Injecting Through Polyfill: Sin?

hi all,

small question i’ve wondered about as i’m moving in to liquid cultures more than i have in the past:

assuming you aren’t using a fancier form of air filtration, is there any especial issue with using a a diy polyfill air exchange port for injecting/extracting liquid culture instead of a second devoted sealing port?

i mean, in terms of sterile practice, probably not ideal, but in a pinch i can’t imagine it’s significantly more risk of introducing contamination than just the regular standing risk of contamination from using a polyfill filter as long as you follow the same sterile needle practice you otherwise would.


I think the risk of dragging anything (spores, bacteria etc) that has landed on the top the poly fill in with the needle is there. It’s hard to really disinfect the top of it (like one could disinfect the top of an injection port).

But also if the needle has moisture, either from the inoculant or the receiving medium, then this could wet the poly fill on the way out. Wet poly fill could make problems later on with things growing in it.

Both of these are pretty minor in my mind. But that’s what I can imagine causing an issue.


agreed on risk of dragging in; think that might be mitigable a little bit with technique. polyfill comes out like a plume, i’d think entering through the side as much as you can, under the arch of the tuft might help. would imagine that spot is a bit more sheltered.

trying out, will see how it goes.