Research activities for the monitoring of genetically modified organisms in Japan*

The Japanese government introduced a labeling system for genetically modified (GM) foods. To ensure the authenticity of the labeling system, we have developed and validated detection methods for newly approved GM events. One was the development of quantitative analytical methods utilizing plasmid DNAs as calibrators, which enabled us to obtain an unlimited supply of calibrators of consistent quality and also to obtain a stable standard curve to quantify GM organisms (GMOs) in samples. The significance of quality control has been recognized among relevant stakeholders, and in response we launched a project to distribute certified reference materials (CRMs) to the users of our methods for the purpose of internal quality control. In addition to these activities, we have developed timeand cost-effective detection methods, such as a new screening method to simultaneously detect the sequence of Cauliflower mosaic virus 35S promoter (p35S) and the construct-specific sequence of GA21 event utilizing multiplex real-time polymerase chain reaction (PCR). We also developed a qualitative nonaplex PCR detection method, which allows the simultaneous detection of eight events of GM maize lines. Because the influx of any unapproved and unknown GMOs into the Japanese market is not permitted, we continue to explore this issue.