You will be met with nothing but sorrow until you get some sort of sterile procedure in place. Yes, there are many organisms that would overwhelm the mushrooms

You will be met with nothing but sorrow until you get some sort of sterile procedure in place. Yes, there are many organisms that would overwhelm the mushrooms you "want". There are mushroom spores covering every inch of earth. Mushrooms have a very specific lifecycle and your job as the mushroom grower is to make those chance occurrences a regular thing. The good news is its really pretty easy to do on a small scale.