[igneo676]

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]

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]

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]

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.