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Adventitious presence of GMOs: Scientific overview for Canadian grains
T. Demeke, D. J. Perry, and W. R. Scowcroft
Canadian Journal of Plant Science 86: 1-23

Canadian Grain Commission, Grain Research Laboratory 1404 - 303 Main Street, Winnipeg, Manitoba, Canada R3C 3G8

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ABSTRACT

The global expansion in the development and cultivation of genetically modified (GM) crops has increased international concern about adventitious presence of GM materials in non-GM seeds and grains. GM events in canola, corn, soybean, cotton, flax, papaya, potato, squash, sugar beet, and tomato have received regulatory approval in Canada. However, GM cultivars are only in commercial production for canola, corn and soybean. More than 30 GM events have been approved in these three crops. Cases of unapproved adventitious presence of GM materials that have impacted grain trading and handling in Canada and other countries include StarLink^TM corn, GT200 canola, GM canola in mustard and recently Bt10 corn. Some countries have established tolerance and traceability requirements for adventitious presence of GMOs, while others are in the process of developing or adopting legislation. The threshold for labeling of adventitious presence of approved GM material in non-GM grain varies from 0.9% (e.g., EU) to 5% (e.g., Japan). Progress has been made in the development of DNA- and proteinbased GMO detection methods. However, only a limited number of these detection methods have been internationally validated. The challenges for detection methods include sampling, a lack of certified reference material, a lack of DNA sequence information for the design of event-specific primers, and the sheer number of individual events that may be present and tested for. Current efforts by ISO and CEN will be valuable for establishing harmonized and standardized GMO detection methods.

Lack of agreement on tolerance and traceability of GMOs threatens global trade

At present, genetically modified (GM) crops are cultivated in 21 countries, and it is estimated that initiatives to develop novel biotech crops are underway in at least 63 countries, with increasing involvement of developing countries. Adventitious presence (AP) of GM materials in non-GM crops is considered an inevitable consequence of the production of biotech grains, and may be result of cross-pollination, seeding errors, and/or commingling during harvest, storage and processing. The AP of GM material in conventional crops is at the centre of a heated international debate, due to the potential adverse effects on biodiversity of GM “escapes”. The Third Meeting of the Parties (MOP-3) to the Cartagena Protocol on Biosafety, which concluded last week in Brazil, resulted in the adoption of international documentation requirements for living modified organisms (LMOs) in the international trade of agricultural commodities.

What challenges do we face in terms of availability of GMO detection methods, validation and implementation? In the review: “Adventitious presence of GMOs: scientific overview for Canadian grains” researchers from the Canadian Grain Commission examine these issues. According to the authors, the main challenges for dealing with the AP of GM materials in non GM crops include:

The authors also identify a case study where testing procedures to detect the presence StarLink TM corn, which had been approved in the US but not in Canada, had minimal impacts on the Canadian grain industry. The factors that made this possible were: the existence of effective regulations and validated detection protocols; effective monitoring; industry willingness to comply; and effective cooperation between the relevant authorities involved.