doi:10.1094/CCHEM-84-2-0109 |  VIEW ARTICLE

Detection of Genetically Modified Soy in Doughs and Cookies.

Nicolas Gryson (1,2), Koen Dewettinck (3), and Kathy Messens (1). (1) University College Ghent, Department of Food Science and Technology, Faculty of Biosciences and Landscape Architecture, Ghent University Association, Voskenslaan 270, Gent 9000. (2) Corresponding author. Phone: +32 9 242 42 96. Fax: +32 9 242 42 93. E-mail: <nicolas.gryson@hogent.be> (3) Ghent University, Department of Food Quality and Food Safety, Laboratory of Food Technology and Engineering. Cereal Chem. 84(2):109-115. Accepted September 12, 2006. Copyright 2007 AACC International, Inc.

In many countries, including the European Union member states, Switzerland, Australia, New Zealand, and Japan, legislation has been set up for labeling of genetically modified organisms (GMOs) in food and feed products. To comply with these regulations, reliable detection methods are necessary. If the detection is based on DNA, a GMO analysis may contain several steps where qualitative and quantitative species-specific, GMO screening, GMO construct, and GMO line-specific polymerase chain reactions (PCRs) are used. A limit of detection (LOD) thereby defines to what extent a target molecule may be detected in a sample. In this study, cookies were made with variable levels of a soy sample containing 2 wt% Roundup Ready soy. For all PCRs described, detection limits based on dilution series and practical LODs were determined. The practical LODs are used to determine to what extent a GMO ingredient may be detected in a real food product. Results reveal that, due to the baking process, the overall DNA fragment length is reduced, rendering GMO analyses more difficult. Furthermore, Roundup Ready soy line-specific and real-time quantitative PCR are less sensitive than GMO screening PCRs, whereas just these PCRs are crucial in the decision-making process regarding the presence of GMOs in a food product. Moreover, high standard deviations and errors render the precise quantification of GMOs difficult.