5 ms·

I desperately hope this is the case, but a quick google couldn't find a link. Do you happen to have a citation that you'd recommend? I say this as someone who i

I desperately hope this is the case, but a quick google couldn't find a link. Do you happen to have a citation that you'd recommend? I say this as someone who is a bit paranoid about hand cleanliness _and_ is very tired of cracked skin.

adkadskhj 6y ago
I too am a curious dry-skin person. I thought i had read something to the affect of the interaction between soaps and bacteria worked better in warm water than cold. I'll be really interested if i can avoid warm water.
igneo676 6y ago
https://meridian.allenpress.com/jfp/article/80/6/1022/200017/Quantifying-the-Effects-of-Water-Temperature-Soap https://meridian.allenpress.com/jfp/article/80/6/1022/200017... Beyond the citation though, it makes logical sense. The mechanism for sanitation is that the soap itself destroys the bacteria. This mechanism works regardless of temperature. Cold water + Soap should be just fine as long as your hands are otherwise visibly clean. In the food industry, we were required to use high temperature water. This was presumably to remove actual surface contaminants (dirt, grease, other food contaminants) rather than for actual sanitation. That's why you might still see guidelines for using hotter water temperatures.
- vkou 6y ago
  Does soap actively destroy bacteria, or does it mostly wash the oils off your hands, that bacteria are stuck to/are covered by, and send them down the drain? I've always been taught it's the latter. Soaping your hands, and not rinsing will not sanitize them, you'll just end up with dirty, soapy hands.
  - clairity 6y ago
    most bacteria have an outer lipid layer that is clung to by the hydrophobic end of soaps and pulled apart by the hydrophilic forces clinging to water on the other end.
    - lazide 6y ago
      Additionally, the soap itself is binding to oils (which often frees up dirt if it was trapping in or under an oily layer, which being hydrophobic will stop water from washing the dirt off). Soap itself doesn’t do a whole lot against dirt.
tasogare 6y ago
It’s bit ridiculous to ask for a citation for something as simple as washing hands. You could try for yourself during a week and see if it change something.
- mattkrause 6y ago
  Just to play along here....how do you propose that they check whether the cold water removes bacteria more effectively?
  - Zircom 6y ago
    They were referring to difference between hot vs cold water and it drying out your skin, not the effectiveness of cold vs hot water at sanitizing.
    - mattkrause 6y ago
      I read the "paranoia about cleanliness" bit as suggesting both.
e12e 6y ago
> I desperately hope this is the case, but a quick google couldn't find a link. Do you happen to have a citation that you'd recommend? Cdc agrees: https://www.cdc.gov/handwashing/faqs.html https://www.cdc.gov/handwashing/faqs.html > Is it better to use warm water or cold water? > Use your preferred water temperature – cold or warm – to wash your hands. Warm and cold water remove the same number of germs from your hands. The water helps create soap lather that removes germs from your skin when you wash your hands. Water itself does not usually kill germs; to kill germs, water would need to be hot enough to scald your hands. Soap helps break down/encapsulate/dissolve oils/fat that aren't readily soluble in just water.
- lazide 6y ago
  Which, that breakdown and encapsulation happens faster at higher temperatures - it’s a pretty predictable chemical process. At scalding hot or higher temps, the surfactants can sometimes break down or form weird side products though.
  - e12e 6y ago
    It does happen faster at higher temperatures, but apparently not so much that it makes a difference in terms of cleaning your hands. I'm a bit surprised by that, but that's what studies seem to imply.
    - lazide 6y ago
      Do you have a link to the studies? I definitely notice a huge difference in washing with soap in cold water (camping), which is hard to not leave a film, and warm water which does a pretty effective job quite quickly with the same exact soap.
      - e12e 6y ago
        I didn't encounter any good primary sources, but a few references that seemed to indicate no difference in bacteria reduction between warm/cold water for washing hands. It may be that cold water is simply good enough.
ajmurmann 6y ago
https://onlinelibrary.wiley.com/doi/full/10.1046/j.1471-5740.2002.00043.x https://onlinelibrary.wiley.com/doi/full/10.1046/j.1471-5740... via http://foodsafetytalk.com/food-safety-talk/2012/6/25/food-safety-talk-20-im-not-worried-about-eating-my-own-poop.html http://foodsafetytalk.com/food-safety-talk/2012/6/25/food-sa...

