rye grain unicorn bags and contamination.

[dallas_boy]

I've been using the same source of rye for about 2-3 years now. Up until about 6 months ago I've had nothing but contamination from this same rye.

The contaminants I'm getting are varried between blue/green, fuzzy black, tomentose ringed pattern like white growth. I'm guessing penicilium, black pin moulds, possible others?

Here are a few possible situations which I think have influenced this massive contamination outbreak.

1.) 1 year ago I let a friend borrow my pc to prepare some rye grain in jars, during sterilization the jars broke inside the pressure cooker and he did not clean the mess up, When I came to pick up the pc weeks later, I opened it up and there was abunch of moldly multi coloured contaminated rye grain cooked onto the pc which I then cleaned out. I'm considering this as a possible source of contamination - a contaminated pressure cooker...Is this possible?

2.) Another possible is my rye prep technique is not clean enough. I start by adding 3lbs dry rye into unicorn bags, add 1400ml of water and then let it presoak for 24hrs (for endospore germination) then I pc at 15psi+ for atleast 3 hours, usually 4 hrs. In the past when I had great success I would 24hr presoak, simmer, and then pc in jars.

3.) Or could I possibly have contaminated prints? I am currently testing this by doing a batch of rye and only inoculating 50% of the batch, and waiting to see if the uninoculated rye contaminates by itself..

4.) Maybe the rye vendor suddenly got a shipment of bad rye? This source is a large farm and feed supplier. and they sell it as "fall rye"

5.) The last but unlikely(in my mind) possible is that contaminants are passing through the tyvek filter, post sterilization. These are the original 8" x 20"? unicorn bags with filter. During sterilization the plastic tops are folded ontop of itself as to not let steam or water to have direct contact with filter? Can contaminants pass through tyvek?


Additional notes.

-I do not rinse/clean my rye, just add water and let presoak 24 hrs, then pc. Just as it says in TMC.

-I preseal the bags prior to sterilization and have no problem with them expanding and blowing out like some people have.

Once the rye has cooled I wipe it down with iso alcohol and stick the needle through the top of the bag and inoc straight down onto the rye, I then quickly cover the needle hole with tape( I can't see this tiny hole covered in tape being the issue, as I don't shake the bags after inoculating. All inoculation is via multispore.

-This outbreak of contamination started around the time that I got back the borrowed moldy pressure cooker, prior to that I used the same rye grain in quart jars and often had 100% success.

-After pc'ing bags for at least 3 hrs, I wait until the pressure has released and then take the bags/jars out of the pc to cool. This is the way I've done it forever.


It would be great to get some second opinions on this, as I have nobody I can personally I can discuss this with. Possibly somebody sees something that I may have overlooked?

Apologies for the long, boring post. I would add pictures if I hadn't recently lost my camera..