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During this lab exercise, you have an opportunity to see some places bacteria and fungi live. You may also be surprised to discover some places they don't live. Use your imagination when determining where to collect your sample. Do you think you will find more bacteria on your lip balm, the water fountain, the bathroom floor, the door handle, your pen, or the faucet? The answers may surprise you! Go investigate!
Experiment
Experiment
Materials:
2 - Tryptic Soy Agar (TSA) plates
1 - 0.9% saline or sterile water
2 - Sterile swabs
Protocol:
Dip your swab in your sterile saline or sterile water.
Press the moistened swab against the inside of the test tube to remove excess liquid.
Rub the moistened across your chosen surface.
Use the swab to streak your plate. Streak for confluent growth.
Note: Your instructor may also ask you to inoculate your plates by breathing on them, leaving them open to the air, touching them with your fingers, or by using another method.
In the next class, after the plates have incubated, you will look to see what kind of organisms have grown on your plate.
A swab of a cell phone grows a variety of cultures. What might yours look like?
A swab of the bottom of a shoe illustrates hearty growth of bacterial and fungal cultures. What do you think a swab of the floor would look like? What about your carpet at home?
This plate was exposed to the air coming from a hand dryer in a public restroom. Do you think paper towels would have more or fewer organismal colonies?
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