What are the factors in determining the germination of spores to occur?

Question

isolation of spore-forming bacteria from dried food

Answer 1

Spores can wait up to 100 yrs. or more to germinate until under the ideal conditions.  It's simple to create those conditions, as they need nutrients, water, and the right temperature.  If you are trying to culture them, use Agar plate or broth, and if possible store them in a warm room or somewhere near human body temperature.  They'll be thrilled to germinate.  They've been waiting.....