As a very recent arrival here, I am still reading the messages so if this
is redundant...I apologize. I can only comment on the Flavr-Savr Tomato,
though I recently heard of another tomato by another company that has a
much longer shelf-life.
All that was done with the flavr-savr was that an enzyme (which enzyme
escapes me at present) was effectively inactivated; this enzyme playing a
part in the ripening process so that knocking it out extends ripening.
The means of shutting it down was to introduce an anti-sense gene for the
enzyme into the plant (I don't know what promoter was used). Expression
of this gene produces, naturally, an "anti-mRNA" which base-pairs with
the normal enzyme's mRNA, thus preventing its translation. No nasty
additives. No threat to life, liberty, or the American Way at all. No
danger of Triffids spreading all over the world, killing us all. Very
simple, very nice...and the tomato taste one HELL of a lot better than
the normal store variety, more like that fresh-picked from someones own
garden, when ripe, and eaten right away with the benefit that it can sit
for a week or two on the shelf without getting disgusting. The other
tomato I just heard about has a reported shelf-life of up to a month.
Perhaps the company that made it extended the anti-sense procedure to a
whole cascade of enzymes(?).