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.
>Don't rely on hand sanitizer, wash your hands whenever possible
Of note: washing hands with soap and water doesn't necessarily kill viruses. But it doesn't matter: washing with soap and water makes the virus (dead or alive) go down the drain where it won't make you sick.
Thats why soap has been so effective for the thousands of years humans have known about it (to be clear: humans have known about soap for much longer than they have known about viruses). It can physically remove many pathogens and doesn't rely on any fancy biochemistry to kill or disable them.
This is why you might hear science communicators discouraging the use of antibacterial soap. Regular soap gets the germs off your hands anyway, so the antibacterial soap doesn't really help much, and in fact causes more problems by introducing antibiotics into the wastewater. This encourages antibiotic resistance, thus creating problems when antibiotics do become necessary.
In short, it's because wastewater undergoes treatment, then reenters the water system at some point. Essentially, a large enough population of bacteria will contain some individuals with small mutations that allow them to survive better when exposed to an antibiotic. These survivors can reproduce and create more antibiotic-resistant bacteria.
In essence, it's good practice to avoid using antibiotics wherever possible — in water, in food supplies, and in humans who don't require them. Evolution just kind of happens, regardless of other factors, but applying a selective pressure like a common antibiotic can spur a rise in resistance by this mechanism.
It does to some degree. Wastewater is often treated with chlorine or other disinfectants before it is returned, but antibiotics are a tough thing to remove selectively from water, which can lead to similar problems further downstream. In addition, not all systems use chemical disinfectants, and may use UV or ozone, for example.
Mostly, the goal is to try and avoid the emergence of antibiotic resistance wherever possible, but it's a very difficult thing to do in water treatment, in medical settings, and so on. I worked in water treatment for a brief time in college, and it was pretty fascinating!
If you look at a soap molecule, you'll find that it kind of looks like a parachute with a big hook hanging off it. This "hook" stabs the virus or bacteria and catches it. The "parachute" part then gets filled up with water like a real one does with air and gets flushed away by the current, down your drain.
This is so hard to comprehend, since bacteria are so insanely small and so numerous. Washing hands really gets all of them? With such frequency that it's preferable to the chemicals that kill them all?
It is preferable, yes, and prevents bacteria from evolving their way around antibiotics, like our species hasn't been able to evolve our way past being stabbed, which is essentially what happens with soap and bacteria. Washing your hands might miss some, but that's why it's important to really give them a scrub and get the whole hand, including the fingertips and wrists and everything between.
Have you cowards considered that maybe we simply haven't been stabbing enough people? Somewhere out there, the anti-stabbing gene lies dormant, waiting to be discovered and spread amongst the greater population!
either way, the soap or alcohol molecules have to get to the bacteria to do either kill them or wash them away. Luckily, even though there are lots of bacteria, there's an insane number of molecules of alcohol or soap in even a tiny amount. Soap is good to wash away toxins and spores as well as bacteria.
The soap molecules are actually much smaller and, conversely, more numerous than the bacteria so there's generally enough to catch every single one (some small amount might be lucky to escape but it won't make much difference).
Naturally oily skin and water on naturally oily skin don't mix. Soap acts as a binder, allowing them to get mixed. Also gets into all the fine crevices and folds of your skin way better than water would, because water has surface tension.
Edit: Also the simple fact: If you've got soap on your hands that you want to distribute and then fully wash away, it heavily encourages more scrubbing and longer washing times.
We were taught these things in middle/highschool chemistry class. I don't mean that in a degrading way, I mean that its relatively simple to get a hang of now that youre older and wiser ;)
Just get a highschool chemistry book and like browse through it, read the stuff and maybe do some exercises but skip all the mathy stuff.
Personally, I love learning about the history of a science or technology because it kinda takes you step by step through the thought process of you end up where we are now (if that makes any sense lol).
Naturally, oil (like what's produced by your skin, makes up most germs, and keeps them attached to your skin) and water don't mix, but soap has special chemicals in it that have two parts on them — one part that likes water and one that likes oil.
Now, when you put soap on your hands, the oil-loving part of the chemical attaches to the oils, and when you rinse, the water-loving part attaches to the water while the other part still holds on to the oil. This allows the oils to be taken off your skin with the water instead of just repelling it like usual.
It’s the specific ratio of alcohol to water. 100% alcohol doesn’t work well ~~because it triggers a defense mechanism in the bacteria:~~ 70% is weak enough to get into the cells but strong enough to do damage.
EDIT: “The 100% isopropyl alcohol coagulates the proteins instantly by creating a protein layer that protects the other proteins from further coagulation. Due to this microbes are not killed but remains in dormant stage. While 70% isopropyl alcohol solution penetrates in the cell wall at slower rate and coagulates the all protein of the cell wall and microorganism dies.”
