Survey of compliance with labeling legislation in food containing GMOs in Brazil

DNA extraction techniques compared for accurate detection of genetically modified organisms (GMOs) in maize food and feed products

“…The GMO screening results demonstrate the presence of GM material in maize foodstuffs and feeds that are commercially sold in local Turkish markets without any indication for consumers, in spite of the labelling regulations. The use of GM materials in food and feed industries was similarly reported by other others (Branquinho et al 2010;Herzallah 2012). Conversely, our results differed from the recent report of Arun et al (2013) in which 32.6 % of maize samples tested were positive for GMOs, as well as Gurakan et al (2011) who found that 11 of the total 31 Turkish maize foodstuff samples (35 %) tested were GMO positive; but were similar to the results of Greiner and Konietzny (2008) who found 8-11 % of GM in 100 Brazilian maize products, which may indicate thaand who suggested that the prevalence of GM maize material in food and feed products depends on the year.…”

“…With regard to the dilution test (5 % Bt11 DNA), the correlation coefficient (R 2 ), slope of the regression line and the PCR efficiencies of DNA amplification from each of the five extraction methods were not statistically different from each other (p>0.05) and in all cases distortion from the normal distribution was not observed with the Shapiro-Wilk Test for normality and Levene Test for uniformity of variances (Table 3). The higher degree of correlation of the calibration curves than the minimum acceptable coefficient (R 2 >0.98) emphasises the adequacy of all extraction methods for quantification (Branquinho et al 2010). Furthermore, the slightly lower R 2 values obtained from the Foodproof and Genespin methods suggests that, when DNA yields are lower, the presence of any impurities leads to greater variability in plantderived DNA target amplification in these methods.…”

“…Since a prerequisite to GMO detection by PCR is the ability to obtain high quality extracted DNA, the choice of DNA extraction method is of critical importance for successful application of these methods (Tung-Nguyen et al 2009;Smith et al 2007). The different extraction methods can result in DNA showing different levels of purity and yield in different types of food matrices and feed, necessitating the validation of DNA extraction methods on a case-by-case basis (Tung-Nguyen et al 2009;Gryson 2010;Branquinho et al 2010).…”

Use of real-time PCR to evaluate two DNA extraction methods from food

“…There are some published studies about the detection and quantification of the amount of transgenic material present in Brazilian processed food (BRANQUINHO; FERREIRA; CARDARELLI-LEITE, 2010;BROD et al, 2007;BROD;CARDARELLI et al, 2005;DE MELO;, DINON, 2010FERREIRA;BRANQUINHO;CARDARELLI-LEITE, 2009;GREINER;KONIETZNY, 2008;MARCELINO;GUIMARÃES;BARROS, 2007), but none of these products that contain modified GMO above the threshold level had been appropriately labeled, reinforcing the need for continous analyses in processed food products.…”

Detection of genetically modified maize events in Brazilian maize-derived food products

“…4860 of April 2003(BRASIL, 2003) to ensure that consumers are properly informed about the presence of genetically modified ingredients in the food products. Since then, some studies on the detection and quantification of levels of genetically modified soybean and maize in Brazilian food products have been published (BRANQUINHO; FERREIRA; CARDARELLI-LEITE, 2010;BROD et al, 2007;BROD;CARDARELLI et al, 2005;DINON et al, 2010;FERREIRA;BRANQUINHO;CARDARELLI-LEITE, 2009;GREINER;KONIETZNY, 2008;MARCELINO;GUIMARÃES;BARROS, 2007). The methods used are based on the Polimerase Chain Reaction (PCR), which is the analytical system widely adopted in GMO detection, and the quantifications are based on real-time PCR (qPCR) that targets different genetic elements, including the cauliflower mosaic virus 35S promoter (P-35S) ( VAN DEN EEDE, 2010).…”