Applicability of quantitative PCR to soy processed foods containing Roundup Ready Soy

Detection methods for genetically modified organisms (GMO) have been developed among countries, but there are still no practical quantitative methods for the processed foods. Although the quantitative methods in the Japanese standard are now targeted at raw grain, we examined whether the methods may also be applied to processed soy foods. The Roundup Ready Soy (RRS) in soy products by our own or professional making were quantified using real time PCR, and we compared the RRS content with that in raw soybeans. As a result, sufficient copy numbers of the lectin and introduced gene were obtained for quantification from all the soy products. Almost all items showed no significant differences in the RRS content. These findings suggested that the Japanese official quantitative method might be useful for screening in some soy products.