Re: NOSB minutes on Compost Tea

From: Elaine Ingham (Soilfoodweb@AOL.COM)
Date: Sun Nov 10 2002 - 09:11:10 EST


Let's clarify the different kinds of compost tea that you might be concerned
with, and ones that you don't need to be concerned with. If I forget a
category, or you see the need to split a category, please chime in -

First, if you apply tea made from any source more than 90 to 120 days before
the crop surface would be consumed, there are no worries.

Second, compost tea made from plant-based, no human waste compost. E. coli
is not present in the starting materials, not present in the compost. This
category should be of no concern to folks with respect to the human pathogen
question.

Third, compost tea made with food waste material that could have low levels
of E. coli. E. coli is fairly easily reduced to non-detectable levels with
this type of compost. Testing might be necessary to document that E. coli is
not present in the final compost material, and that it is then safe to apply
to food plants.

Fourth, manure-based tea is what the E. coli concern is all about. We can
make compost tea from manure-based compost without any E. coli in the final
tea. BUT people also manage to make compost tea from manure-based compost
that contains E. coli.

The problem becomes, how do you KNOW that you managed to exit the E. coli
from the tea? What are the parameters that allow E.coli (and other human
pathogens) to be destroyed? We have done it, but now we need to understand
what the important factors are in producing these teas routinely.

So, that's where the situation is. Don't go ballistic about compost tea in
general. But on plants that you eat without washing the surface of the
material you are going to consume, stay away from compost tea made with
manure-based compost.

Elaine Ingham
President, Soil Foodweb Inc.
www.soilfoodweb.com


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