Determination of fish origin by using 16S rDNA fingerprinting of bacterial communities by PCR-DGGE: An application on Pangasius fish from Viet Nam

The determination of geographical origin is a demand of the traceability system of import–export food products. One hypothesis of tracing the source of a product is by analysing in a global way the bacterial communities of the food samples after their exportation. For this purpose, molecular techniques employing 16S rDNA profiles generated by PCR-DGGE were used to detect the variation in bacterial community structures of Pangasius fish from An Giang province, South Viet Nam harvested in different aquaculture farm and during two different seasons, the rainy season and the dry season. When the 16S rDNA profiles were analysed by multivariate analysis, distinct microbial communities were detected. The band profiles of the fish bacteria from different farms are different and are specific for each location and could be used as a bar code to certify the origin of the fish. When band profiles within the same location at different seasons were compared, we also observed the difference banding pattern for each season. Some common bands were noted which are stable throughout the seasons. These bands can be used as specific markers for this specific location. This method is a new traceability tool which provides fish products with a unique bar code and makes it possible to trace back the fish to their original location.