+49 (30) 94 89 36 00 servicelab@congen.de


// GVO-Screening using Real-Time PCR

// Identification and Quantification of GMO


Corn, soy, canola, cotton, and sugar beet are currently among the most important genetically modified organisms (GMOs) worldwide. Many of these plants are primarily found in animal feed. For foodstuffs, on the other hand, only processed products of GMOs such as fats, oils, and starch are generally used. The labelling requirements for genetically modified food and feed in the European Union are regulated by Regulations (EC) No 1829/2003 and 1830/2003, which entered into force in April 2004. According to this, in the EU, the following are subject to labelling:

  • genetically modified organisms including soya, corn on the cob, tomato, potato, and linseed.
  • foodstuffs, animal feed, ingredients, and additives that are produced from GMOs (e.g. oil from soya or canola, starch from corn, sugar from sugar beet, and dextrose from corn starch).

Food and animal feed are exempt from the labelling requirement if they do not exceed a threshold value of 0.9% of genetically modified ingredients and this GMO content has demonstrably entered the product by chance or if this is technologically unavoidable. This threshold represents a relative value in relation to the food ingredient. For example, if a compound food contains an ingredient containing 1% corn, a maximum of 0.9% of this corn may come from genetically modified corn.

Also exempted from the labelling requirement:

  • food and ingredients produced with the aid of GMOs: e.g. products such as meat, milk, and eggs derived from animals that have received feed from genetically modified plants.
  • additives produced with the aid of genetically modified microorganisms: e.g. the flavour enhancer glutamate. Such additives are usually excreted by micro-organisms and then purified. In this case, the microorganisms used are legally regarded as processing aids. However, if the finished product still contains genetically modified microorganisms (in whole or in part), these additives have to be labelled.
  • Enzymes and other technical adjuvants: e.g. chymosin enzyme (used for thickening during cheese production) obtained with the aid of genetically modified micro-organisms.

The 0% tolerance applies to genetically modified food and feed with an ongoing safety assessment as well as to GMOs not authorised in the EU.

The variety of sample matrices and process steps influence the choice of suitable detection methods. The CONGEN ServiceLab is a specialist in the field of GMO analysis using real-time PCR. Specific and sensitive methods enable rapid analysis with reproducible results.

GMO Screening

  • 35S Promotor
  • BAR
  • CryIAb/CryIAc
  • FMV Promoter
  • NOS Terminator
  • NPT II
  • PAT Gene

GVO Canola

  • DP073496
  • GT73 (Roundup Ready™)
  • MON88302 (TruFlex™ / Roundup Ready Canola™)
  • MS8
  • RF3
  • T45

GMO Corn

  • 59122 (Herculex RW™)
  • Bt11
  • Bt176
  • CBH-351 (StarLink™)
  • GA21
  • MIR162
  • MIR604 (Agrisure RW™)
  • MON810 (YieldGard™)
  • MON863 (MaxGard™)
  • MON88017
  • MON89034
  • NK603 (Roundup Ready™)
  • T25 (LibertyLink™)
  • TC1507 (Herculex™)

GMO Soya

  • A2704-12 (LibertyLink™)
  • A5547-127 (LibertyLink™)
  • CV127 (Cultivance™)
  • DP305423 (Treus / Plenish™)
  • GTS 40-3-2 (Roundup Ready™)
  • MON87701
  • MON87708 (Genuity RR2Extend™)
  • MON87769
  • MON89788 (RR2Yield™)

Additional GMO

  • BT63 Rice
  • CaMV (Cauliflower Mosaic Virus)
  • CMS (CMS Ogura in Brassica vegetables)
  • FP967/CDC Triffid linseed
  • LL601 Rice (LibertyLink™)
The analysis comprises the following steps:
  • GMO Screening
  • GMO Identification
  • GMO Quantification

Homogenization and DNA Extraction

You send a representative part of the sample material to our service laboratory. The sample is homogenized, and the DNA is extracted in duplicate. Of course, appropriate controls will be carried out:

  • The negative extraction control as an indication of buffer contamination or carry over during extraction.
  • The positive extraction control (as proof of the functionality of the method used) is carried out in the form of a lot-dependent process control.


Real-time PCR

The extracted sample DNA can be analysed for up to six parameters using real-time PCR. In qualitative procedures, negative, inhibition, and positive controls are routinely used. If the controls show the expected results, you will receive a test report with the corresponding results and the system-specific detection limit. Please note that the determination is not matrix-specific.

Qualitative DNA Detection

Screening – GMO analysis begins with a general screening. This involves testing for different DNA sequences, which are frequently used in different GMOs. This provides initial information on genetically modified material in food or animal feed. Common screening elements include the 35S and FMV promoter as well as the NOS terminator.

Identification – In the event of a positive screening result, the GMO is identified in a second step by means of construct- or event-specific evidence. For varieties not authorised in the EU, the GMO analysis is completed with the identification because a 0% tolerance applies.

Relative quantitative DNA detection

If a sample has been tested qualitatively positive for one or more GMOs or if expected GMOs are to be investigated, they can be quantified using real-time PCR. Such quantification may be necessary for varieties with EU approval in order to decide on the labelling requirement of the food/feed. The quantitative method we offer is based on relative quantification. The design or event-specific GMO detection contains two PCR systems: a detection system and a reference system. The relative GMO content in the samples is calculated from the ratio of the GMO detection gene to the reference gene. The copy numbers of the sample and the positive control are determined with the aid of a standard series. Both the sample matrix and the degree of processing of the sample can influence the quantitative result and the determination limit. For this detection, the determination limit is sample-specific. For swabs, sponges, and comparable swab samples, a quantitative statement is generally not possible.

You are Intersted in GMO Analyses?

For your inquiry you can use our online form. If you need an overview of LOD and LOQ for all GMO methods, please send an e-mail to info@congen.de.