Comparison of three DNA extraction methods for the detection and quantification of GMO in Ecuadorian manufactured food

BMC Res Notes. 2017 Dec 20;10(1):758. doi: 10.1186/s13104-017-3083-x.


Objectives: In Ecuador, food products need to be labeled if exceeded 0.9% of transgenic content in whole products. For the detection of genetically modified organisms (GMOs), three DNA extraction methods were tested in 35 food products commercialized in Ecuador. Samples with positive amplification of endogenous genes were screened for the presence of the Cauliflower mosaic virus 35S-promoter (P35S) and the nopaline synthase-terminator (Tnos). TaqMan™ probes were used for determination of transgenic content of the GTS 40-3-2 and MON810 events through quantitative PCR (qPCR).

Results: Twenty-six processed food samples were positive for the P35S alone and eight samples for the Tnos and P35S. Absolute qPCR results indicated that eleven samples were positive for GTS 40-3-2 specific event and two for MON810 specific event. A total of nine samples for events GTS 40-3-2 and MON810 exceeded the umbral allowed of transgenic content in the whole food product with the specific events. Different food products may require different DNA extraction protocols for GMO detection through PCR. Among the three methods tested, the DNeasy mericon food kit DNA extraction method obtained higher proportion of amplified endogenous genes through PCR. Finally, event-specific GMOs were detected in food products in Ecuador.

Keywords: DNA extraction; GMOs; PCR; Processed food.

Publication types

  • Comparative Study

MeSH terms

  • Caulimovirus / genetics
  • Crops, Agricultural / genetics*
  • Crops, Agricultural / virology
  • DNA, Plant / analysis*
  • DNA, Plant / isolation & purification
  • Ecuador
  • Food Contamination / prevention & control
  • Food Labeling / methods
  • Food, Genetically Modified / virology
  • Hazard Analysis and Critical Control Points / methods*
  • Plants, Genetically Modified / genetics*
  • Promoter Regions, Genetic / genetics
  • Zea mays / genetics
  • Zea mays / virology


  • DNA, Plant