GROWING GOURMET - Anto2ni.it

468 DESIGNING AND BUILDING A SPAWN LABORATORY
lab's integrity. After 3-4 weeks, Oyster mushrooms
will fruit within their containers, often
forcing a path through the closures. If unnoticed,
mushrooms will sporulate directly in the laboratory,
threatening all the other cultures.
The laboratory's health can be measured by
the collective vitality of hundreds of cultures,
the lack of diseases, and the diversity of strains.
Once filled to capacity with the mycelia of various
species, the lab can be viewed as one
thermodynamically active, biological engine.
The cultivator orchestrates the development of
all these individuals, striving to synchronize
development, en masse, to meet the needs of
the growing rooms.
Success in mushroom cultivation is tantamount
to not cultivating contaminants.
Confounding success is that you, the caretaker
cultivator, are resplendent with legions of mlcroflora.
Individuals vary substantially in their
microbial fall-out. Smokers, pet owners, and
even some persons are endemically more contaminated
than others. Once contamination is
released into the laboratory, spores soon find
suitable niches, from which a hundred-fold
more contaminants will spring forth at the earliest
opportunity. As this cycle starts, all means
must be enacted to prevent outright mayhem.
Contamination outbreaks resemble dominos
falling, and is soon overwhelming to all but the
most prepared. The only recourse is the mandatory
shutting down of the entire
laboratory—the removal of all incubating cultures,
and the necessary return to stock
cultures. After purging the lab of virtually everything,
a strong solution of bleach is used for
repetitive cleaning in short sequence. Three
days in row of repetitive cleaning is usually
sufficient. Clearly, prevention is a far better
policy than dealing with contaminants after the
fact.
No matter how well the laboratory is designed,
the cultivator and his/her helpers
ultimately hold the key to success or failure.
Each individual can differ substantially in
their potential threat to a clean room. Here's a
poignant example. At one time when contamination
was on an upward spiral, I had
eliminated all the vectors of contamination except
one: the MCU's, mobile contamination
units—which includes people and other mobile
organisms. Determined to track down the
source, I brought in an expensive airborne particulate
meter, used commonly by the
computer industry to judge the quality of
clean rooms. This unit measured airborne
contamination per cubic meter through a
range of particle sizes, from .10 microns to
>10 microns.
Several fascinating results were observed.
One obvious measurement was that, in a calm
air room, 100 times more particulates were
within one foot of the floor than were within a
foot of the ceiling. Truly, the air is an invisible
sea of contaminants. What was most surprising
was the contamination fall-out from each employee.
Standing each employee in the
airstream coming from the laminar flow bench,
I recorded downwind particle counts. The contamination
source was immediately identified:
an employee was generating nearly 20 times
the contamination fall-out than anyone else.
The dirty employee was summarily banned
from the laboratory. Soon thereafter, the integrity
of the laboratory was restored... The lesson
learned— that humans carry their own universe
of contaminants—and are the greatest
threat to clean room integrity.
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