Nested PCR detection of genetically modified soybean in soybean flour, infant formula and soymilk

Due to the Brazilian market introduction of the genetically modified (GM) crop Roundup Ready™ (RR) soybean, the ability to detect GM crops has become a legal necessity. In order to detect the presence of RR soybean, a polymerase chain reaction (PCR) amplification method was evaluated for the detection of RR in soybean mixtures and commercially available soy flour, infant formula and soymilk powder. To detect the presence of RR soybean, a nested PCR resulted in an amplicon of 169 bp, present for all soybean mixed samples containing 0.01–10% GM soybean and absent for 0% GM soybean. None of the analysed infant formulas showed a positive signal after the nested PCR; four out of six soy flour samples and 15 out of 25 soymilk powder samples were positive for the presence of RR soybean. Results show that the nested PCR method used is adequate to determine the presence of GM soybean in the presented products.