title: Detection limits of the strip test and PCR for  genetically modified corn in Brazil.
abstract: Brazilian legislation establishes a labeling limit for  products that contain more than 1% material from genetically modified organisms  (GMOs). We assessed the sensitivity of the lateral flow strip test in detection  of the GMO corn varieties Bt11 and MON810 and the specificity and sensitivity  of PCR techniques for their detection. For the strip test, the GMO seeds were  mixed with conventional seeds at levels of 0.2, 0.4 and 0.8% for Bt11, and 0.4,  0.8 and 1.6% for MON810. Three different methodologies were assessed and whole  seeds, their endosperm and embryonic axis were used. For the PCR technique, the  GMO seeds of each of the two varieties were mixed with conventional seeds at  levels of 20, 10, 5, 2, 1, and 0.5%. The seeds were ground and the DNA  extracted. For detection of the GMO material, specific primers were used for  MON810 and Bt11 and maize zein as an endogenous control. The sensitivity of the  strip test varied for both maize varieties and methodologies. The test was  positive for Bt11 only at 0.8%, in contrast with the detection limit of 0.4%  indicated by the manufacturer. In the multiplex PCR, the primers proved to be  specific for the different varieties. These varieties were detected in samples  with one GMO seed in 100. Thus, this technique proved to be efficient in  detecting contaminations equal to or greater than 1%.
authors: Departamento Agricultura, Universidade Federal de Lavras, Lavras, MG, Brasil. vivian_nascimento@hotmail.com
authors: V E
authors: VE
authors: Nascimento
authors: É V R
authors: ÉV
authors: Von Pinho
authors: R G
authors: RG
authors: Von Pinho
authors: A D
authors: AD
authors: do Nascimento
mesh_terms: D001938:Brazil; D017343:Genes, Plant / Q000235:genetics; D057230:Limit of Detection; D030821:Plants, Genetically Modified; D016133:Polymerase Chain Reaction / Q000379:methods*; D003313:Zea mays / Q000235:genetics*; D015028:Zein / Q000235:genetics
chemical_list: D015028:Zein