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How does liquid hand soap work?


Eed
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I've heard that antibacterial soap is no better than ordinary soap. Can someone please explain how ordinary liquid hand soap works? Does it simply help take off debris, or does it break the cells of bacteria and viruses and therefore render them harmless (kill them)?  For example, if someone washed their hands with liquid hand soap but let's just say they didn't wash all of the physical debris off, are the germs left on their hands still considered to be harmful? Thanks

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Simple answer, yes. The soap is to help you remove attached debris, along with the pathogens. Note how long and how rigorous hospital theatre staff clean their hands and arms. The mechanical aspect of washing hands and how long you do it  is very important.

Edited by StringJunky
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40 minutes ago, Eed said:

I've heard that antibacterial soap is no better than ordinary soap. Can someone please explain how ordinary liquid hand soap works? Does it simply help take off debris, or does it break the cells of bacteria and viruses and therefore render them harmless (kill them)?  For example, if someone washed their hands with liquid hand soap but let's just say they didn't wash all of the physical debris off, are the germs left on their hands still considered to be harmful? Thanks

Soap, being a surfactant, tends to disrupt the bi-lipid membranes which form the cell walls of bacteria and the viral envelope. So yes it breaks them open.  So far as I know, there is no special property of liquid hand soap as opposed to other kinds of soap. Soap in general works this way. Clearly though, it is best to rinse off whatever is dislodged from the surface of your hands.  

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2 hours ago, StringJunky said:

Simple answer, yes. The soap is to help you remove attached debris, along with the pathogens. Note how long and how rigorous hospital theatre staff clean their hands and arms. The mechanical aspect of washing hands and how long you do it  is very important.

Thank you StringJunky for getting back to me.

 

2 hours ago, exchemist said:

Soap, being a surfactant, tends to disrupt the bi-lipid membranes which form the cell walls of bacteria and the viral envelope. So yes it breaks them open. 

Thank you. This is what I was hoping to hear more about. So, when the bacteria and virus cells are broken open, they are no longer considered harmful?

I remember when the pandemic first started, I was seeing posters in bathrooms that said washing hands "killed" the virus (they weren't specifying antibacterial or regular soap). That made me question how the act of washing hands would kill the virus (because prior to that I believed that regular soap simply washed the germs away (without killing them), while antibacterial soap actually killed and washed them away).

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How does handwashing with soap and water remove germs and chemicals?
Soap and water, worked into a lather, trap and remove germs and chemicals from hands. Wetting your hands with clean water before applying soap helps you get a better lather than applying soap to dry hands. A good lather forms pockets called micelles that trap and remove germs, harmful chemicals, and dirt from your hands.

Lathering with soap and scrubbing your hands for 20 seconds is important to this process because these actions physically destroy germs and remove germs and chemicals from your skin. When you rinse your hands, you wash the germs and chemicals down the drain.

https://www.cdc.gov/handwashing/faqs.html

 

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14 minutes ago, Eed said:

I remember when the pandemic first started, I was seeing posters in bathrooms that said washing hands "killed" the virus (they weren't specifying antibacterial or regular soap). That made me question how the act of washing hands would kill the virus (because prior to that I believed that regular soap simply washed the germs away (without killing them), while antibacterial soap actually killed and washed them away).

Degrades would be a better term than killed.

 

Somewhere backalong in the probably thousands of posts we have had on the pandemic, was one of mine where I posted the UK government explanation that the covid virus has a middle portion that is 'fatty'.

Soap, or any detergent, attacks that fatty portion causing the virus complex to braeak up.

This is not necessarily true of all viruses or bacteria).

One thing I remember during my one year of microbiology (not my best subject) was the 'rate of extinction (killing) 'curve'.

Actually it was a % rather than a rate, but it shows that the % extinction increases with time of exposure, partly due to the protection effect afforded by outer layers of a colony or individual.

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I was under the impression the point of soap was to make your hands too slippery for germs to cling to, and therefore have them all leave your hands, where they could have been harmful, and go down the drain into the methane-producing sewers, where they could be made useful. (Provided your infrastructure is designed to harvest the methane, of course.)

 

Besides, what's stopping bacteria from evolving to survive "antibacterial" soaps like they did with antibiotics? in theory the point would be moot among those who wash their hands thoroughly enough, but antibacterial-soap-resistant antibiotic-resistant bacteria in a venue where sewer workers have to deal with them sounds like a recipe for disaster if sewer workers' protective clothing punctures...

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50 minutes ago, ScienceNostalgia101 said:

I was under the impression the point of soap was to make your hands too slippery for germs to cling to, and therefore have them all leave your hands, where they could have been harmful, and go down the drain into the methane-producing sewers, where they could be made useful. (Provided your infrastructure is designed to harvest the methane, of course.)

 

Besides, what's stopping bacteria from evolving to survive "antibacterial" soaps like they did with antibiotics? in theory the point would be moot among those who wash their hands thoroughly enough, but antibacterial-soap-resistant antibiotic-resistant bacteria in a venue where sewer workers have to deal with them sounds like a recipe for disaster if sewer workers' protective clothing punctures...

Sewer workers have been known to eat their meals where they are working. They might wear wellies and rubber gloves and helmet, but that's about it for safety gear. I get the impression you think they work in a biohazard suit... no. They do have vaccinations for diseases they may be exposed to.

Edited by StringJunky
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53 minutes ago, ScienceNostalgia101 said:

I was under the impression the point of soap was to make your hands too slippery for germs to cling to, and therefore have them all leave your hands, where they could have been harmful, and go down the drain into the methane-producing sewers, where they could be made useful. (Provided your infrastructure is designed to harvest the methane, of course.)

 

Besides, what's stopping bacteria from evolving to survive "antibacterial" soaps like they did with antibiotics? in theory the point would be moot among those who wash their hands thoroughly enough, but antibacterial-soap-resistant antibiotic-resistant bacteria in a venue where sewer workers have to deal with them sounds like a recipe for disaster if sewer workers' protective clothing punctures...

First of all, that is not how soap works. Others have already mentioned the correct role of soap. Biogas production from sewage is done in specialized systems which encourages the growth of methanogens. They do not harvest skin bacteria to do that.

As already mentioned, soap is more of an abrasive and, as a detergent, has general physical properties (i.e. disruption of lipids) as opposed to antibiotics which target highly specific molecules (e.g. a specific ribosomal subunit or enzyme). As the mechanisms are so different and unspecific, it it is rather difficult to develop resistance against it. It is a bit like trying to become resistant against a sledgehammer to the head.

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