Can’t Take Back-teria What You Said

, , , , , , | Learning | November 16, 2019

Back in third or fourth grade, we had someone come into our class for a special science lesson. They had petri dishes, swabs, and an incubator, and immediately after recess, they asked us to swab our hands and wipe the swab on a petri dish. Then, we were told to wash our hands with a bar of soap they brought in — the usual liquid soap was off-limits for some reason — and then re-swab our hands for another petri dish. We then labeled both dishes, put them in the incubator, and came back the next day to look at the results.

Almost everyone had more bacteria on their hands after washing them. The exceptions were two girls who “probably scrubbed enough to remove most of the bacteria physically.” It was explained that certain types of bar soap were actually decent places for bacteria to live, and that denying us the liquid soap was a trap. The presenter then went on to talk about some of the colonies of bacteria on the slides and some interesting or rare ones, as well as which ones might be dangerous.

So… that’s the story of why I stopped using all soap for over a decade — and still prefer liquid soap over bar soap. In my defense, I was young and may have missed the point of the presenter. On the other hand, he was giving a presentation to young children on how washing your hands with soap can actually add bacteria. Why would you ever think that is a good idea?

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