adkadskhj 6y ago

I too am a curious dry-skin person. I thought i had read something to the affect of the interaction between soaps and bacteria worked better in warm water than cold. I'll be really interested if i can avoid warm water.

igneo676 6y ago

https://meridian.allenpress.com/jfp/article/80/6/1022/200017/Quantifying-the-Effects-of-Water-Temperature-Soap https://meridian.allenpress.com/jfp/article/80/6/1022/200017... Beyond the citation though, it makes logical sense. The mechanism for sanitation is that the soap itself destroys the bacteria. This mechanism works regardless of temperature. Cold water + Soap should be just fine as long as your hands are otherwise visibly clean. In the food industry, we were required to use high temperature water. This was presumably to remove actual surface contaminants (dirt, grease, other food contaminants) rather than for actual sanitation. That's why you might still see guidelines for using hotter water temperatures.

vkou 6y ago
Does soap actively destroy bacteria, or does it mostly wash the oils off your hands, that bacteria are stuck to/are covered by, and send them down the drain? I've always been taught it's the latter. Soaping your hands, and not rinsing will not sanitize them, you'll just end up with dirty, soapy hands.
- clairity 6y ago
  most bacteria have an outer lipid layer that is clung to by the hydrophobic end of soaps and pulled apart by the hydrophilic forces clinging to water on the other end.
  - lazide 6y ago
    Additionally, the soap itself is binding to oils (which often frees up dirt if it was trapping in or under an oily layer, which being hydrophobic will stop water from washing the dirt off). Soap itself doesn’t do a whole lot against dirt.

tasogare 6y ago

It’s bit ridiculous to ask for a citation for something as simple as washing hands. You could try for yourself during a week and see if it change something.

mattkrause 6y ago
Just to play along here....how do you propose that they check whether the cold water removes bacteria more effectively?
- Zircom 6y ago
  They were referring to difference between hot vs cold water and it drying out your skin, not the effectiveness of cold vs hot water at sanitizing.
  - mattkrause 6y ago
    I read the "paranoia about cleanliness" bit as suggesting both.

e12e 6y ago

> I desperately hope this is the case, but a quick google couldn't find a link. Do you happen to have a citation that you'd recommend? Cdc agrees: https://www.cdc.gov/handwashing/faqs.html https://www.cdc.gov/handwashing/faqs.html > Is it better to use warm water or cold water? > Use your preferred water temperature – cold or warm – to wash your hands. Warm and cold water remove the same number of germs from your hands. The water helps create soap lather that removes germs from your skin when you wash your hands. Water itself does not usually kill germs; to kill germs, water would need to be hot enough to scald your hands. Soap helps break down/encapsulate/dissolve oils/fat that aren't readily soluble in just water.

lazide 6y ago
Which, that breakdown and encapsulation happens faster at higher temperatures - it’s a pretty predictable chemical process. At scalding hot or higher temps, the surfactants can sometimes break down or form weird side products though.
- e12e 6y ago
  It does happen faster at higher temperatures, but apparently not so much that it makes a difference in terms of cleaning your hands. I'm a bit surprised by that, but that's what studies seem to imply.
  - lazide 6y ago
    Do you have a link to the studies? I definitely notice a huge difference in washing with soap in cold water (camping), which is hard to not leave a film, and warm water which does a pretty effective job quite quickly with the same exact soap.
    - e12e 6y ago
      I didn't encounter any good primary sources, but a few references that seemed to indicate no difference in bacteria reduction between warm/cold water for washing hands. It may be that cold water is simply good enough.

ajmurmann 6y ago

https://onlinelibrary.wiley.com/doi/full/10.1046/j.1471-5740.2002.00043.x https://onlinelibrary.wiley.com/doi/full/10.1046/j.1471-5740... via http://foodsafetytalk.com/food-safety-talk/2012/6/25/food-safety-talk-20-im-not-worried-about-eating-my-own-poop.html http://foodsafetytalk.com/food-safety-talk/2012/6/25/food-sa...