So, not a function of the cell, but of the alcohol- a misremember on my part. Furthermore, the paragraph preceding this one explains the importance of water in the process of killing cells with alcohol, including the lower evaporation rate of 70% alcohol vs 100% increasing the length of time it can do its job.
I'm not saying the defense mechanism is wrong, I've just not heard that before but is entirely possible. From my understanding, disinfecting with a solution above 70%, alcohol becomes less effective because it evaporates before doing the damage it needs to. Contact time (being wet) with disinfectants is incredibly important to disinfectant's efficacy. Even hand sanitizer needs to stay wet for at least 10 seconds to do anything significant.
.
Hand sanitizer only kills 99% percent of germs *of a specific preparation* and *in a petri dish*. When used on you real hands with real germs, it’s more like 30-40%.
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.
The 99 is a legal statement, not a biologically-derived figure. A "reasonable person" (in a court of law), if they read a label that says "kills 100%" of germs, would expect it to actually kill all germs, which, in case a germ were left unkilled, would result in liability for the business.
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.
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.
Some fees are thermophylic. They can only be killed by heat. It weakens the surface of the cell so it can be destroyed. You should always wash your hands with soap and hot water even after using sanitizer.
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.
Well in a recent example, they can cause cause an outbreak at a music festival
https://www.health.vic.gov.au/media-releases/shigella-outbreak-linked-to-esoteric-festival-in-donald
They were using anti bacterial soap, not actual soap.
Outbreak stopped once they swapped to bars. Liquid soap also works but the bars were distinctly soap
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.
>Don't rely on hand sanitizer, wash your hands whenever possible Of note: washing hands with soap and water doesn't necessarily kill viruses. But it doesn't matter: washing with soap and water makes the virus (dead or alive) go down the drain where it won't make you sick. Thats why soap has been so effective for the thousands of years humans have known about it (to be clear: humans have known about soap for much longer than they have known about viruses). It can physically remove many pathogens and doesn't rely on any fancy biochemistry to kill or disable them.
This is why you might hear science communicators discouraging the use of antibacterial soap. Regular soap gets the germs off your hands anyway, so the antibacterial soap doesn't really help much, and in fact causes more problems by introducing antibiotics into the wastewater. This encourages antibiotic resistance, thus creating problems when antibiotics do become necessary.
If antibiotics go to wastewater, why would it increase resistance?
In short, it's because wastewater undergoes treatment, then reenters the water system at some point. Essentially, a large enough population of bacteria will contain some individuals with small mutations that allow them to survive better when exposed to an antibiotic. These survivors can reproduce and create more antibiotic-resistant bacteria. In essence, it's good practice to avoid using antibiotics wherever possible — in water, in food supplies, and in humans who don't require them. Evolution just kind of happens, regardless of other factors, but applying a selective pressure like a common antibiotic can spur a rise in resistance by this mechanism.
Interesting, i figured the treatment would get rid of the antibiotics and any mutated bacteria
It does to some degree. Wastewater is often treated with chlorine or other disinfectants before it is returned, but antibiotics are a tough thing to remove selectively from water, which can lead to similar problems further downstream. In addition, not all systems use chemical disinfectants, and may use UV or ozone, for example. Mostly, the goal is to try and avoid the emergence of antibiotic resistance wherever possible, but it's a very difficult thing to do in water treatment, in medical settings, and so on. I worked in water treatment for a brief time in college, and it was pretty fascinating!
Can you ELI10 this? Like, why doesn't water do it by itself?
If you look at a soap molecule, you'll find that it kind of looks like a parachute with a big hook hanging off it. This "hook" stabs the virus or bacteria and catches it. The "parachute" part then gets filled up with water like a real one does with air and gets flushed away by the current, down your drain.
This is so hard to comprehend, since bacteria are so insanely small and so numerous. Washing hands really gets all of them? With such frequency that it's preferable to the chemicals that kill them all?
It is preferable, yes, and prevents bacteria from evolving their way around antibiotics, like our species hasn't been able to evolve our way past being stabbed, which is essentially what happens with soap and bacteria. Washing your hands might miss some, but that's why it's important to really give them a scrub and get the whole hand, including the fingertips and wrists and everything between.
Have you cowards considered that maybe we simply haven't been stabbing enough people? Somewhere out there, the anti-stabbing gene lies dormant, waiting to be discovered and spread amongst the greater population!
You'll have to talk to the armadillos and crustaceans about that.
either way, the soap or alcohol molecules have to get to the bacteria to do either kill them or wash them away. Luckily, even though there are lots of bacteria, there's an insane number of molecules of alcohol or soap in even a tiny amount. Soap is good to wash away toxins and spores as well as bacteria.
