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Determination of unprocessed genetically modified soybean in foods using simplex and duplex real‐time PCR with an internal standard
Author(s) -
Harikai Naoki,
Saito Shin,
Tanaka Atsuko,
Kinoshita Kenji
Publication year - 2009
Publication title -
international journal of food science and technology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.831
H-Index - 96
eISSN - 1365-2621
pISSN - 0950-5423
DOI - 10.1111/j.1365-2621.2009.01996.x
Subject(s) - genetically modified organism , duplex (building) , biology , food science , chromatography , chemistry , dna , gene , genetics
Summary We developed a method using an internal standard to determine the amount of unprocessed genetically modified organisms (GMO) in foods as GMO weight per weight of total food (w/w tf ) using real‐time PCR. Food samples were spiked with an internal standard, a ColE1 plasmid, and DNA was extracted from the samples using a silica membrane‐type kit and analysed using real‐time PCR. The relationship between the GMO amount and the copy number ratio of the transgene to ColE1 in 0.1–5% w/w tf GM soybean powders was found to have a correlation coefficient ( r ) of 0.97. GMO was quantified in food samples spiked with GM soybean (final amount 0.5% w/w tf GMO). The average GMO amount ranged from 0.35% to 0.63% w/w tf . The results show that our method should be useful for quantifying unprocessed GMO in foods. We also developed a duplex assay, which is simpler and more accurate than the simplex assay.