How does e. coli bacteria colonies on agar cultures look like?

Question

well im doing a project and i would like to know what is the expected distribution of bacteria colonies using e.coli scrapped off the surface of raw meat and cultured in agar medium? (bearing in mind no coloring/dye and experiment is carried out in school labs, not scientific research labs)
Any links to images or drawings is greatly appreciated!

Answer 1

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The appearance of E. coli will vary depending on what type of agar you used. But I assume you have used a standard nutrient agar type of medium. In that case E. coli colonies will look like pale yellow, round, smooth colonies. Well, at least that is how laboratory strains of E. coli will look. If you are working with "wild" isolates, they might look a bit different.

This website has a picture of E. coli on a petri dish (scroll down a bit):
http://www.bioweb.uncc.edu/1110Lab/notes…

Here are some more:
http://parts.mit.edu/igem07/index.php/E.…
http://www.microbelibrary.org/microbelib…

And, in contrast, this is how E. coli will look on a MacConkey plate (pink plate).
http://www.microbelibrary.org/microbelib…

Good luck!