Expert: Walter Hintz - 10/26/2005

Question
My science fair project is to grow bacteria and fungi in a petri dish and seee how different things affect the growth.  So I was just wondering if you knew of any recipies for a medium that is sort of like a gelatin mix with ground beef or beef bulion. my science teacher said that that this is what i need to grow it in if I want any credit at all.  Thanks a bunch.
                  Sincerly,
               Colton  

Answer
Hi Colton:
 The best medium for growing bacteria for projects is nutrient agar which is indeed a beef medium.  It is easy to make.  Get some plain gelatin like Knox gelatin.  Follow the directions on how much water to use but be sure to boil the water and put about one beef boullion cup per cup of water.  Be sure to use sterile petri dishes and keep them covered as the agar sets.
   Before you go to all this trouble you might want to find some prepared media first. If you have a college near you check with the biology department there to see if they will give you some media plates or check with your local hospital.
 If you need any help with your experimental design let me know.  I was a bacteriologist while in the Army.