Thor527 t1_iyddf2w wrote on November 30, 2022 at 3:53 PM

Reply to comment by sparklesandflies in ELI5: Why does stuff dissolve in hot water more? by samuelma

To add to this, unless the hand soap is anti microbial, hand washing generally doesn’t kill germs. As you said though it helps rinse them off your skin and temperature doesn’t make any difference beyond comfort unless it’s hot enough to really burn you.

Edit: I stand corrected, disrupting the membrane can kill some bacteria. I thought that was only true for some soaps and not all but I guess I was wrong.

TyrconnellFL t1_iydfl8q wrote on November 30, 2022 at 4:08 PM

That is wrong. Soap is very effective at disrupting cell membranes and destroys bacteria. The surface of cells, including many bacteria, is kind of like a bubble of fats. Not exactly days, but similar enough that soap does the same thing and dissolved it. Dissolve the surface of a cell and all the innards spill out. Now it’s not a living cell, it’s a collection of dead cell bits.

Soap will also detach many bacteria and let you wash them off, but soap itself is strongly antimicrobial. It doesn’t contain antibiotics and for most uses there’s no reason to add antibiotics. The same is true for alcohol hand sanitizer: it’s not antibiotic, but it’s lethal to cells.

IonizingKoala t1_iydnmvi wrote on November 30, 2022 at 5:01 PM

The FDA has found that anti-microbial soap is equally as effective as regular soap. But the main anti-microbial ingredients can actually be harmful to the environment, so it's worse if you care about the environment.

It's different in a hospital setting, I think they have some more unique reasons for needing to use anti-microbial soap.