Dna detection methods

PCR and real-time PCR are the most commonly used techniques for DNA detection. Both are used qualitatively to identify allergenic substances in food by amplifying a specific part of the DNA sequence of the species or coding allergen.

It is controversial to detect food allergens through DNA detection technology, because these methods do not detect target allergens but DNA markers, and the DNA markers may have nothing to do with the actual allergen content in the food.

Examples of products that can cause this are milk powder or egg powder, which are foods formulated with protein-rich components.

To achieve success in the analysis using this type of technique, it is necessary to take into account several factors such as the presence and quality of the compounds that interfere in the preparation of DNA, as well as the amount of DNA in the sample.

The assay components for performing analysis using PCR techniques are usually commercially available and easy to develop, which is an advantage over ELISA technology.

In addition, ELISA assays are not available for certain legislated allergens such as celery, with PCR technology being the only option for analysis and detection.

In foods such as tomato sauce, where there is an acidic environment, DNA is very unstable, representing a disadvantage for detection by PCR techniques. In such circumstances, detection methods based on protein or peptide detection should be used whenever possible.

Another factor that can cause false positive results is the cross-contamination that can occur in laboratories, through contact of the PCR mixture with small amounts of target DNA from previous assays.

Another disadvantage of this type of technique is that it can detect allergenic components in one product from the same animal, while not in other products from the same animal. Such as allergenic beef and allergenic milk or allergenic chicken and allergenic egg, where PCR tests do not distinguish between the DNA of one and the DNA of the other. Egg is a food that, even having a high allergenic potential caused by the presence of specific proteins, should not be tested by PCR techniques, because it has low levels of DNA