Microbe

Hi! I'm considering growing bacteria in agar in petri dishes. However, I have heard that once bacteria have grown in the agar, you should not open the dish for safety reasons. I would like to ask: What are the risks? What should I and shouldn’t I do to avoid growing harmful bacteria? And if it is best not to reopen the dish, then what is the point of using them, if you cannot apply the microbes to a slide to be analyzed under a microscope?

Thanks again for the responses guys! I don’t intend to do any intensive research, just basic colonies. I probably will use half of the pack, making about half a liter of solution, and go with the mason jar technique.

Thanks for the response! What about storing the extra agar in a sterilized mason jar?

Hi. I have a question about agar used for growing bacteria. The package on my agar powder says to use the entire pack for 1 liter of solution, which will fill about 50 petri dishes. But I however only wish to use a couple of petri dishes at a time. Should I use the entire pack and simply store what's leftover, or measure out what I need?