Page 41 - FoodFocusThailand No.193 April 2022

STRONG QC & QA

Polymerase Chain Reaction Technique (PCR) is a technique used the product food contains GMOs. The use of conventional PCR
to increase the quantity of DNA fragments area of interest, which techniques to determine whether food products are GMOs is a qualitative
indicates the presence of GMOs using thermocycler and the principle assay to check the product that contains GMOs or not. Quantitative
Self-replicating for the synthesis of desired site parts from the analysis is not possible.
interactions between DNA from food samples with short DNA Real-time PCR techniques have therefore been developed for use
fragments specific to the examined DNA fragment, the primer serves in quantitative investigations. By adding a specific DNA fragment to the
as the starting point for the DNA synthesis process. The PCR reaction fluorescent-labeled target DNA, known as a DNA probe, it fluoresces
initiates the first cycle of DNA synthesis from a gene or DNA fragment upon reaction participated in the PCR reaction and add a light source
in one molecule of interest; two genes or DNA fragments are obtained to produce the fluorescence of the PCR reaction products and the
in that region. After 30 to 40 cycles of this reaction, the number of fluorescence probe. This makes it possible to increase the quantity of
DNA fragments required increases by millions of times (2n increases required DNA fragments and report the result of the reaction at that time
when n is the number of reaction cycles). in every cycles of the reaction For the determination of GMOs in food
3. The results were examined by comparing the results obtained products by the Real-time PCR technique is analyzed together with
from the PCR reaction of the food samples’ DNA. Using Gel samples of GMOs used as standard substances with different weight
Electrophoresis, which is a biotechnological method used in the study ratios of GMOs, e.g., 0.01%, 0.1%, 1.0%, 5.0%, etc. to know the
of nucleic acids, such as DNA and RNA, in terms of separating the percentage of GMOs contained in the product.
study of some structures and properties by using the principle of This biomolecular technique can be used to determine the presence
movement of electric charges in an electric field to verify against PCR of GMOs in food products and raw materials used in food production. It
reaction results of genes or regions of interest specific to reaction helps consumers and food producers in the country have information in
primers. In the electric field, nucleic acids move from the negative choosing to consume or use raw materials to produce food products.
pole to the anode because it has a structure that contains a phosphate For export, it will help build confidence in customers in the quality of
group (PO -) that causes a negative charge. This principle is used to products. In addition, this technology is also applied in other biomarker
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separate or analyze nucleic acids, especially DNA, under an electric processes for purposes such as product adulteration detection, use in
field (Electrophoresis) through the medium is agar (Gel). The medium plant or animal breeding processes, and used to detect pathogenic
commonly used is agar type is the Agarose. After DNA is isolated on microorganisms in food products, etc.
agar, the agar plates are stained with Ethidium bromide, a substance
that glows under ultraviolet light.
Ethidium bromide binds to the DNA strand cause when the agar
sheets are placed under ultraviolet light. It will see the DNA bands More Information Service Info C006
glow and record images of DNA. It can be studied further using a
polaroid camera If the DNA band is found in the analysis food sample เอกสารอ้างอิง / References
and matches the DNA band used to identify GMOs, indicating that https://www.dss.go.th/images/st-article/bsp_11_2550_Genetical_Food.pdf

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