Pouring Wort/Agar plates! Fail!!!

[passedpawn]

I like the looks of that Campingaz Bunsen.



Not that I think it will actually "clean the air," but I agree with working near a lit flame. More to create an upward air current that keeps anything from settling on the items that I'm trying to keep sterile, than to clean the air. Also, being hands free is a huge bonus to me. Flicking my Bic every time would get very tiresome.

I went with the spirit lamp, aka alcohol lamp, over the Bunsen type burner because the alcohol burns cleaner and a little cooler than propane.
I'm burning Everclear here.
I've read that methanol will have an invisible flame, ethanol will have a blue flame, and isopropyl will have a yellow flame.
I believe the orange/yellow tip of my flame is due to the burning of other gasses in the atmosphere along with the ethanol.
(Beer in photo for size reference)
View attachment 778539

There's an adage in biology that microbes do not fly. Can't remember who said this to me, but the point was that if you kept an updraft around your work, it would pull that microbes away. The microbes cannot direct their own movement, so they will follow the flow you provide, up and away.

 

[bracconiere]

There's an adage in biology that microbes do not fly. Can't remember who said this to me, but the point was that if you kept an updraft around your work, it would pull that microbes away. The microbes cannot direct their own movement, so they will follow the flow you provide, up and away.

what's the air get replaced with?

 

[passedpawn]

what's the air get replaced with?

air

I know what you're thinking - the newly drawn air contains the same microbes. Maybe. But maybe they don't settle.

 

[bracconiere]

air

as far as i know you either want 99.99% sterile air forcably blowing on it, or abslutly no draft at all? am i wrong?

 

[passedpawn]

as far as i know you either want 99.99% sterile air forcably blowing on it, or abslutly no draft at all? am i wrong?

I think the goal is no microbials landing in your work.

Perhaps a draft of air away from the work helps. It's possible it's all unnecessary. I don't really know. I suppose somebody has studied this. If you feel compelled, go find white papers and link. Thanks!

 

[bracconiere]

I think the goal is no microbials landing in your work.

interesting thought.

 

[Northern_Brewer]

Most folks in a lab pour their plates out on a bench top, not in a sterile environment. I certainly did.

Depends a lot on what you're growing - plates for antibiotic-resistant E. coli are one thing, but plates for yeast and especially slow-growing wildtype bugs from the environment are quite another, you need a much, much higher standard of cleanliness than with E. coli. It also depends on the lab - it may be less of an issue in an airconned, HEPA-filtered lab in a city but I had one in particular which just had doors and windows opening directly out onto a healthy ecosystem (in fact there was a colony of endangered bees in front of one window) and we had all sorts flying in - mayflies, ichneumon wasps, everything. So we always poured plates in flowhoods, except rarely antibiotic plates if there was no room in the hood.

For plating we'd generally work on the bench unless it was one of the exotic bugs, but always with a Bunsen - when I worked in government we had cute ones with IR sensors so you could turn them on/off without touching them. The convection taking contaminants up and away from your work is one consideration, but you need a flame anyway for sterilising your loop, flaming bottle tops etc. Normally I use a portable blowtorch for flaming.

I've not done it, but I've thought about using my cooker extraction hood as a "vertical" flow hood. Obviously not laminar, but it can give a good upward draft., and since my hob is gas it's got a ready-made "Bunsen" built in. I've got a granite cheeseboard to give a good, clean surface, it should work.

But in general the kitchen is a bad place for home microbiology, it has fruit and compost bins and spills of nutritious liquids - generally lots of things that can grow contaminants. As has been said above, you're better off in an office or spare room or somewhere similar.

 

[McMullan]

Airborne microscopic particles (transporting unwanted microbes) don't sink through warm air*. If the area is set up properly there's going to be a sterile envelop to work in around a Bunsen or similar. As sterile as air inside a laminar flow hood. In fact, the lids on freshly poured nutrient agar plates are fine left ajar until the agar sets with minimal condensation.

*Why sunlight is avoided in the work area. It has more than enough energy to make microscopic dust particles go airborne on a massive scale, just like that. Including as many mold spores as your plates can grow then some more. People who suffer with hay fever will know about pollen rising in the morning sun avoid this when streaking, too. Especially down the high street.