Mushrooms: Grain Spawn Inoculations

Picking up where we left off on the mushroom growing posts; this post will give a quick glimpse into how we inoculate our grain spawn masters from petri dishes, and our grain spawn bags using what is called grain-to-grain transfers.  All of this work must be done in a sterile lab, or in a semi-sterile environment such as a glove or still-air box. Our operation uses sterile lab technique so that is what we will highlight.  This all can be done with low-tech methods but success is variable.  When growing mushrooms for sale to restaurants or store fronts they need a consistent (usually weekly) supply.  Meaning that consistency is paramount to running a successful mushroom op.  This is one reason why we use sterile lab technique. All of the pictures (below in the slideshow) are taken within our lab.  We are currently in the process of a make-over for our laboratory.  The next posts you read/pictures you see after this one will all be of a new, upgraded setup. This will be our fourth lab setup we have used over that last 4 years of growing mushrooms.  We had to start small and cheap, then slowly expand as the operation grew.

So all of the bags and jars of grain have been prepped, sterilized and emptied into the lab (this was all detailed in the previous post called Mushrooms: Grain Spawn Prep.)  Before we enter the lab we shower, put on clean clothes, pull our hair back, then put on the lab suit and surgical face mask.  Once inside the lab, we wipe down all surfaces with %70 isopropyl alcohol.  Then the bacticinerator is plugged in (sterilizes the scalpel blade between uses, without a flame) and the petri dishes, jars, and bags are put in the que to be inoculated.  It is always good to know what your inoculating beforehand; write what needs to be done as a list and bring this with you into the lab.  This way no time is wasted figuring out what needs to be transferred where, and all the time can be devoted to sterile technique.  I will explain agar perti dish to grain master jar transfers first.  Place the desired culture within the perti dish in front of the laminar flow hood as well as the jar to be inoculated.  Place the scalpel into the bacticinerator for sterilization (or use a flame.)  While this is happening loosen the lid all the way on the jar and remove the parafilm wrapping around the perti dish. Once the scalpel is red hot, the lid of the petri dish is removed.  Then cut a bunch of squares out in the petri dish (pictured below in the slideshow.)  Use the scalpel blade to "stab" the wedges from the petri dish.  Open the jar lid and thrust the scalpel downward into the jar.  The wedges will slide off the blade and into the jar.  Put the jar lid back on and tighten.  Don't forget to label the jar with the type of mushroom and the date it was inoculated.  Then shake the jar to distribute the wedges throughout the grain.  Let it sit at room temperature within the lab.  After 5-7days shake the jars again and let them colonize for some more time. They will be fully colonized and ready for use in about 10-14 days after inoculation.

 Now for inoculating grain spawn bags using the grain-to-grain transfer technique.  Before starting, clean off the surface and the bag heat sealer with isopropyl alcohol.   Take one of the jars that is fully colonized (one that was made 10-14 days earlier) and shake it up to break apart the grains.  As the mushroom mycelium grows it will eventually turn all the grains into one solid mass.  Put both the bag and the jar in front of the laminar flow hood, then loosen the jar lid.  Carefully open the grain bag in front of the flow hood, making sure the bag opening never leaves the area in front of the hood (or contamination is likely.)  Remove the lid from the jar and pour a portion of its contents into the grain spawn bag.  Set the jar back down and cover it quickly with its lid.  Then bring the grain spawn bag up to the sealer, and heat seal it.  Once sealed shake it to distribute the grain from the jar throughout.  Label the bag and set on an open wire shelf within the lab.  The grain bags do not need to be shaken again, as the jars do.  The bags will be fully colonized in 5-10 days.  This is how a grain-to-grain transfer is made.  The bags would be labeled G2, meaning second generation of spawn.  Generally, one can go up to 3 generations, but any more and efficiency is decreased.   Either the jars or the bags can also be used to inoculate the end substrate (sawdust or straw) for the production of mushrooms.

There you have it, the next step in the process of growing gourmet/medicinal mushrooms:
Production of grain spawn masters and grain spawn bags.

Thanks for stopping by, and don't forget to say hallelujah every once in a while:

 We really do live on a beautiful planet.