Quantification of genetically modified maize MON 810 in processed foods

Maize MON 810 (Zea mays L.) represents the majority of genetically modified food crops. It is the only transgenic cultivar grown in the EU (European Union) countries and food products with its content higher than 0.9 % must be labelled. This study was aimed at impact of food processing (temperature, pH and pressure) on DNA degradation and quantification of the genetically modified maize MON 810. The transgenic DNA was quantified by the real-time polymerase chain reaction method. Processing as is high temperature (121 °C), elevated pressure (0.1 MPa) and low pH 2.25 fragmented DNA. A consequence of two order difference in the species specific gene content compared to the transgenic DNA content in plant materials used has led to false negative results in the quantification of transgenic DNA. The maize containing 4.2 % of the transgene after processing appeared to be as low as 3.0 % (100 °C) and 1.9 % (121 °C, 0.1 MPa). The 2.1 % amount of transgene dropped at 100 °C to 1.0 % and at 121 °C, 0.1 MPa to 0.6 %. Under such make up the DNA degradation of transgenic content showed up 2 or 3 time higher decrease a consequence of unequal gene presence. Such genes disparity is expressed as considerable decrease of transgenic content while the decrease of species specific gene content remains unnoticed. Based on our findings we conclude that high degree of processing might have led to false negative results of the transgenic constituent quantification. Determination of GMO content in processed foods may leads to incorrect statement and labelling in these cases could misleads consumers