GROWING GOURMET - Anto2ni.it

spawn is gravity fed or hand broadcasted onto
the straw as it is being ferried away. Foot activated
switches are helpful in controlling the
off-loading of the substrate from the Phase II
box with the conveyor.
When spawn is placed directly upon the surface
of pasteurized straw, mixing is strongly
advised. Cement and soil mixers, specially
adapted funnels, ribbon blenders, and
"Archimedes screws" suffice. If the spawn is
laid upon straw and not mixed through, growth
layers form resulting in uneven colonization.
The advantage of removing the straw and inoculating
by hand is that the process can be
interrupted and recurrent cleaning can occur.
By intermittently disinfecting, cross-contamination
can be prevented. With automated,
continuous ioop systems, the likelihood that
contamination can travel throughout the facility
unchecked is greater. Special attention to
detailed disinfection is necessary with these
systems to prevent disastrous results should
pasteurization be incomplete. Once spawn has
been sown throughout the straw, the inoculated
substrate is placed directly into the "fruiting"
containers, usually columns, trays, or bags.
Each container must be vented so the myce-
Hum can respire as it colonizes the substrate.
Alternative Methods for
Rendering Straw & other
Bulk Substrates for
MushroOm Cultivation
Several inexpensive, alternative methods
can be used for treating straw (and other bulk
materials) that do not involve heat treatment.
The first three are chemical; the last is biological.
Surely other alternative methods will be
developed as imaginative entrepreneurs experiment.
By sequencing a substrate through a
CULTIVATING GOURMET MUSHROOMS 189
combination of biological and chemical treatments,
heat pasteurization can be entirely
avoided. Small pilot-scale experimentation is
strongly encouraged before cultivators attempt
these techniques commercially. The future use
of such methods is promising.
The Hydrated Lime Bath Method
Hydrated lime (calcium hydroxide) is extremely
alkaline and water soluble. By
immersing straw into water baths high in hydrated
lime, competitor fungi and bacteria are
largely rendered inactive from the drastic
change in pH. The preparation is quite simple.
Two to four lbs. of lime is added for every 50
gallons of water. (Since a gallon of water
weighs 8.3 lbs. this ratio is equivalent to 2-4
lbs. lime /415 lbs.water or about .5-1.0%) The
pH of the water skyrockets to 9.5 or higher.
Once dissolved, chopped straw is immersed
into this highly alkaline bath. Under these
caustic conditions, pH-sensitive microorganisms
soon die. Subsequent to an overnight
soaking, the water is drained and discarded.
(Note that this highly alkaline water kills many
plants and should be prevented from entering
any sensitive ecosystem or watershed.) The
straw is then drained and inoculated using standard
methods. It is not unusual for the straw to
achieve a pH of 8.5 or higher after soaking.
Oyster mushroom mycelia can tolerate this alkaline
environment better than most
competitors. After three or four days of initial
growth, pH slowly falls as the mycelium races
through the straw, secreting acids and enzymes.
One week after inoculation the straw
should be fully colonized. If colonization is not
complete within 7-10 days, competitors usually
arise. Optimizing the parameters for the
species being cultivated greatly influences the
success or failure of this simple method. Please
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