文摘
The applicability of quantifying genetically modified (GM) maize and soy to processed foods wasinvestigated using heat treatment processing models. The detection methods were based on real-time quantitative polymerase chain reaction (PCR) analysis. Ground seeds of insect resistant GMmaize (MON810) and glyphosate tolerant Roundup Ready (RR) soy were dissolved in water andwere heat treated by autoclaving for various time intervals. The calculated copy numbers of therecombinant and taxon specific deoxyribonucleic acid (DNA) sequences in the extracted DNA solutionwere found to decrease with time. This decrease was influenced by the PCR-amplified size. Theconversion factor (Cf), which is the ratio of the recombinant DNA sequence to the taxon specificDNA sequence and is used as a constant number for calculating GM% at each event, tended to bestable when the sizes of PCR products of two DNA sequences were nearly equal. The resultssuggested that the size of the PCR product plays a key role in the quantification of GM organisms inprocessed foods. It is believed that the Cf of the endosperm (3n) is influenced by whether the GMoriginated from a paternal or maternal source. The embryos and endosperms were separated fromthe F1 generation seeds of five GM maize events, and their Cf values were measured. Both paternaland maternal GM events were identified. In these, the endosperm Cf was lower than that of theembryo, and the embryo Cf was lower than that of the endosperm. These results demonstrate thedifficulties encountered in the determination of GM% in maize grains (F2 generation) and in processedfoods from maize and soy.Keywords: Zea mays; Glycine max; genetically modified; MON810; Roundup Ready; processed food;endosperm; embryo; heat treatment; GMO detection; quantitative analysis