I just want to start this off by clarifying that I absolutely do wash my hands often, throughout the day. In addition to regular cases of hand-washing, like during cooking, or after using the bathroom, the nature of my job also causes me to wash my hands frequently.
But I’ve been wondering what it actually does. I’ve always assumed the point was to kill bacteria, but the more I learn, the less this makes sense.
Most soap is non-antibacterial, which is by design, because antibacterial soap kills all bacteria, not just the harmful bacteria you’re trying to get rid of. Antibacterial soap has its uses, but it’s not recommended to use as your daily hand soap.
Okay, so the soap doesn’t kill bacteria. It must be the hot water, right? You’re always told, from the time you’re a little kid, that hot water kills bacteria.
Except that doesn’t seem to be how it works in practice. In theory, yes, hot water kills bacteria starting at 149F. This is the minimum threshold; meaning at 148F, no bacteria is killed at all, and at 149F, bacteria starts to be killed, but still requires a 5 minute exposure time to effectively kill all bacteria. I don’t know a single person who washes their hands for 5 straight minutes. And this isn’t even to mention that the recommended max temperature for water heater manufacturers is only 120F-140F (at least in the US). That’s an entire 9-29 degrees below the minimum threshold.
So washing your hands at the highest possible temperature allowed by your water heater, for 5 straight minutes, still doesn’t kill any bacteria. On top of the soap that intentionally doesn’t kill bacteria either.
Am I missing something? Is killing bacteria not the point? Is the exfoliating effect from physically rubbing my hands together sufficient in getting rid of bacteria? That seems hard to believe. How is the raw chicken bacteria removed from my hand?