Determination of unprocessed genetically modified soybean in foods using simplex and duplex real-time PCR with an internal standard |
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Authors: | Naoki Harikai ,Shin Saito,Atsuko Tanaka,& Kenji Kinoshita |
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Affiliation: | School of Pharmacy and Pharmaceutical Sciences, Mukogawa Women's University, 11-68 Koshien Kyuban-cho, Nishinomiya, 663-8179 Hyogo, Japan; Sumitomo Bakelite Co., 1-1-5, Murotani, Nishi-ku, Kobe, 651-2241 Hyogo, Japan |
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Abstract: | 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/wtf) 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/wtf 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/wtf GMO). The average GMO amount ranged from 0.35% to 0.63% w/wtf. 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. |
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Keywords: | DNA extraction method food analysis genetically modified organism polymerase chain reaction Roundup ReadyTM soybean |
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