Minimum Amount Time to Incubate E.coli

[deleted-942861]

Hello,
I'm using e. coli in one of my science fair projects but I'm only able to work on the project once a week for 2-3 hours. I know you should incubate e. coli overnight but is it possible to only do it for 2-3 hours before putting it in the fridge? or is there a way to incubate it for a week without killing everything off or having too much of it grow (i need to be able to count the colonies)?

Thank you

[carolynml]

Hi soapymg,

E. coli will likely overgrow if left in culture at 37 degrees C, the typical temperature at which it’s incubated, for a week. I would suggest starting your culture and letting the bacteria grow 24-48 hours (however long it takes to yield countable colonies). Once the bacteria has sufficiently grown, the plates can be moved to a 4 degree incubator, where they can be stored for several weeks. This will prevent them from overgrowing, and you can count colonies whenever you have a free window of time. Good luck with your project!