The document describes a study that used nested PCR to detect the presence of Roundup Ready genetically modified soybean in various soy products sold in Brazil. DNA was extracted from samples of soy flour, soy protein isolate in infant formula, and soy milk powder. Nested PCR was performed using primers specific to CaMV 35S promoter and CP4 EPSPS sequences found in Roundup Ready soybean. The results showed that 4 of 6 soy flour samples and 15 of 25 soy milk powder samples tested positive for the Roundup Ready soybean, indicating that nested PCR is an effective way to detect genetically modified organisms in food and can help ensure proper food labeling.