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Name: Kim
Status: Other
Age: 30s
Location: N/A
Country: N/A
Date: 2002


Question:
How do you make homemade agar?



Replies:
HI You should be able to make your own media at home. Make sure that you keep the petri dishes in their covering until just before you use them or they can become contaminated. You are right, the bouillon cubes won't "melt". You can get some Knox brand gelatin from the store and make it kind of like you would make jello for Finger Jell-O other words you want it a little stiffer than normal. Follow the directions on the package but add perhaps a little less water. Once you have boiled the water and added the gelatin, add some beef bouillon to it and dissolve it.

This give the nutrients that the bacteria need. Keep in mind, that this may not completely sterilize the media-there are bacteria that can survive boiling temperatures. Pour a little into a petri dish and let it solidify. This may take some trial and error to get it the consistency that you want. I am also thinking that if you are testing the effect of boiling the water you may want to add a little of your specimen directly to the agar before it solidifies.

Then any colonies which might be in the water specimen will be mixed directly in with the agar. You would then count the colonies after incubating. You can incubate them at room temperature for 48-72 hours. Since you are not completely sterilizing the agar itself you may be confused by any colonies that grow-do they come from the agar itself or from the boiled water? Unless you can autoclave your media, it will be difficult to completely sterilize your media.

vanhoeck



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