Twenty simple ways to prevent culture contamination

Even if the problem cannot be fully eradicated but it can be prevented with some protective measures. The first step is to correctly recognize the type of contaminant and the way by which they are getting introduced into the culture is the first step for preventing culture contamination. The key to prevent contamination is remaining aware, that will save us and our lab from headaches. Let’s us discuss on some of the common ways for preventing culture contamination.

1. We should always keep our lab clean by utilizing disinfectant, which will prevent formation of bacterial spores. The work surfaces should be kept clean and more attention should be given to frequently used equipment like laminar airflow, water baths, incubators. One of the major sources of microbial contamination, which we often overlook are areas like the cooling coils of defreeze or a refrigerator. Therefore, we should pay attention to such areas.
2. We should always use good aseptic technique. While working in lab we should wear proper protective equipment like lab coats, gloves, etc. We should always wash our hands before entering and leaving the lab.
3. We should perform all sterile transfers inside biosafety cabinet or other proper enclosure, and that should be cleaned properly on frequent basis. This will give protection to both the workers and the samples, and prevent the contaminants from entering.
4. Labelling of the cultures and other supplies and solutions should be done carefully for preventing any kind of accident.
5. Cross contamination which is major type of contamination should be avoided by bringing the cell lines from well known cell banks and by checking the cell lines characteristics frequently.
6. Isotype analysis and DNA fingerprinting can also be performed for knowing about the presence or absence of cross contamination.
7. We should monitor all our supplies, solutions, media and the existing cell cultures before utilizing them in our work. The routine supervision should be simple for ensuring that we use it but should be thorough for catching any hint of contaminants.
8. If the culture has become contaminated, then autoclaving it can save from eliminating the infection. In case, if the sample is irreplaceable, then certain chemicals and antibiotics can save the sample for contamination.
9. We should not install CO₂ incubators just under the HVAC units, as it may cause the contaminants to blow into the chamber.
10. We should avoid using some routine antibiotics which will ensure that the resistant microbial strains are not chosen and the main contaminant is left.
11. On a monthly basis, we should do mycoplasma testing, so that they will not remain hidden among the cells.
12. We should always clean the inner part of the biological safety cabinets (BSC) frequently with 70% ethanol and on monthly basis cleaning should be done everywhere like under the working surface tray also.
13. Before conducting any experiments that involves BSC, we should plan in such way that there will be minimal use of hands in between. Like we should load everything before conducting experiment and we should remove waste after only finishing.
14. We should keep all the equipment inside the lab.
15. Despite all the protection we have taken there is still possibility of contamination as there are abundant of microorganisms present in environment. Therefore, to ensure extra prevention it is better we should do regular filtering of all culture media, so that all unwanted particles should be cleared that have accumulated. We can use membrane filters for this.
16. We should perform inspection of all laboratory places and equipment for any kind of contamination presence. This we should try to do at least once in a week.
17. We should always keep the bottle, tubes or plates closed.
18. After finishing work, we should follow some cleaning procedures on regular basis like disposing materials in proper way, wiping working surface with ethanol and keeping the UV lamp of the laminar airflow for about 10 minutes for sterilizing the working area.
19. While carrying unsealed cultures we should be more careful and we should carry it either trays or boxes, so that contact with air is prevented.
20. We should always try to keep the packed sterile solutions like L-glutamine, trypsin and antibiotics in small volumes so that number of times we use it is decreased and thereby decreasing the chance of contamination.

Executing these steps can help in enhancing the reliability and quality of research, thereby decreasing the time loss and keeping the waste and cost to minimum. Adhering to this practices will help in maintaining the feasibility and reproducibility of the culture.