When you use our lovely little bars of lemon or lavender hand soaps on the rim of a sink, you know they are there to make you feel as fresh as a gardenia-scented daisy. We all know washing our hands is important but, like washcloths and towels, can the bars of hand soap we use to clean ourselves become dirty as well?
Is it safe to use in a shared office ? can we switch from liquids ? will we swap germs ? ........we answer all of these questions below
Soaps are simply mixtures of salts derived from fatty acids and alkali solutions during a process called saponification. Each soap molecule is made of a long, non-polar, hydrophobic (repelled by water) hydrocarbon chain (the "tail") capped by a polar, hydrophilic (water-soluble) "salt" head. Because soap molecules have both polar and non-polar properties, they're great emulsifiers, which means they can disperse one liquid into another.
When you wash your dirty hands with soap and water, the tails of the soap molecules are repelled by water and attracted to oils, which attract dirt. The tails cluster together and form structures called micelles, trapping the dirt and oils. The micelles are negatively charged and soluble in water, so they repel each other and remain dispersed in water—and can easily be washed away.
So, yes, soap does indeed get dirty. That's sort of how it gets your hands clean: by latching onto grease, dirt and oil more strongly than your skin does. Of course, when you're using soap, you're washing all those loose, dirt-trapping, dirty soap molecules away.
This doesn't seem to be much of a problem, though. In the few studies that have been done on the matter, test subjects were given bars of soap laden with E. coli and other bacteria and instructed to wash up. None of the studies found any evidence of bacteria transfer from the soap to the subjects' hands. (It should be noted that two of these studies were conducted by Procter & Gamble and the Dial Corp., though no contradictory evidence has been found.)
Furthermore there is no evidence from any major studies we know of that “anti-bacterial” soaps with Triclosan shows any noteworthy differences to that of plain bar soap.
A bar of soap gets cleaned via the same mechanical action that helps clean you up when you wash your hands: good old fashioned scrubbing. Studies have shown just one and a half turns under running water is all you need to clean the bar, The friction from rubbing your hands against the soap, as well as the flushing action of running water, removes any harmful microorganisms from both your hands and the soap and sends them down the drain – Voila !
Antibacterial studies :
Allison E. Aiello, Elaine L. Larson, Stuart B. Levy
Clinical Infectious Diseases, Volume 45, Issue Supplement_2, 1 September 2007, Pages S137–S147, https://doi.org/10.1086/519255
Published: 01 September 200701 September 2007