I made a blue cheese starter by putting a small piece of blue cheese on a piece of white bread. The white bread was then placed into a zip lock plastic bag and I blew air into it and just set in on top of my refrigerator. After about a week the bread was almost totally blue. In two weeks the bread actually crumbled into a blue dust.
The last time I made blue cheese I took a teaspoon of this blue dust and mixed it with water then strained it for any bread that might be left in the dust that I couldn’t see. I then poured the water over the curds and it worked perfectly.
At the beginning I was worried I might get other molds growing along side the blue mold but it didn’t happen.
The next time I do this I will photograph the procedure and post it.