Commercially available genetically modified micro organisms (GMO) are usually transgenic plants in which DNA from foreign species were artificially implemented.
These DNA sequences, mostly for insect, herbicide and/or insect resistance are enveloped in a frame of viral or bacteria; DNA sequences which server as promoters or terminators.
Different international and national legislation and labeling regulations requires multi-stage analysis, for which real-time PCR is the method of choice.
- The presence of GMOs can be screened by identifying the genetic sequence elements as 35S, NOS and FMV. Further genetic elements may be expected in future. 35S positive results should be confirmed for absence of natural contamination of the cauliflower mosaic virus using the CaMV system. Furthermore, the efficiency of the DNA preparation should be confirmed using plant DNA, when analysis a new matrix.
- For GMO positive samples the identification of the GMO event is of main interest to classify the food product in approved or illegal GMO. In Europe the legislation EC 1829/2003 and 1830/2003 describes the relevant regulations. Non-approved GMO products are not allowed to enter or to be produced or processed in Europe. A zero tolerance strategy is in force for Europe, while for feed samples a technical threshhold of 0.1% has been established (EC 628/2011). Food samples with a content of > 0.9% approved GMO per matrix has to be labelled.
- For approved GMOs in food samples quantification in the relevant range of approximately 0.9% is of main interest. The GMO Content in DNA copy numbers can be quantified relative to the plant matrix and the results will be given in percent.