GMO Labelling Detection Methods: Having to Draw a Blurry Line

A GMO – e.g. a transgenic plant – can only receive authorisation in the EU if customised tests exist to detect it.

Each authorised genetically modified plant requires its own test custom tailored to that specific GM plant (event), e.g. Bt11 maize, MON812 maize, or GR73 rapeseed.

The company submitting a GMO for approval is required to provide the necessary information needed develop a test specific to that particular GMO.

The EU’s Community Reference Laboratory: Standards for detection methods

The European Commission has set up the Community Reference Laboratory (CRL), which is responsible for reviewing detection procedures and subsequently putting forth standardised testing protocols for use throughout the EU. Other reference laboratories from various Member States also play a part in the process. All test methods that have been accepted or are currently being evaluated can be found on the CRL’s website.

Community Reference Laboratory: Validation of detection methods for GM food and feed.

Detecting GMOs almost always means using a technique called PCR. PCR involves three basic steps. (1) Custom designed bits of DNA called primers chemically recognise and specifically match up only with the novel gene in a GMO. (2) If primers find the target DNA sequence, a rapid chain reaction is triggered (PCR: polymerase chain reaction ). This chain reaction effectively copies the target fragment millions of times. (3) With so many copies, this specific DNA fragment can now be detected. If the copied fragments are present, we know that the GMO of interest was in the sample.

GMO detection: Exact quantities cannot be determined

For a long time, only qualitative PCR tests were possible: they could only tell whether or not a sample contained the GMO. Quantitative tests that can tell how much of a GMO is present are a relatively recent development. Only after the development of these procedures did the verification of thresholds become possible.

The best techniques we have available today, however, are still prone to error.

• A quantitative evaluation is only possible when enough DNA can be extracted from the item being tested. If there is not enough DNA, amplifying with PCR will not give useful results. This problem is often the case for soy lecithin. Although it is possible to isolate DNA from soy lecithin, there is not enough to find out how much of the lecithin was made from GMOs.

• In some cases, quantitative tests can yield highly variable results. Extraction, mixing, and processing throw in variables that take away from the precision of the test. Even though detection methods are carefully standardised across Europe, different labs can come up with different results for the same test.

• When products contain intact pieces of DNA, tests for GMO content can still be carried out. However, these fragments often get completely erased when a product is processed (due to pressure, heat, or chemicals). This is often the case for refined oils from soy or rapeseed. To be able to determine if GM raw materials were used, monitoring agencies are limited to conducting tests earlier on in production or investigating documentation accompanying the raw materials.

See also on GMO-Compass:

• EU: GMO Regulation System