Learning Sterilization Techniques

Learning Sterilization Techniques

Class: Tuesday, August 27, 2013

Today was our first day of microbiology lab! We learned proper sterile techniques in conducting ourselves, our lab stations, our lab equipment, as well as actual experiments.

Juliet wearing her lab coat and practicing proper sterile technique

It begins with the classy, new, starch white lab coats: to stop any microbes from coming in, we wear lab coats.  After the class is over, as we exit, we take off our coats to prevent any spread of microbes back into the environment we came from.

Before we did anything else, we pressed a unwashed finger onto an agar plate, then washed our hands, and pressed the same washed finger onto a different section of the plate. Then we placed the agar plates into the incubator at room temperature to grow the bacteria.






To prepare for the day's experiments, we then sterilized our lab station with 2% Lysol.

Sterilizing the inoculating loop

During this class, we learned how to properly sterilize an inoculating loop, using the blue flame of a bunsen burner.
The metal turns orange as it is heated.  This is necessary in order to kill any microbes to prevent contamination.

Removing the cap while holding the inoculating loop

We also learned the importance of heating the lip of the glass test tube, to prevent any contamination as well.  In order to do this, you must use one hand to hold the test tube, and the other hand holds the inoculating loop as well as the cap of the test tube.

Inserting the inoculating loop into the broth culture

Sterilizing inoculating loop

After each removal of the test tube cap or use of the loop, it must be heated and sterilized.


So why all this stress on heating and sterilizing? It is necessary to prevent contamination.  If contamination occurs, then the result of your experiment will be altered and inaccurate.

Pouring nutrient agar into plates

Next, we learned how to make nutrient agar to pour into plates, for bacterial culture growth. After weighing the correct about of nutrient agar powder (which comes from cows) we added it to boiling water.  It was then in high heat for fifteen minutes in the autoclave. After it finished, we poured the sterile agar into the plates, to be used for our next lab class.