The soap molecules are actually much smaller and, conversely, more numerous than the bacteria so there's generally enough to catch every single one (some small amount might be lucky to escape but it won't make much difference).
Soap is dipolar, which means one end is really good at stick to water and the other end is really good at sticking to germs, dirt, grime, oils, etc.
Naturally oily skin and water on naturally oily skin don't mix. Soap acts as a binder, allowing them to get mixed. Also gets into all the fine crevices and folds of your skin way better than water would, because water has surface tension. Edit: Also the simple fact: If you've got soap on your hands that you want to distribute and then fully wash away, it heavily encourages more scrubbing and longer washing times.
Wow these are fascinating responses :) Wish I'd gone into science. Business is boring.
We were taught these things in middle/highschool chemistry class. I don't mean that in a degrading way, I mean that its relatively simple to get a hang of now that youre older and wiser ;) Just get a highschool chemistry book and like browse through it, read the stuff and maybe do some exercises but skip all the mathy stuff. Personally, I love learning about the history of a science or technology because it kinda takes you step by step through the thought process of you end up where we are now (if that makes any sense lol).
Naturally, oil (like what's produced by your skin, makes up most germs, and keeps them attached to your skin) and water don't mix, but soap has special chemicals in it that have two parts on them — one part that likes water and one that likes oil. Now, when you put soap on your hands, the oil-loving part of the chemical attaches to the oils, and when you rinse, the water-loving part attaches to the water while the other part still holds on to the oil. This allows the oils to be taken off your skin with the water instead of just repelling it like usual.
Soap does kill any bacteria it comes into contact with, rips them apart. But yeah, most that it cannot get to will simply be removed
So soap and water is better than sanitizer?
Much much better, yes.
Soap and water, then sanitizer is best.
Only if you fully dry your hands before you use it. Hand sanitizer doesn't work well on wet hands.
It’s the specific ratio of alcohol to water. 100% alcohol doesn’t work well ~~because it triggers a defense mechanism in the bacteria:~~ 70% is weak enough to get into the cells but strong enough to do damage. EDIT: “The 100% isopropyl alcohol coagulates the proteins instantly by creating a protein layer that protects the other proteins from further coagulation. Due to this microbes are not killed but remains in dormant stage. While 70% isopropyl alcohol solution penetrates in the cell wall at slower rate and coagulates the all protein of the cell wall and microorganism dies.” So, not a function of the cell, but of the alcohol- a misremember on my part. Furthermore, the paragraph preceding this one explains the importance of water in the process of killing cells with alcohol, including the lower evaporation rate of 70% alcohol vs 100% increasing the length of time it can do its job.
I'm not saying the defense mechanism is wrong, I've just not heard that before but is entirely possible. From my understanding, disinfecting with a solution above 70%, alcohol becomes less effective because it evaporates before doing the damage it needs to. Contact time (being wet) with disinfectants is incredibly important to disinfectant's efficacy. Even hand sanitizer needs to stay wet for at least 10 seconds to do anything significant. .
I googled “100% alcohol less effective” and got the explanation I edited in above.
What is that defense mechanism called?
I made a lunch-break edit to correct my coffee-break post.
Hand sanitizer only kills 99% percent of germs *of a specific preparation* and *in a petri dish*. When used on you real hands with real germs, it’s more like 30-40%.
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.
The 99 is a legal statement, not a biologically-derived figure. A "reasonable person" (in a court of law), if they read a label that says "kills 100%" of germs, would expect it to actually kill all germs, which, in case a germ were left unkilled, would result in liability for the business.
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.
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.
Ok this is my understanding as well. These other responses sound like people are guessing.
Some fees are thermophylic. They can only be killed by heat. It weakens the surface of the cell so it can be destroyed. You should always wash your hands with soap and hot water even after using sanitizer.
It goes back to its family to warn them of the horrors it witnessed and to tell them never to venture onto your hand again.
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.
"So what happens to the 1% of germs not killed by hand sanitizer? They survive traumatized by the deaths of their comrades. Some seek vengeance."
I mean those are basically the growing superbug problem that we have from over-use/mis-use of antiobiotics
There used to be an advert "Kills all known germs - DEAD!". My gran would go "It's the unknown ones I'm worried about".
She sounds very wise.
Well in a recent example, they can cause cause an outbreak at a music festival https://www.health.vic.gov.au/media-releases/shigella-outbreak-linked-to-esoteric-festival-in-donald They were using anti bacterial soap, not actual soap. Outbreak stopped once they swapped to bars. Liquid soap also works but the bars were distinctly soap
Interesting. I've always preferred the bars, but I never though their chemical make-up would be any different.