Science Buddies: "Ask an Expert"

I am doing an experiment where I will test the effects natural herbs have on E.coli growth. I have made LB Agar plates where I plan to grow the E.coli, but I am not sure how I should grow the E.coli and what method I should use to introduce the herbs to test their effectiveness. How can I test the effectiveness of the herbs.

Hi,

The easiest way to grow bacteria for this type of experiment is to make a bacterial solution and then swab it onto your plates. Then, we usually determine antibacterial effectiveness using a "zone of inhibition" assay. We have very good instructions on this site for inoculating plates and doing this zone of inhibition with disks. I'll link to a couple of the articles here, but you should be able to find more with a quick search.

https://www.sciencebuddies.org/science- ... ml#summary
https://www.sciencebuddies.org/science- ... tion.shtml

In your case, you'll probably need to crush up the herbs you are interested in in a liquid of some sort and then soak your disks in that.

I hope this helps! Please post again if you have more questions.
JMP