Science Buddies: "Ask an Expert"

Long story short, I'm doing a big research project and I need to measure the amount of airborne bacteria present in a hospital operating theater. I am putting petri dishes with nutrient agar in various locations in the operating theater. I am doing so with a number of different operating procedures. The amount of air contact with the petri dishes will range from 4 to 10 hours.

My question is, once I have grown the bacteria, statistically how would I determine the quantity of airborne bacteria in the operating theater based on the results from the petri dishes. Is there a method to extrapolating the amount of bacteria in the petri dish to the amount of bacteria in the air. And, would I have to account for factors such as growth rate of bacteria.

Also, if there is a more effective method to determining the amount of bacteria/microorganisms present in the air, could you please help me in that regard.

Thank you for your help,
Stefan Jovanovic

Hi,

Very interesting experiment. I don't know much about which route you should take for this experiment but
I found an article from Rapidmicrobiology that explains how to test for microorganisms in the air. One of the methods discussed is the Petri Dish method. Seems like it works and is the most inexpensive method.
http://www.rapidmicrobiology.com/test-m ... -samplers/

Hope this helps