Quarantine helps avoid the spread of contamination
Tissue materials and cells which have been transferred between laboratories must be considered a potential source of contamination until the absence of microorganisms has been documented by validated methods, or until authentication of the cell line has been performed. Ideally, such materials should be kept in a separate room that is equipped with its own biosafety cabinet and CO₂ incubator. Only after biological materials have tested negative for contamination and cell lines have been authenticated will they be transferred to the general cell culture laboratory.
In general, primary cells or tissue cultures always bear the risk of endogenous contamination. Therefore they should be separated from continuous cell lines. Again, the ideal solution would be a separate cell culture room. If this is not possible, a separate designated quarantine CO₂ incubator and biosafety cabinet will help reduce the risk of spreading contamination. If the option of a separate room or separate equipment is not given, it is recommended to confine suspect cells to a separate shelf in the incubator and use them last, at the end of the day, after all "clean" cultures have been maintained and all experimental work has been completed.