Question about growing bacteria?

[bbkevin817]

Hi, I'm doing a science fair project and it involves growing bacteria (E. coli) and determining the effectiveness of garlic in fighting bacteria. The link is here: http://www.all-science-fair-projects.com/project1098_39_2.html

 

I have a couple questions about this project...

1) How long would it take me to grow the E. coli without an incubator? I have an empty oven that (I think) maintains a constant temperature, and I have a heating pad; would I be able to use any of those as an "incubator?"

2) Why is it necessary to add the E. coli specimen to milk before putting it on the agar petri dish?

 

Also, this is irrelevant, but in case the topic above does not work out, I might do a project requiring ampicillin. If I end up doing that project, how will I acquire the ampicillin? Isn't a prescription from a doctor required for apicillin?

 

Thanks.

[Greippi]

E. coli like to grow at 37 celcius. I imagine using the heating pad will keep the petri dish at a decent enough temperature, ditto the oven if it's warm enough. Be careful not to get the temperature above that or you may well kill your bacteria. Usually I'd leave an agar plate of E.coli a day, if the temperature's lower than that then you may have to wait a couple of days. Do a trial run and see what happens. MAKE SURE THE PLATE DOESN'T GET OVERGROWN. Once you have a nice lawn of colonies it's ready to go.

 

Milk, I'll hazard a guess: E. coli needs something to "eat" so it's usually grown in a medium containing nutrients. If there are no nutrients on the agar plate (i.e. if it's just pure agar and no medium like LB), then I imagine the milk will provide some nutrients. But be careful of contamination - there may be other types of bacteria in the milk, or you might get mold growing or something!

 

Ampicillin: I'd ask a teacher to obtain it for you, there are companies that sell chemicals to science labs.

 

Another thing: have you considered honey? It has great antibiotic properties - I did an experiment on that in my first year of uni. Manuka honey from Australia is the most effective, but I found that local honey had some antibiotic properties as well!

Edited November 26, 2010 by Greippi

[John Cuthber]

If you are going to try honey you ought to try sugar as a control.

Anyway, are you sure that growing a potential human pathogen like e coli is a good idea for a science project?