Step 7: Inoculation
Inoculation is the process of introducing spores of your chosing into the sterilized substrate to take hold and grow.
In this step, be sure to take precautions to prevent contamination of the jars!!
Leave the jars in the pressure cooker until you are ready to Inoculate.
It is best to use a cleaned small room (such as a bathroom), HEPA flow hood or glove box when Inoculating.
Here is the basic order of things during the Inoculation procedure:
1. Open the pressure cooker
2. Remove a jar
3. Heat the syringe needle until it is red hot, with either a lighter or alcohol lamp
4. Remove the foil
5. Insert the needle into the hole you punched with a nail earlier
6. Inject some (about 1ml or so) of the spore saturated fluid into the substrate, on the wall of the glass jar. You should be able to see the needle tip and the water run down the side of the jar.
7. Repeat with the other nail holes
8. Replace the foil and continue with the next jar, reheat the needle if it touches anything unsterilized or every 3 or so jars to prevent contaminations.
See the second picture on this step for an example of contamination, green penicillium mold is a common contaminant. Yellow and pink discoloration is another sign of contamination.