Event-specific PCR quantification of EU-authorized GM soybean events in soybean products

Abstract: The EU has implemented special regulatory requirements for food labeling with regards to genetically modified (GM) materials in order to ensure the informed choice of consumers. All food products containing more than 0.9% of authorized GM materials should be labeled. Therefore, the quantification of GM material in food products is very important to control food labeling. The aim of the present study was to detect and quantify the EU-authorized GM soybean events in 15 soybean products at the Bulgarian market without GM indication on the labels. A multiplex PCR method was applied to screen the products for the presence of genetically modified DNA, targeting three gene-specific (EPSPS, PAT and Cry1Ac genes) and one event-specific (DP 356043) DNA sequences. Positive samples were subjected to event-specific real-time PCR assay for quantification of GM soybean events MON 40-3-2, MON 89788, A2704-12 and A5547-127. Results indicated that 80% of the tested products contained MON 40-3-2, MON 89788 was detected in 13% of the samples and 20% of the tested products contained A2704-12. The amount of MON 40-3-2 was above the threshold of 0.9% in 1 sample, while the percentage of transgenic events MON 89788 and A2704-12 in all tested products was less than 0.9%. The initial screening and real-time PCR analysis showed that none of the tested products contained GM soybean events MON 87701, A5547-127, DP356043 and MON 87701xMON 89788. Therefore, based on the results from the study, only one of the analyzed products was falsely labeled with regards to GM ingredients.