Determination of unprocessed genetically modified soybean in foods using simplex and duplex real‐time PCR with an internal standard

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 ⁄ 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.

A PCR assay to detect trace amounts of soybean in meat sausages

“…, 2007), quantitative real‐time PCR (Andersen et al. , 2006; Brod & Arisi, 2008; Harikai et al. , 2009; Moriuchi et al.…”

Detecting adulteration of Dendrobium officinale by real‐time PCR coupled with ARMS

“…It has also been used for the identification of food species, such as fish, pork, sausages, wheat and Soybean (Eugster et al. , 2008; Brod & Arisi, 2009; Harikai et al. , 2009; Sanchez et al.…”

“…Real-time fluorescent quantitative polymerase chain reaction (rt-PCR), one of the recently emerging techniques, has been widely used in genetic engineering and medical fields (Bustin et al, 2005). It has also been used for the identification of food species, such as fish, pork, sausages, wheat and Soybean (Eugster et al, 2008;Brod & Arisi, 2009;Harikai et al, 2009;Sanchez et al, 2009;Sonnante et al, 2009;Farrokhi & Joozani, 2011), but not yet for Dendrobium products. In this study, real-time PCR was used in identification of herb commercial products for the first time.…”