I have read some vague descriptions about how to screen the CO2 incubator as the source of contamination. I saw recommendations to leave a plate of cell culture media in the incubator and view it under the microscope after a day (or so). What are your procedures for screening the incubator? Would you recommend leaving the plate opened or unopened? Thanks!
First of all, your plate has to be closed. Incubators are not sterile areas, they must be as clean as possible, but they are not sterile. If you leave the plate open it will most certainly get contaminated. It is hard to check if the incubator is the source. First check the water tray, look closely and if you see that after few days (7 for example) of renewing with sterile distilled water you see growth, that possibly means you have a contamination problem (probably fungus). Another sign is that when growing cells in multiwell, the wells of the corners tends to contaminate. In some brands they have more contact with the air and if there are many spores floating are the first to contaminate.
I would advise you to do a deep cleaning of the incubator, it is always useful. If general and frequent contaminations keeps happening keep in mind that may be other sources of contamination such as flaws at the laminar flow, the CO2 of the incubator or even the pipete filler. There are protocols for decontaminating the incubator with formalin but I have never tried those.
Hope it helps!
Diego
A covered plate should not get contaminated just by sitting in an incubator, even if that incubator is filthy. Incubators are not meant to be sterile. However, a clean incubator is always desirable (decontaminated surfaces and clean water).
As others mentionned, the contamination you are experiencing comes from somewhere else (biological hood, pipetting, culture media). I'd start by testing the culture media. Simply pour some of it in a sterile culture flask and leave it (closed) in the incubator for a week. If you have growth, then discard the media bottle you were using.
- Badges
- Science topic