />Here in California, food safety regulations are basically determined by the county.<br /><br />Restaurants are inspected by county health inspectors and must meet certain clearly defined standards. That includes water temperatures at different points in the cycle.<br /><br />That said, this blog post is about household dishwashing strategies, so your comment is rather puzzling.<br /><br />Remember, restaurant dishwashing appliances run really short cycles, like 3-5 minutes. Their devices must accomplish a certain list of tasks that a household machine might take 2 hours to accomplish. Restaurant dishwashing machines don't have to deal with plates that sit for three days encrusted with food.<br /><br />Run the machine with hot enough water and you don't really need a drying cycle either.<br /><br />Very difficult to compare restaurant and residential dishwashing machines.
 
cupcakemuffin April 4, 2018
Ok, but who cares if your dishes are actually sanitized? I agree if things are still greasy, that's gross, but otherwise a few extra germs seem...fine? Of course if you're someone who is immunocompromised you may want to take these extra steps (or just get a dishwasher), but for your average person I just don't see the point. I have never gotten food poisoning from a poorly washed dinner plate in my own home!
 
Author Comment
Katie M. April 6, 2018
Hey cupcakemuffin! I totally understand—I definitely don't sanitize all my dishes! I think Dr. Tosh's main concern is raw meat contaminating non-cooked foods, which make sense because he studies infectious diseases and bacteria. I was surprised to learn it required such high temperatures to kill bacteria and felt like it was worth sharing :)
 
Catou November 9, 2018
I appreciate katie’s investigation and consulting an ID Dr. for her answers....<br />I was doing a search for appropriate temps because I have an immunocinpromised child and was looking for that very information. <br />Something else I do just to be thorough is add bleach to rinse water and soak sponges daily in bleach. However, I rely mostly on dishcloths and switch them out daily.