Edible mushrooms---WICKED mold infection in tubs

Hi group,
Several years ago, I took up mushroom growing/mycology as a hobby.  I had good success with several edible mushrooms.  It was the straight forward method.  Spores on agar, agar to grain, then grain to grain.  Finally, spawning the colonized grain to bulk and fruiting.

Things were going pretty well.  An occasional infected jar, occasionally an infected tub, but no big deal.

Unfortunately, I've been battling mold for months.  The grain colonization seems to go fine, the agar dishes are good, everything seems fine.  The tubs colonize quickly, but then boom--mold.

I'm afraid this is what happened. Last fall I was cleaning up, and found a badly mold infected jar.  I opened it (in the basement), and could literally see a puff of mold spores go air born.  

I'm afraid I contaminated my house, everything has failed for months.

I had been using coir/vermiculite with some cow manure and a bit of coffee grounds.  Carefully given a good pasturization, careful attention to moisture content.  

When the contamination started, I went back to basics--straight coir/verm (no other additives).  Still, contamination.   I tried everything--growing in tubs, growing in shoe boxes, skipping the bulk substrate, an casing the grains directly....  Everything seems to result in mold. And right at the very last step of fruiting.

How do I trouble shoot this?  I'm a chemist by training.  I understand the importance of following accepted practices.  I'm pasturizing until an internal temp of 160F for an hour.  Good practices are being followed.  I just cannot get this to work anymore.  I had numerous successful grows, but I'm afraid this mold spore thing really messed me up!

Interesting problem. It's unusual to have late stage contamination. Mushrooms are pretty resistant once colonized. I suspect the vector is when you introduce fresh air to initiate pinning. Opening a contaminated jar near your grow area is poor practice. Contaminated jars should be PC'd before opening. At the very least open them underwater in a 10% bleach solution. You really don't want to breathe that stuff in. That said openning a spore laden jar should not be infecting your crop months later. Unless the spores found a hidden spot to grow and is actively growing and producing new spores. Look for areas where hidden mold may be growing.  Take a couple of sterilized agar plates and  open them in your grow area for a couple of minutes. Close them up and incubate them to see the amount and type of background contamination.

With a bit more information I might be able to provide more help. What are you using for a grow area? What are your running and fruiting tempertures? Exactly what type of mold(s) are you experiancing? What is the source of your fresh air? Is it filtered? A dirty filter could be a vector.

I feel your frustration but don't give up. You seem to be doing everything right.  Some patient detective work to find the source and eliminate it and you will be back in business.