How to avoid contamination in microbiology lab?How to increase efficiency and accuracy?

[niharika]

Please mention techniques, tips to avoid contamination while doing experiments and also suggest some tips to do work with maximum efficiency.Please provide links of important articles or videos related to this topic.Thanks in advance.

[supersapien]

The most important thing to understand, primarily, in a microbiology laboratory is to maintain absolute cleanliness. You should follow the following rules.

1. Never eat (or even bring) any food into the lab.
2. Always wear a lab coat (apron) and gloves.
3. Wear shoes....

See more in this PDF. http://www.as.ysu.edu/~crcooper/LabRules.pdf

[niharika]

plz mention how to pour medium into plates and inoculate without contamination.What all are the sources of contamination?why am I getting moisture in petriplates after autoclaving.

[CharonY]

Primary sources of contamination are your body and dust circulation in the lab. There are several methods to pour plates but first you need a clean area with little to no air circulation (e.g. avoid being in an area where people move or where air inlets are). Sterilize your hands, never move parts of your body (i.e. arms and face) over stuff that are supposed to be sterile. Work quickly but move accurately (takes some practice). The longer stuff is open, the higher the contamination risk.

Plan all your moves before execution. Usually you autoclave the medium with agar first, and then pour it into dishes. Stack the empty dishes and pour from bottom up (i.e. lift the cover of the lowest dish together with the other dishes on top, pour, replace, lift the next lid, etc.). In my hands this is the fastest way to pour while minimizing exposure.

Horiziontal clean benches are good, if you do not work with anything hazardous (as the flow keeps plates clean). Laminar flow hoods are also decent, although they are more designed to protect you. Still the overall airflow is controlled. Zero-flow boxes also work. Do not use the fume hood (unless you really got some nasty stuff in the medium).

Edited October 6, 2011 by CharonY

[StringJunky]

 

Here's some more

you can browse. Edited October 6, 2011 by StringJunky

[CharonY]

Hrrms, awfully slow. But OK if you only pour few dishes at a time.

[Papaver]

In a microbiological lab a burner is absolutely necessary. Whenever you have to work sterily you have to work nearby this burner. This includes also pouring agar plates. First you start the burner, then you open the bottle with the autoclaved agar medium, then you go with the bottleneck through the flame, then pour the agar. In between you can always repeat this to keep the bottleneck sterile.

 

Clean you pipettes and your bench regularly with 70 % ethanol. This is especially helpful when you do PCRs.

 

If you want to increase efficiency, make a plan of what you have to do. Think about how long your experiments take. Consider what has to be done first, what can you do later...

[CharonY]

Burners are a mixed issue, I did both and it really depends on handling. Advantage are of course the heat that kills microbes, but the disadvantage is convection. I found that flames are more useful if you have lengthy work (e.g. Hungate). For quick plate pouring I found it unnecessary with a little bit of practice.

Ethanol cleaning is a good idea, unfortunately it does not help terribly much against DNA contamination (e.g. for PCRs).

[Genecks]

I find that most problems in a microbiology lab are due to stupid people contaminating things.

I cannot understand why people cannot grasp the concept of contamination.

 

I think people are lazy, and lazy people think they can use shortcuts that are ok.

That may work in a chemistry class when yield is not so important.

 

But that does not work well in a microbiology class.

 

Most of the time, the way to prevent contamination is the use the burner to sterilize tools, ensuring that agar is not contaminated by flakes of hair, and using proper streak technique by preventing air contaminants from reaching the agar.

 

It's really easy to prevent contamination most of the time. People need to just think about contamination as they do things.

 

Now, if a person seriously is being preventive, there is a serious air issue.

As such, you probably want to put some agar plates out and see what falls on them, culture it, and maybe spray some Lysol around if there is a lot of germ growth.

 

Now if only I could sterilize the use of "plz" during serious discussions.

Edited October 25, 2011 by Genecks

[Greippi]

use the burner to sterilize tools

 

I hope you mean in conjunction with ethanol! It's the ethanol that does most of the sterilising.

 

Also, sounds obvious but make sure everything like pipette tips have been autoclaved/come from sterile packaging and are taken out in a sterile way. Any liquids that can't be sterilised by autoclaving can be made with as pure water as possible then filter sterilised.

Edited October 25, 2011 by Greippi

[CharonY]

It's really easy to prevent contamination most of the time. People need to just think about contamination as they do things.

 

 

It is fairly easy when working with fast growing bacteria, however if you need to incubate plates for weeks or months particles in the air (of which the experimentator is a significant source) are a big problem that cannot be circumvented by spraying disinfectants. But I agree, careful planning and placement of the experiments is extremely helpful.

 

 

 

 

I hope you mean in conjunction with ethanol! It's the ethanol that does most of the sterilising.

Depends on what you sterilize. Metals (such as inoculation loops can) can be directly heat sterilized directly (i.e. glow them). For glassware burning with ethanol is preferred (though the effect is heat sterilization and not chemical). Finally 70-80% ethanol can also be used for surface sterilization and then burned off. The two ethanol-based techniques have different uses.