ELI5- what happens to the 1% of germs not killed by hand sanitizer?
In: Biology
Those germs are hiding underneath or inside the natural oil of your skin, they’re inside your pores, under your fingernails – basically anywhere the alcohol can’t get to. It will continue to live and reproduce, slowly increasing its numbers once more.
Other germs like norovirus actually have a “shell” called a capsid which cannot be penetrated by hand sanitizer, so they are “immune” to it. These germs just… continue to hang out on your hand, unbothered.
Don’t rely on hand sanitizer, wash your hands whenever possible.
There’s no guarantee that a small number of germs will survive every application of sanitizer. They put as many 9s on the package as they can legally justify based on some tests they’ve conducted, and they’ll never say 100% in case someone finds one surviving germ one day.
If a germ survives by luck, for example you didn’t hit every area or leave it on long enough, it keeps doing its thing.
If it survives by biology, for example it’s slightly more resistant to whatever chemical you applied, maybe the next generation will have some germs that are slightly more resistant than that, and you’re well on the way to breeding a germ that can is resistant to the treatment.
Natural selection. The ones that live have something which allowed them to survive the sanitizer. This trait gets passed on. And on. And on.
Evolution.
Your immune system handles it. Just about everything you touch is covered with mold spores and bacteria but most aren’t bad for us. it’s when you don’t wash properly after pooping and wiping or handling raw meat from the grocery store that you can get sick from what’s on your hands.
Same as that percentage of fecal matter on your toothbrush that everyone ignores. Your body handles it.
It’s just a bit of covering their backsides. By claiming 99% that’s very nearly almost all. 100% would be too difficult to prove, so they can’t claim it. What if one germ survived? That’s not 100%, and therefore opens the company to the risk of making false claims or false advertising. By claiming 99% the risk of accusation if making false claims is much reduced.
It’s also why one famous bleach brand long claimed to kill 99% of all “known” germs. Can’t later be sued if the product doesn’t kill a germ that wasn’t previously known.
There used to be an advert “Kills all known germs – DEAD!”. My gran would go “It’s the unknown ones I’m worried about”.
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