title: Quantification of genetically modified soybeans using a combination of a capillary-type real-time PCR system and a plasmid reference standard.
abstract: Because the labeling of grains and feed- and foodstuffs is mandatory if the genetically modified organism (GMO) content exceeds a certain level of approved genetically modified varieties in many countries, there is a need for a rapid and useful method of GMO quantification in food samples. In this study, a rapid detection system was developed for Roundup Ready Soybean (RRS) quantification using a combination of a capillary-type real-time PCR system, a LightCycler real-time PCR system, and plasmid DNA as the reference standard. In addition, we showed for the first time that the plasmid and genomic DNA should be similar in the established detection system because the PCR efficiencies of using plasmid DNA and using genomic DNA were not significantly different. The conversion factor (Cf) to calculate RRS content (%) was further determined from the average value analyzed in three laboratories. The accuracy and reproducibility of this system for RRS quantification at a level of 5.0% were within a range from 4.46 to 5.07% for RRS content and within a range from 2.0% to 7.0% for the relative standard deviation (RSD) value, respectively. This system rapidly monitored the labeling system and had allowable levels of accuracy and precision.
authors.affiliation: Hiroshima Prefectural Institute of Public Health and Environment, Minami-ku, Hiroshima, Japan.
authors.forename: Akie
authors.initials: A
authors.lastname: Toyota
authors.forename: Hiroshi
authors.initials: H
authors.lastname: Akiyama
authors.forename: Mitsunori
authors.initials: M
authors.lastname: Sugimura
authors.forename: Takahiro
authors.initials: T
authors.lastname: Watanabe
authors.forename: Hiroyuki
authors.initials: H
authors.lastname: Kikuchi
authors.forename: Hisayuki
authors.initials: H
authors.lastname: Kanamori
authors.forename: Akihiro
authors.initials: A
authors.lastname: Hino
authors.forename: Muneharu
authors.initials: M
authors.lastname: Esaka
authors.forename: Tamio
authors.initials: T
authors.lastname: Maitani
mesh_terms: D030841:Food, Genetically Modified; D018745:Genome, Plant / Q000235:genetics; D030821:Plants, Genetically Modified; D010957:Plasmids / Q000235:genetics*; D016133:Polymerase Chain Reaction / Q000295:instrumentation / Q000379:methods*; D012015:Reference Standards; D015203:Reproducibility of Results; D013025:Glycine max / Q000235:genetics*; D013997:Time Factors