GM Sweet Corn Investigation CompletedThursday, Aug 7, 2003
The Ministry of Agriculture and Forestry today announced that it had completed its investigations into a sweet corn crop grown at Gisborne earlier this year which was reported to contain some GM material unapproved for growing in New Zealand.
The investigations were prompted by a New Zealand company alerting MAF of test results conducted in Japan by a food service company that had conducted routine testing of a proprietary topping mix. This mix contained sweet corn sourced from New Zealand.
Testing completed at the AgriQuality GMO Services facility at Melbourne identified the presence of a GM variety called Bt11 in product samples but at very low levels - less than 0.1% or less than one seed in 1,000. Corn product from three of the four fields investigated returned positive tests for Bt11. Bt11 is a type of GM maize and sweet corn that has been modified to be insect resistant and herbicide tolerant. Food Standards Australia New Zealand has assessed this variety of corn as safe for human consumption, although it is not currently grown or sold in New Zealand.
MAF's investigations as to the likely source of the GM material involved analysis of seed lines planted in the four Gisborne fields in question; examination of all sweet corn and maize crops grown within 300m of these fields; and a review of the harvesting and processing systems used by the company.
MAF's analysis of products taken from surrounding sweet corn crops that flowered at the same time as the crops in question has also produced negative test results for the presence of GM. Similarly the review of the company satisfied MAF's review team that it was highly unlikely that the presence of the GM variety resulted from mixing during harvest or processing of this crop. Testing by MAF and the seed producer on the seed line grown on all the four fields was negative but the only known link between the fields is the seed sown and therefore the possibility remains that the imported seed was the source of the GM material.
A second variety of sweet corn was planted on one of the four fields in question. Because of this, MAF secured seed from the same line from the company and arranged for this to be tested. A positive test was obtained from this seed, but the concentration is so small (less than 0.05% or less than five seeds in 10,000) that the actual GM involved can not be identified.
MAF placed compliance orders on the four fields under investigation. MAF and ERMA have reviewed post-harvest management that was applied to these fields and concluded that they are low risk. The compliance orders have now been cancelled and the four fields approved for normal use. MAF's investigations have extended to determining the extent of other plantings of the same two imported sweet corn varieties in New Zealand last spring. These plantings comprised 98 fields or 775ha. Some of these fields have, subsequent to harvesting of the grain, have either been grazed or have been planted in winter grasses.
Advice provided to MAF by specialist agronomists on all plantings of these seeds indicates that there is an extremely low risk of residual seed germinating to produce viable sweet corn plants, due to the crop being harvested when the kernels were immature and the post-harvest management systems involved. MAF is working with industry to identify all the fields that were planted from affected lines and is working with ERMA to ensure that these fields are managed appropriately.
As a precautionary measure, MAF has seized for destruction all remaining seed from the original imported lines to ensure none can be planted.
In the light of these events MAF officials are now reviewing testing procedures used for imported sweet corn and maize seeds. The protocol is already very stringent and few changes are envisaged. Nonetheless, options will be discussed with other government agencies and stakeholders.
A copy of the ministerial briefing document is available on MAF's web site, together with other more specific details of the seed testing and field appraisals.