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Re: GM crops and mycotoxins, archive 2305



>Rick Roush wrote:
>>Given the recent debate on this server about GM crops in developing
>>countries, I thought the following was especially interesting, particularly
>>the points about GM crops diminishing mycotoxin food contamination and the
>>links of mycotoxin to esophageal cancer in many parts of South Africa,
>>followed by a report on the reduction of mycotoxins in Bt corn.
>
>The article said that GM crops "MAY also reduce post-harvest fungal
>infection".
>Are there published, peer reviewed papers that prove there IS a reduction
>or is this just speculation ?

>Robert
>Robert@tiamat.sonnet.co.uk

Robert:

I don't know, and in fact I have already written to try to get the author's address to ask the same question. The fact is there are reductions pre-harvest, as emphasised below.

Results of our studies have consistently demonstrated that hybrids
containing two of the Bt events (MON810 and BT11) experience
significantly less Fusarium ear rot and yield corn with lower
fumonisin concentrations than their non-Bt counterparts. Similar
results have been obtained in studies conducted in Illinois and
North Carolina (1, 2, 3). When conventional hybrids were subjected
to high populations of European corn borers, Fusarium ear rot
severity and fumonisin concentrations became elevated, often to
levels considered unsafe for swine and horses. Levels considered
safe for horses and swine are <5 ppm and <10 ppm, respectively.
Safe fumonisin levels for humans are unknown (4). Fusarium ear
rot and fumonisin levels in MON810, CBH351, and BT11 hybrids
were uniformly low (usually less than 10% of the concentrations in
the non-Bt hybrids) and were unaffected by European corn borer
populations.

Other studies also have shown reduced kernel infection by A.
flavus and lower aflatoxin concentrations in BT11 and MON810
hybrids compared with their non-Bt counterparts. However, these
reductions have been less dramatic than those seen for fumonisins
(5).

Sources

1. Dowd PF and Munkvold GP. 1999. Associations between insect
damage and fumonisin derived from field-based insect control
strategies. Proceedings of the. 40th Annual Corn Dry Milling
Conference, June 3-4, 1999. Peoria, IL.

2. LSI Health and Environmental Sciences Institute. 1999. An
evaluation of insect resistance management in Bt field corn: A
science-based framework for risk assessment and risk
management. Washington, DC: ILSI Press.

3. Munkvold GP, Hellmich RL, and Rice LG 1999. Comparison of
fumonisin concentrations in kernels of transgenic Bt maize hybrids
and non-transgenic hybrids. Plant Diseases 83:130-138.

4. Munkvold GP, and Desjardins AE. 1997. Fumonisins in maize:
Can we reduce their occurrence? Plant Diseases 81:556-565.

5. Windham GL, Williams WP, and Davis FM. 1999. Effects of the
southwestern corn borer on Aspergillus flavus kernel infection and
aflatoxin accumulation in maize hybrids. Plant Diseases
83:535-540.