LIPP ET AL.: JOURNAL OF AOAC INTERNATIONAL VOL. 82, No. 4,1999 923 FOOD COMPOSITION AND ADDITIVES IUPAC Collaborative Trial Study of a Method To Detect Genetically Modified Soy Beans and Maize in Dried Powder 1 MARKUS LIPP European Commission, Directorate General (DG) Joint Research Center, Institute for Health and Consumer Protection, Food Products Unit, 1-21020 Ispra(Va), Italy PETER BRODMANN Kantonales Labor Basel, Postfach, CH-4012 Basel, Switzerland KLAUS PTETSCH Chemische Landesuntersuchungsanstalt Freiburg, Bissierstrasse 5, D-79114 Freiburg, Germany JEAN PAUWELS European Commission, DG Joint Research Center, Institute for Reference Materials and Measurements, Retieseweg, B-2440 Geel, Belgium ELKE ANKLAM European Commission, DG Joint Research Center, Institute for Health and Consumer Protection, Food Products Unit, 1-21020 Ispra(Va), Italy Collaborators: T. Borchers, G. Braunschweiger, U. Busch, E. Eklund, F.D. Eriksen, J. Fagan, A. Fellinger, H. Gaugitsch, D. Hayes, C. Hertel, H. Hortner, P. Joudrier, L. Kruse, R. Meyer, M. Miraglia, W. Miiller, P. Philipp, B. Popping, R. Rentsch, J. Sawyer, M. Schulze, G. van Duijn, S. Vollenhofer, A. Wurtz This paper presents results of a collaborative trial study (IUPAC project No. 650/93/97) involving 29 laboratories in 13 countries applying a method for detecting genetically modified organisms (GMOs) in food. The method is based on using the polymerase chain reaction to determine the 35S promoter and the NOS terminator for detection of GMOs. Reference materials were produced that were derived from genetically modified soy beans and maize. Correct identification of samples con- taining 2% GMOs is achievable for both soy beans and maize. For samples containing 0.5% genetically modified soy beans, analysis of the 35S promoter resulted also in a 100% correct classification. How- ever, 3 false-negative results (out of 105 samples analyzed) were reported for analysis of the NOS ter- minator, which is due to the lower sensitivity of this method. Because of the bigger genomic DNA of maize, the probability of encountering false-negative results for samples containing 0.5% GMOs is greater for maize than for soy beans. For blank samples (0% GMO), only 2 false-positive re- sults for soy beans and one for maize were re- ported. These results appeared as very weak sig- nals and were most probably due to contamination of laboratory equipment. Received July 20, 1998. Accepted by JL December 23, 1998. 1 Project 650/93/97 of the Commission on Food Chemistry. T he European Parliament and the Council of the Euro- pean Union (EU) have demanded in the Novel Food Regulation (EC/258/97) a clear and mandatory labeling of genetically modified organisms (GMOs) in food (1). Be- cause the Roundup-Ready soy beans and the BT-176 maize were put on the market before Regulation EC/258/97 came into force, labeling of products derived from these GMOs is demanded by the separate Council Regulation 1139/98 (2). According to these regulations, labeling of food and food in- gredients containing GMOs is mandatory, but not yet for food additives or food flavorings. Methods for specific detection of the most economically important GMOs are already available (3-7). However, to cope with the growing number of GMOs in different food matrixes, there is a need for a screening method indicating the presence or absence of known GMOs in general. Such a method would allow discrimination of sam- ples containing GMOs from those that are free of GMOs. GMO-containing samples can then be analyzed further to de- termine the strain of GMO present. This approach could facili- tate considerably the work of regulatory authorities. Recently, a screening method was published (8) that is based on the detection of 2 genetic elements, the 35S promoter and the NOS terminator, by means of the polymerase chain re- action (PCR). These 2 genetic elements are important for the expression of genes and are present in nearly all genetically modified plants (9,10). The method seems well suited to serve as a screening method to detect the presence of GMOs. However, it will not allow identification of the GMOs present because these genetic elements are incorporated in numerous GMOs. Downloaded from https://academic.oup.com/jaoac/article/82/4/923/5683736 by guest on 06 February 2022