Is having facial hair hygienic? Are they a ripe breeding ground for dangerous bacteria? Should bearded hippies be allowed to work in a microbiology laboratory?
A group of square microbiologists suspected that their bearded colleagues were a contamination risk due to their long facial hair and devised interesting experiments to test this. The experiments involved a lot of chickens, for some reason. Lu and Tirth discuss this groovy study on S01E05 of the Recreational Science podcast (timecode 22:52):
Tirth: I think it was the last episode where my magnificent beard was brought up. Listen, I put a lot of effort into this beard. I’m very proud of this. So, I found this study that I have some beef with, so to speak. The title of the study is, “Microbiological laboratory hazard of bearded men”.
Lu: Tirth this sounds like a serious question. I’m also very concerned about this.
Tirth: This study was published all the way back in 1967 in the journal Applied Microbiology, which I assume is a great journal.
Lu: Good journal. Very good journal.
Tirth: So, people who work in microbiological laboratories can unwittingly end up being carriers of infectious disease. Therefore, these scientists asked, well, is there something about beards? Specifically, they write, “after many years of absence from the laboratory scene, beards are now being worn by some persons working with pathogenic microorganisms”. Remember this is 1967, okay?
Lu: Ah, hippie culture. Everybody had beards and long hair.
Tirth: Exactly, so these scientists are concerned. They’re like, “hey what if beards can retain or hold onto microorganisms?”
Lu: What I’m hearing is that some very square scientists, who’ve never been offered a joint in their life, said one day, “let’s get them hippies. Let’s kick those hippies out of our lab, because they don’t shower, they’re spreading germs with their beards, and they don’t invite us to their parties.”
Tirth: Yes, and as I mentioned, they want to test two related questions. The first question is, does washing the beard make a difference? So if you’re a bearded man and you work in the lab, can you wash off most of the bacteria in your beard? The second question is, can beards contaminated with bacteria actually make animals sick?
Lu: Oh I see. This is of course to make sure that they’re following Koch’s postulate, the criteria of Koch’s postulate, which states that once you’ve identified a potential pathogenic organism, you should make sure it can infect other things before deeming it a pathogenic organism.
Tirth: Exactly. So to answer the first question, they inoculated the beards of four men with a couple of harmless bacteria, and then tested whether the bacteria grew in their beards a while later.
Lu: Mhm.
Tirth: They found that 3 out of the 4 guys had these bacteria growing in their beards.
Lu: Okay.
Tirth: And then they repeated the experiment, except this time, they had the four men wash their beards after inoculation with bacteria, and found that basically nothing grew.
Lu: Suggesting that washing the beard washed away or killed the bacteria present in the beards.
Tirth: Yes. And then they asked the four men to shave their beards and also added a fifth guy. They inoculated their clean-shaven face with the same bacteria and then tested whether the bacteria grew on their faces.
Lu: Wait, wait, the fifth guy they added was a bearded man who they made shave his beard? They couldn’t have just gotten an unbearded man to begin with?
Tirth: So it’s possible that the fifth guy was unbearded to begin with. They don’t mention it. But they found that the unwashed, clean-shaven face grew bacteria, but the washed face basically did not grow anything.
Lu: Okay, so just like the beards.
Tirth: Correct. And next they tested the second question, can infected beards make animals sick? They got a mannequin, put a fake beard on it, inoculated the fake beard with a virus, and rubbed chickens on the fake beard.
Lu: Okay, so they ran out of Petri dishes to grow bacteria. They’re like, hey, we have some chickens lying around. Let’s see if we can culture bacteria in the chickens.
Tirth: Yes, except it’s a virus in this case. And, they sound disappointed about this, but they found that the chickens didn’t really get sick. They also weren’t able to recover the virus from the chickens.
Lu: I see.
Tirth: However, when they inoculated the fake beards with higher doses of the virus, most of the chickens had some growth in a dose dependent fashion. So the higher the concentration of virus they used, the more they recovered from the chickens. However, if they washed the fake beards prior to rubbing chickens on them, they were unable to recover viruses from the chickens.
Lu: Okay. So what was their conclusion?
Tirth: Well, they acknowledge that beards might be okay in a microbiology laboratory as long as the people wash them after work.
Lu: I see. Not a trivial conclusion in the 60’s. But regardless, mission accomplished for the square scientists. It sounds like they successfully got 4 or 5 of their hippie colleagues to shave their dirty beards for this study.
Tirth: That’s right.
Article citation
Barbeito et al., 1967. Microbiological laboratory hazard of bearded men. Applied Microbiology. https://journals.asm.org/doi/10.1128/am.15.4.899-906.1967
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