Detection of genetically modified rice: collaborative validation study of a construct-specific real-time PCR method for detection of transgenic Bt rice

A collaborative trial study has been conducted for validation of an extraction method and a subsequent real-time PCR for detection of a transgenic Bt rice line (‘Bt63’) in rice products originating from China. A total of 17 laboratories participated in the study and each laboratory received 16 coded samples comprising of rice grain flours, rice noodle flours and plasmid DNAs. Of the accepted results all Bt63-positive rice grain samples (0.1 or 0.05% w/w) and all rice noodle samples prepared from marketed rice products were detected correctly. The result demonstrates that ‘Bt63’ rice is detectable even at low relative mass concentrations of 0.05%. The absolute LOD determined with plasmid DNA samples showed to be at least five copies of the ‘Bt63’ target sequence. The data provided in this study show that the method is fit-for-purpose to inspect Chinese rice products for the presence of EU-unauthorised rice lines carrying the ‘Bt63’ construct.