For the past month, I have noticed what appear to be some type of crystalline or mineral precipitate on the outside of cell culture flasks. A 70% solution of ethanol completely removes it. It does not make sense that contamination would occur on the outside of the flask as there should be a lack of nutrients. The flasks are in a humidified atmosphere which has me wondering if there may be minerals in our DI water. Has anyone had this happen?
If flasks are always dealt with care and shelves are dry, there is no reason for minerals from water (even if you use regular tap water, as we do) for humidification, will end up drying on flasks in a humidified incubator.
It is possible that rather than minerals, you may have fungal contamination.
Years ago, I started buying only copper lined incubators. The water tray is also made from copper. Rather than using water bath, we switched to dry-baths and occasional fungal contaminations experienced by members of my lab stopped.
Have you checked your distilled water (ionic strenght and microbiological contamination?). What do you use as a preservative in your distilled water? What about your CO2 level and the possible formation of carbonates?
Hi Dr. Roques,
Thanks for answering. I will inquire with maintenance about testing the DI water for ionic strength. All microbes should be killed as all DI water is autoclaved before entering the incubator. Our CO2 level in all incubators is 5%.
If flasks are always dealt with care and shelves are dry, there is no reason for minerals from water (even if you use regular tap water, as we do) for humidification, will end up drying on flasks in a humidified incubator.
It is possible that rather than minerals, you may have fungal contamination.
Years ago, I started buying only copper lined incubators. The water tray is also made from copper. Rather than using water bath, we switched to dry-baths and occasional fungal contaminations experienced by members of my lab stopped.
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