The world wide production of genetically modified food (e.g. soy and corn) has steadily increased since the beginning of the 90’s.
Since the 1st of September 1998 all food products which are containing genetically modified organisms (GMO) must be labelled. As stated by the Council of Ministers of the European Union (EU), regulation for the labelling of Novel Food: Decision No. 1139/98/EC. Furthermore, since April 2004 the EU directive 1829/2003 came into force and determines the labeling threshold value at 0.9 % in EU for food and feed.
Qualitative GMO detection
According to national or regional regulations, zero tolerance applies to non-approved GMO events. As such, only qualitative tests are of interest for these products at the moment. The detection limit lies at 0.01 %, depending on the matrix and the application.
Regulation EC 619/2011 exists as a special rule for animal feeds. Provided that certain conditions are met (expired EU approval, approval in the country of origin, availability of tests and reference material, etc.), a technical threshold value of 0.1 % applies for non-approved GMO events. This is particularly significant for not always contamination-free imports of GMOs and GMO-free maize and soya.
Quantitative GMO detection
For respectively approved GMO events, there is the quantitative question of whether the product lies above the defined threshold values or mandatory labelling values.
In Europe, a value of 0.9 % applies to the GMO event in the respective plant matrix. Below that value, foodstuffs with technically unavoidable and coincidental contaminations of the GMO events do not need to be declared (EC 2829/2003 und EC2830/EC). The quantification occurs via the respective quantification of a GMO specific and plant matrix specific gene based on a respectively different calibration curve and the conversion to GMO plant /matrix DNA number of copies. This dimensionless unit multiplied by 100 yields the percentage value. The calibration curve is obtained via the dilution of a DNA standard and, on the basis of a defined GMO material, can also be specified precisely with an experimental correction factor.
A screening of plant extrinsic gene sequences that were infiltrated into the plants during GMO development provides efficient evidence of the presence of any possible GMOs.
The typically used gene sequences are:
This promoter, made from the cauliflower mosaic virus, is the most frequently used element. Plant samples that are only 35S positive can also be contaminated with the naturally occurring virus. False positive results can be ruled out by using the virus-specific CaMV (S2027) test.
The Nopalin Synthase Terminator (NOS) from Agrobacterium tumefaciens is often but not exclusively used in combination with 35S.
In lieu of 35S, the figwort mosaic virus promoter can also be used in GMOs.
The gene for phosphinotricin-N-acetyltransferase from Streptomyces hygroscopicus can enable a resistance against the herbicide glufosinate that is available under several different brand names.
This sequence denotes the transition from chloroplast transit peptide to 5-enolpyruvylshikimate-3-phosphate synthase from Arabidopsis thaliana and Agrobacterium spp. It enables a resistance against the herbicide glyphosate.
These and further parameters can either be combined in a modular way or used individually. The efficiency of the DNA preparation can be verified with a plant-specific PLANT Plus Kit (S2049). The PLANT Kit (S2056) is sufficient for the 4plex Kit with internal amplification control.
SureFood® is a modular system which is based on the 3 main components , amplification and detection. Each component consists of different modules. All modules are compatible. Thus, SureFood® is a highly flexible system which can be easily configured for different user specific applications. SureFood® is available as product and service as well.
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