GMO Analysis Guide: Methods, Legislation, Sampling, Reporting

GMO analysis is the general name given to laboratory tests performed to determine whether DNA sequences originating from genetically modified organisms are present in a sample and, where necessary, to identify which GMO event is present or at what level it is present. In practice, these analyses are mostly carried out using PCR-based methods and may consist of different stages such as screening, confirmation and quantification.

In Turkey, the official approach to GMO analysis is based on verification, method suitability and the production of reliable results. In the EU, authorization, monitoring, labelling and reference method infrastructure are supported by a separate legislative and laboratory system.

This guide explains step by step what GMO analysis is, why it is requested, which products it is applied to, the laboratory process, Turkish and EU legislation, sampling rules and the logic behind report interpretation.

What is GMO analysis?

GMO analysis is the laboratory investigation of specific genetic elements that result from biotechnological intervention in the genetic structure of a product. The main purpose is to detect the presence of GMO-related sequences in the sample and, if necessary, to determine which genetic event this presence belongs to.

The analysis is not only used to provide a “present/absent” answer. Where required, it can also be used to assess quantity according to specific thresholds.

In practice, GMO analysis is usually considered in three layers: first, general screening is performed; then suspicious or positive findings are confirmed; and finally, if necessary, event-specific and quantitative analysis is applied. This structure is the most common workflow in both official controls and commercial laboratory services.

Why is GMO detection performed?

GMO detection is performed for regulatory compliance, verification of product claims, management of import-export risks, supply chain control and official inspection purposes. Especially in product groups that may contain GMOs, analysis becomes critical for determining whether the product complies with the rules of the relevant country or market.

In Turkey, the Ministry of Agriculture and Forestry clearly states that official controls are carried out for foods that may contain GMOs in order to ensure food safety. In the same official statement, it is stated that no gene has been approved for food use; therefore, the use of GMOs and GMO products for food purposes is prohibited, and the import of GMO products for food use is not permitted.

For this reason, GMO analysis in Turkey is not only a technical laboratory procedure but also a strong regulatory compliance tool.

In the EU market, the purpose is somewhat different. The system is not based entirely on prohibition, but on authorization, traceability, labelling and compliance. Therefore, for businesses placing products on the EU market, GMO analysis plays an important role in distinguishing authorized products from unauthorized ones and in meeting labelling obligations.

Which products require GMO analysis?

GMO analysis is most commonly required for soy, corn, canola, cotton and products containing their derivatives. These matrices are also clearly highlighted within the scope of GMO analysis in laboratory announcements affiliated with the Ministry.

However, the need for analysis is not limited to raw agricultural products. Processed foods, feeds, flour and protein-based mixtures, products containing additives and some seed samples may also be evaluated for GMOs.

The critical point here is whether DNA of analyzable quality remains in the sample. As the level of processing increases, DNA fragmentation may also increase; therefore, method selection and result interpretation must be performed more carefully. This second sentence is a technical inference based on the laboratory approach reflected in official sources.

How is GMO analysis performed?

GMO analysis typically proceeds in the following order: sample acceptance, homogenization, DNA extraction, DNA quality control, PCR-based screening, confirmation if necessary, quantification if necessary, result evaluation and reporting.

The Ministry’s verification guide for GMO analyses is based on demonstrating the suitability and reliability of the method used by the laboratory. In the EU reference system, validated methods and reference laboratory infrastructure are important.

The first technical step is to obtain DNA of sufficient quality from the sample. Then, the suitability of the DNA for analysis is confirmed using plant-specific or matrix-specific internal control targets.

In the next step, common genetic elements associated with GMOs are screened. If the screening result is positive, or if the risk profile requires it, event-specific confirmation is performed. If the product and legislation require it, quantification is also included in the final stage.

In short, “GMO analysis” is not a single test but a decision tree consisting of several interconnected laboratory stages.

Differences between PCR, Real-Time PCR and event-specific analysis

PCR is a fundamental molecular biology method used to amplify specific DNA regions and show whether that region is present in the sample. In GMO analysis, conventional PCR may be used mainly in a qualitative approach, meaning “detected / not detected.”

Real-Time PCR, on the other hand, allows the amplification process to be monitored in real time. This provides high sensitivity and, under certain conditions, enables quantification. The Ministry’s verification guide also refers to qualitative and quantitative PCR-based GMO analyses.

Event-specific analysis differs from general GMO screening because it directly targets a specific genetic event. In the EU, the EURL GMFF and GMOMETHODS infrastructure supports the validation and reference use of such event-specific methods. Therefore, event-specific analysis is closer to answering the question “Which GMO event is present?” rather than “Is there a GMO trace in this sample?”

What are screening tests and confirmation tests?

A screening test is the first stage that performs a preliminary investigation of common genetic elements associated with GMOs in the sample. In practice, markers such as p35S, tNOS and pFMV may be used for this purpose; these markers are also referenced in official laboratory content.

The logic of screening is as follows: instead of searching for all possible events one by one, the laboratory first screens for commonly used genetic building blocks associated with GMOs. If the result is negative, the process is usually closed at this stage. If the result is positive or suspicious, the second stage begins.

