[compost_tea] Re: Grain sterilization

From: dkemnitz2000 <dkemnitz2000_at_yahoo.com>
Date: Thu, 06 Nov 2003 22:37:39 -0000

--- In compost_tea_at_yahoogroups.com, soilfoodweb_at_a... wrote:
> Any time you culture microorganisms in order to grow a specific
species, or set of organisms, sterilization has to be performed. The
set of microorganisms that are normal inhabitants of any surface have
to be killed if you want to be 100% successful at growing the desired
set of organisms.
>

Elaine you've talked against plating(enumerating) in a sterile medium
so long I sort of forgot about the possibilities of doing something
as you're mentioning above. I know the two processes are not "quite"
the same. I've worked in lots of food processing facilities the last
25 years (including Coors brewery)and just have not seen any cereal
grains sterilized for a culture growing medium. Of course we
sterilized Difco (in the LABORatory) and pasteurized milk in the
plant. We had "wild yeast" in the beer stream later ending up in the
bottles. Anyway thanks for the info. Dennis Kemnitz






> To be assured that a pure culture of Agaricus bisporus (the white
mushroom we all love to eat) will grow on a desired substrate, all
the other organisms on the substrate (food resource) have to be
killed, or a significant percentage of the time, some other organisms
will out-compete the Agaricus, adn the grower will lose money.
>
> Chris is absolutely correct about sterilizing grains. It's done
all the time.
>
> Typically grains used to make beer are at least pasteurized, and
usually sterilized, especially in large production facilities where
they can't allow contamination to destroy the product they are trying
to sell. Does the heat treatment affect the quality of the final
product? Sure it does.
>
> Wine production uses high sugar content, inoculation of HIGH levels
of yeast, and low pH to control the fermentation instead of
sterilizing the initial starting materials.
>
> If you use high heat on sugars and proteins - which is what grape
juice is all about - you denature the sugars and proteins, and the
yeasts you want for the fermentation won't grow. Some folks use
sulfur compounds to try to control yeast populations, but many of us
are sensitive to that sulfur in the wine.
>
> Why don't we sterilize or pasteurize the substrates gong into
compost tea brews? You could do that, except it is usually not
necessary. You do want to be careful though. We reacently had a
person sending in tea where tea had an unpleasant microbe growing in
it. The person got upset at me (they still aren't speaking to me),
because we showed them their tea was contaminated. We asked them to
send in all the starting materials for the tea, and proved that the
contamination was in the molasses. They wanted to sue the company
making the molasses (sigh), except they were using a molasses
container that they had been using for years. Probably that
container became contaminated by various people making tea. Not the
fault of the company providing the molasses.
>
> Take home story: If you put compost tea onto things you will eat
without washing them, make certain the material you put into the tea
are food-grade.
>
> Take home story number two: If you live in high human density
areas, wash your food before you eat it. What was on the hands of
the person who handled that food before you? Did that deer that
wandered through your garden pee as it walked through? Wash fruit
before you eat it.
>
> Haven't had time to go look for USDA peat pasteurization regs.
Will try to do that soon.
>
> Elaine Ingham
> President, Soil Foodweb Inc.
> SFI Corvallis, OR
> SFI Port Jefferson, NY
> SFI Lismore, NSW, Australia
> SFI Hilversum, The Netherlands
> SFI Cambridge, New Zealand
> www.soilfoodweb.com


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Received on Thu Nov 06 2003 - 19:14:08 EST

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