PCR detection of genetically modified soya and maize in foodstuffs

The detection of genetically modified foodstuffs is becoming both a food sa les and legal necessity. This study reports a rapid DNA extraction/PCR-base d method for the detection of genetically modified soya (GMS) and maize (GM M) in mixed samples of transgenic and unmodified soybeans and maize kernels , and a variety of processed samples including soya flour, soya protein iso lates, extruded defatted soya, acid- and alcohol-precipitated soya concentr ates, soya lecithin, maize grits, seasoned corn puffs and salted corn chips . The presence of GMS DNA was determined with two pairs of primers directed towards different GMS target sequences and GMM by one primer pair. In addi tion, a multiplex PCR reaction which utilises an internal positive control was developed for both genetically modified organisms (GMOs). Results indic ated that the methods are sensitive and specific enough to detect GMS down to a level of 0.01% dry weight in single-product PCRs and 0.1% in multiplex PCRs and GMM down to 0.001% dry weight in single-product PCRs and 0.01% in multiplex PCR. The methods are considered to represent a viable route for the commercial detection of GMS and GMM in foodstuffs.