Speaker 1: Welcome to brain Stuff from How Stuff Works. Hey, brain Stuff,
Speaker 1: it's Christian Seger. It's good hygiene to wash your hands
Speaker 1: after using the restroom and after touching kind of gross stuff,
Speaker 1: you know, like raw meat, snakes, cat litter, cats, biomedical waste,
Speaker 1: and any number of shared surfaces from door knobs to countertops.
Speaker 1: But what about soap? Bars of soap are also shared surfaces.
Speaker 1: So how dirty is soap? Soap is absolutely seething with bacteria,
Speaker 1: But you know, so is your face, and so so
Speaker 1: is my face and everything we come into contact with
Speaker 1: all day, every day. Really, organism for organism, microbes outnumber
Speaker 1: humans on the planet at least a hundred and thirty
Speaker 1: one quintillion to one. Sell for sell, The microbes in
Speaker 1: and on our bodies outnumber us ten to one, and
Speaker 1: human hands can have up to one hundred thousand micro
Speaker 1: organisms per square centimeter of skin. Most of them are
Speaker 1: harmless or you know, even helpful, but yeah, there's a
Speaker 1: lot of them, and some of them get transferred to
Speaker 1: your soap. One study from reported that of the bar
Speaker 1: soaps they tested, two tocent cultured positive for micro organisms.
Speaker 1: The antibacterial soap they tested actually had a bit more
Speaker 1: microbial activity than regular soap. The soaps in question were
Speaker 1: in use by the staff of clinics and laboratories over
Speaker 1: the course of seven days, and samples were taken on
Speaker 1: five of those days. But the interesting and comforting part
Speaker 1: of their results is that the microbes didn't build over
Speaker 1: the course of that week. Organisms would appear and disappear
Speaker 1: with each sample taken, indicating one of two things. Either
Speaker 1: the soaps were somehow self sterilizing, possibly due to preservatives
Speaker 1: they can tane that are you know, not delicious or
Speaker 1: downright dastardly to microbes, or the little buggers were being
Speaker 1: mechanically removed during the process of washing, meaning that as
Speaker 1: you wash your hands, you're also washing your soap. These
Speaker 1: results back up a couple of other studies about microbes
Speaker 1: and hand washing, one from ninety and one from The
Speaker 1: former study had subjects come into their lab, douse a
Speaker 1: hand in a vat of bacteria, and then wash with
Speaker 1: a bar of soap. The soap was tested for the bacteria,
Speaker 1: then given to another subject to assess the transfer of
Speaker 1: the bacteria. The latter study carefully doused bars of soap
Speaker 1: with ecle i and had subjects come in and first
Speaker 1: sterilized their hands, then wash them with this gross soap.
Speaker 1: The researchers then tested both the hands and the soap
Speaker 1: for microbes. Both of these studies found that although bacteria
Speaker 1: remained on the soaps, none transferred to the participants hands.
Speaker 1: Now here's the thing to note. These studies were done
Speaker 1: by employees of Procter and Gamble and Dial Corporation, respectively,
Speaker 1: and the first study I mentioned that one from that
Speaker 1: was completed with a grant from Minnatonka Incorporated, which was
Speaker 1: the original maker of soft soap. That doesn't necessarily mean
Speaker 1: their science was bad, though experts say there's no evidence
Speaker 1: to contradict their results. So bar soap is not underty,
Speaker 1: but it's still safe to use and way better than
Speaker 1: not washing. So here's a few pro tips. Be sure
Speaker 1: to dry your hands thoroughly after washing. Don't wash more
Speaker 1: often than necessary. That can lead to parched skin, which
Speaker 1: can crack, which can let in microbes. You otherwise would
Speaker 1: have been able to just wash off. And make sure
Speaker 1: you store bar soap in a dish that lets it
Speaker 1: drain and dry out between uses. That'll cut down on
Speaker 1: any potential bacterial growth. Check out the brainstuff channel on YouTube,
Speaker 1: and for more on this and thousands of other topics,
Speaker 1: visit how stuff Works dot com.