How long should one incubate E. coli?

[a380bg]

I want to test the effects of UV light on the survival of E. coli. I am wondering how long I should incubate the dish with samples from the surface that was exposed to uv light.

[donnahardy2]

Hi,

Welcome to Science Buddies! Are you planning to do this excellent, but challenging project?

http://www.sciencebuddies.org/science-f ... p017.shtml

E. coli should be able to grow with overnight incubation at 37 degrees Centigrade or within two days at ambient temperature. UV light will damage the cells, so it may take a few hours for the bacteria to recover and start growing again, so if there are no colonies after 24 hours, incubate the plates another day or two to verify the results. Be sure and use a positive control that is not exposed to UV light in case you have killed all of the bacteria, and a negative control, if possible to verify your agar plates are sterile.

Please post again if you have any questions.


Donna Hardy

[a380bg]

Thanks for the quick response! I was asking for a friend in my class.