> I am asking these questions because the organic standards
> prohibition on the use of GMO products may or may not
> include GMO cotton seed meal, GMO molasses,
> GMO yeasts, and so on, in field production.
Although I honestly believe the risk of from such things is vanishingly
small compared to naturally occuring risks such as mycotoxins or bacteria, I
understand the fears that people have, and respect the desire to know
whether GMO constructs are getting into their food.
> I believe we should define and determine whether or not,
> if GMO attributes are still found in the manure, if
> that manure, when carrying GMOs should be prohibited.
Here is an idea for a generic kind of test for traces of GMO's.
What you probably mean by "attributes" are fragments of engineered DNA. I
asssume you would agree that if these fragments are completely broken down,
they will pose no hazard (I don't think they are a hazard even if intact,
but you would probably agree that if broken down they are harmless). One
ubiquitous feature of these constructs is the presence of a relatively small
number of promoters. Promoters are like switches that keep expression of
the introduced gene turned on in a particular tissue or at a certain
developmental stage. A relatively small number of different promoters are
used for many different introduced genes. There may be other sequences that
could be used to generically detect engineered constructs, but I am not
enough of a gene jock to know.
Perhaps common sequences from promoters (or other parts of engineered
constructs) could be used as primers in a PCR assay. PCR (polymerase chain
reaction) is an exquisitely sensitive way of detecting pieces of DNA with a
known sequence. Traces of DNA in the sample, that are complementary
(homologous) with the primer are vastly multiplied in the procedure and
detected and identified on a gel, by spreading them out using an electric
field. This kind of assay could be used on agricultural products (meal,
compost, manure, oil, protein concentrate, molassas) to determine in a
fairly generic sense, whether relevant portions of engineered DNA were
getting through the process. It would be too expensive to do this routinely
on every batch of product, but a representative sample of batches could be
tested to show whether engineered DNA fragments of significant size can
survive the process in question.
> Or we may just end up blowing off the GMO contamination
> problem like we have aerial drift. I am not a big fan of
> testing.
I would recommend blowing it off because testing for such subtle stuff is
expensive. And, as Loren pointed out, there are lots of biological reasons
to think that "GMO attributes" are completely degraded by the soil,
composting, and many agricultural processes.
> I think the salient point is that no one knows......
I believe that some of these questions can be answered if the right
technology is brought to bear.
Dale
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