Sampling bacteria from phone and safety

Hi all,
I was looking at these videos on youtube where they show how to sample bacteria from phones or other sources. here’s an example

I was wondering if any of you have been doing any sampling and growing of bacteria from the body in a self-organised bioLab and what kind of safety measures did you take.
I talked with a microbiologist (with no background in DIY practices) and she told me it’s pretty dangerous even if you keep the petri dish sealed and she would not recommend it as you don’t know what you are growing. Maybe here there are different opinions or examples to share.

thanks a lot in advance for any suggestion, documentation, comment, safety alert you can share! :slight_smile:

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Hi Zoe,

This a pretty standard and straight forward activity, very popular in schools, public days, kindergardens… you name it.

Best to use some simple medium, like potato starch agar (or an old slice of wet toast)…
See some old workshop we did:

For growing it. best at kinda elevated room temperatures. 25-30° degree (yes it’s summer!), no incubator needed. also always safer to NOT grow stuff at body temp. 37°.

generally having the petri dishes or whatever containers you use, closed is a good idea, and you can cook / kill them in a steam cooker for disposal. as it’s kinda an optimal growth conditions for bacterias and molds, some people with immune deficiancies should not open and lick and inhale the dishes after it’s been growing for a few das. generally throw them away after 3-4 days. (same counts for that molded ove pizza slice you lefrt under the sofa!).

to make agar plates for putting whole phones we used some cheap containers (like tupperware) that had a more rectangular shape.

good luck!

Mbe a little sidenote…
such bacterial growth plates have NOTHING and absolutely NOTHING to do with viral infections or it’s spreading. nor do they say anything about pathogens…
all they say is that there are a lot of little buggers around on your had and your phone.
so do some tests on a normal phone and one that you just cleaned.

or check hand-washing…


Hi Marc,
thanks for feedback and tips.
Ok, the main message i get also from you is that it’s recommended not to grow stuff at body temp, because we don’t know what we are growing and we could be multiplying risky stuff especially for people with immune deficiencies.
And there’s not a protocol to do it in a safe way in a citizen science biolab even if the petri dishes are sealed.

I wanted also to try using to count colonies.
Have you tried it?


that’s not what i said… it’s totally safe enough. just throw them away after a couple of days.

Ok, do I misunderstand this sentence of yours:
“always safer to NOT grow stuff at body temp. 37°”

I interpreted that growing at room temperature is fine and safe to do workshops, but if you grow at 37° it’s not safe.

thanks for clarifying

Genau genau,
there is NO reason to grow stuff at 37°…
but again, on such potato medium you won’t grow bad too much stuff .
unlike if you grow stuff on human blood or other crap.

for this level of work the so called “GMLP” is good enough. wash hands, don’t eat in the work area, …etc.


Thanks for the link,
very useful.

“there is NO reason to grow stuff at 37°…”
It depends on what you want to explore. Our idea was to first start with simple exercises like with the phone and later, when more confident, explore the bacteria diversity in vaginal mucus and how it changes during the cycle or changing diet (more fermented food etc).

I’m trying to understand which level of safety measures different kinds of explorations need.


Of course i refer to your title to sample from the phone…

culturing human microbiota and assessing vaginal smears is a different example.

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