Re: Milling GMO (was HACCP)

Loren Muldowney (loscott@envsci.rutgers.EDU)
Fri, 12 Nov 1999 12:21:21 -0800

Wilson, Dale wrote:
> With discrete seeds or grains,
> sensitivity is limited by the number of kernels taken to be ground in the
> sample. If you grind together 10,000 grains, then the sensitivity is on the
> order of 1 in 10,000, or 0.01%. But when grain is sampled AFTER milling,
> the sensitivity may be excessive (that is, in terms of percent GMO grain
> needed to produce a positive reaction).

Dale, are you telling us that the % sensitivity of the PCR changes from
whole grain to flour?

> It would not be surprising to mill
> grain that tested negative, then find that the flour tests positive, due to
> the presence of a minute percentage of GMO kernels in the bulk.

Is this due to the distribution of dna fragments between the various
parts of the grain, with relatively more in the flour than in the whole
seed? I'm having trouble imaging why the sensitivity would be affected
otherwise. Thanks for any insight.

Loren

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