and what about new crops?

[Rick Roush <rick.roush@adelaide.edu.au>]

Where is the safety testing on these foods?

Rick


From: Dave Wood
Subject: Natural Plant toxins

Spina bifida in the newborn is given as `a possible consequence of
ingesting too much solanine' by mothers eating traditional Solanum
vegetables (Schippers, R.R. 2000 African Indigenous Vegetables: an
Overview of the Cultivated Species. Natural Resources Institute,
University of Greenwich, p. 175.). There are many Solanum species (with
solanine and other nasty alkaloids) used throughout Africa for their
edible leaves and fruits. They are tricky to identify and to prepare.
Other symptoms include vomiting, diarrhoea, and delirium leading to coma
and death. When symptoms are recognized in time, people switch to other
vegetables to detoxify themselves.

I don't have the sorghum reference to hand - I'll try to get it, but it
was in the nature of folk wisdom in a sorghum programme I once worked
with. Sorghum is a major target for birds (Quelea) in drier areas of
Africa. Birds don't like eating the red, bitter soghum (probably tannin)
but this can't be used as a deterent as it causes digestive problems in
humans, and eventually cancer (although I think it can be used for beer).
The sorghum people at Texas A & M may know. And doesn't chillie pepper
cause gastric cancer?

There are dozens of traditional crops that are toxic unless treated, or if
taken in quantity. For example, toxicity is a major feature of crops
originating in S. America - including potatoes, Lima beans, common bean,
quinoa and bitter cassava. Problems start when they are moved away from
their traditional areas, and the indigenous processing knowledge is lost
in transit. In CIAT we were putting a heat-labile insect toxin in common
bean from a wild relative to protect against bruchids, by conventional
breeding, when somebody pointed out that African kids liked to eat raw
beans (chick pea and faba bean) which is never done in Latin America as
raw beans are dangerous: Africans would have killed themselves eating the
CIAT bean raw, so the programme was stopped. One classic is the akee
(Blighia sapida - a fruit tree named after Captain Bligh of the Bounty and
a big delicacy in the Caribbean). Unless really ripe it is a killer (for
example, it killed Wilson Popenoe's wife in Honduras, and he was a skilled
botanist). You mention lathyrism from the vetch-pea in India: many other
pulses are sub-toxic.

A major reference is D'Mellor et al. (1991) Toxic Substances in Crop
Plants. Royal Society of Chemistry, London: the title alone says it all.
Norman Simmonds in his Principles of Crop Improvement (1st Edn.) p. 15
notes the loss of toxicity during domestication in lots of species,
especially roots and tubers (but there is still a lot left and potato and
bean breeders check before releasing varieties). Most of these anti-GM
activists are supermarket shoppers, with no idea of what food is like in
the real world.

It seems that a lot of the aversion to GM crops is intellectually the same
as the aversion to inorganic fertilizers at the time of the founding of
the Soil Association in the late thirties (there's an account of this in
the Agricultural History Review sometime in 1999). This was politely
called neovitalism (and less politely, `muck and magic') - the belief that
there was a vital principle in plants which came from the `natural' soil,
and which promoted plant health, and in turn, human health. It couldn't be
proved, but that didn't matter. Now we have the argument that GM crops are
unhealthy - can't be proved, but so what! The parallels are close.

One factor that has not been considered by the `zero tolerance' demands
for GM free crops in Europe is `contaminated' pollen blowing over from
North America. There must be billions of grains of GM maize pollen
crossing the Atlantic weekly (but it may lose viability before it lands on
this side). So much for quarantine and separation distances.

My regards,

Dave