Ways of Disposal of Contaminated Cultures: The following procedures are generally used for disposal of contaminated culture:

• It is important to ensure that all contaminated material is disposed of correctly. Culture vessels should be removed from the culture area, unopened if possible, and autoclaved.
• Open items, such as Petri dishes with the lids in place, and pipettes or other items that have come in contact with a contaminated culture should be immersed in hypochlorite disinfectant (Petri dishes can be opened while submerged).
• If only one of a series of similar cultures is contaminated, it is necessary to discard the bottle of medium that was used with it, but if the contamination is widespread, then all medium as well as all other stock solutions and reagents, used with these cells, should be discarded into hypochlorite.

Eradication of Contamination: Eradication of Contamination in cell culture is a challenging job during safe culturing. There are different way for different organism, some example are given as follows:

Case-I: Bacteria, Fungi, and Yeasts: The most reliable method of eliminating a microbial contamination is to discard the culture and the medium and reagents used with it as treating a culture may be unsuccessful or lead to the development of an antibiotic-resistant microorganism. This procedure is optimal; however, the majority of cell lines do not form spheroids in this manner. Alternatively, aggregates may be formed from cell suspensions in stationary flasks, previously base-coated with agar. Aggregates may be left in the original flasks or transferred individually (by pipette) to multi well plates, where continued growth over weeks will yield spheroids of maximum size, about 1000 μm.

Decontamination should be attempted only in extreme situations, under quarantine, and with expert supervision. If unsuccessful, the culture and associated reagents should be autoclaved as soon as failure becomes obvious. The general rule remains that contaminated cultures are discarded and that decontamination is not attempted unless it is absolutely vital to retain the cell strain. In any event, complete decontamination is difficult to achieve, particularly with yeast, and attempts to do so may produce hardier, antibiotic-resistant strains.

Case-II: Eradication of Viral Contamination: There are no reliable methods for eliminating viruses from a culture at present; disposal or tolerances are the only options.

Cross Contamination: During the development of tissue culture, a number of cell strains have evolved with very short doubling times and high plating efficiencies. Although these properties make such cell lines valuable experimental material, they also make them potentially hazardous for cross-infecting other cell lines.

 

Interesting facts:

1. Once cell lines are infected, they may undergo spontaneous differentiation or altered function due to adaptation, which may have a profound impact on experimental results.