In the last years, the increase in the cultivated area of genetically modified (GM) maize has become a reality. GA21, MON810 and MON 863 maize crops are some of the authorized maize events for food and feed under the European Union (EU) regulations. These crops of transgenic maize bring profit towards the conventional ones, as they confer resistence to some plagues and/or herbices. Concerning the raise of production and consumption of foodstuffs derived from genetically modified organisms (GMO), the EU has established new demand levels, including the labeling requirements when the product has GMO in proportion higher than 0.9% (Regulation (EC) Nº. 1829/2003)