A confirmation test verifies the screening finding using more specific targets. At this stage, event-specific methods, additional PCR designs or quantitative approaches may be used.

Especially in cases of official control, export or dispute, the confirmation test is important for the legal and technical robustness of the report. This final sentence is an inference based on the combined interpretation of legislation and the validated method approach.

How does GMO legislation work in Turkey?

Turkey’s approach to GMOs on the food side is highly restrictive. According to the official statement of the Ministry of Agriculture and Forestry, no gene has been approved for food use. Accordingly, the use of GMOs and GMO products for food purposes is prohibited, and the import of GMO products for food use is not permitted.

Therefore, GMO analysis in food products in Turkey is often evaluated from the perspective of “market compliance” or “official control.” In other words, the analysis result is not merely a technical finding; it may also be a direct indicator of regulatory compliance.

The Ministry also states that domestic official controls for foods likely to contain GMOs are carried out effectively.

The practical point to note here is that the legal framework for food and feed applications in Turkey is not the same. Users often confuse these two areas. This guide is food-focused; separate authorization and evaluation structures may apply on the feed side. EU and Commission sources also clearly show the regulatory distinction between food and feed.

GMO compliance in the EU market

In the EU, the system for genetically modified food and feed operates under Regulation (EC) No 1829/2003. This regulation sets out the rules for the authorization, supervision and labelling of genetically modified food and feed. Its purpose is to ensure a high level of protection for human and animal health, the environment and consumer interests.

In the EU, compliance is not based solely on the question “Is there a GMO or not?” It is also important whether the product is authorized, which event it contains, whether labelling is required and whether it can be verified using reference methods.

For this reason, GMO analysis for companies working with the EU is generally handled through a screening plus event-specific confirmation approach. The EURL GMFF and GMOMETHODS infrastructure also provides the official technical backbone that supports this need.

For exporting companies in particular, the most critical point is distinguishing between events accepted by the target market and the risk of unauthorized events. This is not only a laboratory technique issue but also a matter of regulatory interpretation and supply chain management. This assessment is an inference based on the combined interpretation of EU legislation and the reference laboratory system.

Sampling and analysis process

The first requirement for a reliable result in GMO analysis is the correct sample. The sample must represent the product, be collected in a way that prevents cross-contamination, be sent in appropriate packaging and maintain traceability until it reaches the laboratory.

No matter how strong the molecular analysis is, an incorrect or poorly representative sample may lead to an incorrect result. This sentence reflects a fundamental principle derived from the logic of laboratory verification.

In practice, the process usually proceeds as follows:

The sample is accepted, recorded, divided into sub-samples if necessary, homogenized, DNA is extracted, quality controls are performed, screening PCR is applied, confirmation and quantification stages are carried out if needed, and then the result is reported within the framework of legislation and method limits.

In processed products, matrices exposed to high heat or advanced processing, or multi-component foods, the sampling process becomes even more critical. This is because DNA quality may decrease, directly affecting method sensitivity. This statement is an expert inference based on the basic technical logic of PCR-based GMO analysis and should be evaluated by the laboratory on a matrix-specific basis.

How should the report be read?

When reading a GMO analysis report, the first points to check are:

sample description, method applied, targeted marker or event, whether the result is qualitative or quantitative, detection limit, interpretation section and compliance assessment.

In qualitative reports, the result is usually expressed as “not detected,” “detected” or similar wording. In quantitative reports, the result may be given as a percentage or relative ratio.

However, reading this result alone is not sufficient. It is also necessary to see which target the report was based on and within which method limits the result was produced.

For example, screening positivity alone does not always mean that a specific event has been definitively identified. In such cases, confirmation or event-specific test results become decisive.

Similarly, a “negative” result means that the sample is negative for the targets included within the scope of the analysis; it does not automatically provide a conclusion about targets that the laboratory did not screen for. These two sentences are a technical interpretation of the screening and confirmation architecture.

The final step in report interpretation must always be the regulatory context. Interpretation on the food side in Turkey may not be the same as interpretation in the EU market. Therefore, especially in import, export or contract manufacturing scenarios, the report should be read not only as a technical finding but also in terms of target market compliance.

Frequently asked questions

Can GMO analysis prove that a product is GMO-free?

The analysis provides an assessment within the targets studied and the limits of the method used. Therefore, the correct wording is generally “not detected within the scope of the applied method and analysis coverage.”

Is the same method used for every product?

No. Matrix, processing level, DNA quality and target market requirements affect the method. Screening, confirmation and event-specific approaches may differ depending on the product.

If the screening result is positive, is the product definitely GMO?

Screening positivity may require further confirmation. A definitive interpretation is usually made after specific confirmation or event-specific analysis.

Are Turkey’s and the EU’s approaches the same?

No. Turkey’s approach on the food side is more restrictive, while the EU has a system based on authorization, monitoring and labelling.

Why might companies exporting to the EU need event-specific analysis?

Because compliance in the EU is not only about the general presence of GMOs, but also about monitoring specific authorized events and confirming them with reference methods.

Can GMO analysis also be performed on processed products?

Yes. However, the level of processing of the matrix may affect DNA quality. This directly affects method selection and result interpretation.