A model to develop biological probes from microflora to assure traceability of tilapia

The bacterial community of Suranaree University of Technology (SUT) tilapia was studied with the aim to develop a model for traceable biological markers. Five fish per time were collected from SUT farm and other sources. Total viable counts (TVC) of bacteria from SUT farm were quite similar in all seasons. Seventy three percent of the bacteria were Gram-negative. Total DNA extracted from the fish gills and intestines were used as template to amplify bacterial 16S rDNA V3 region using GC clamp primer to identify specific bacteria of fish origin by PCR-DGGE technique. The results showed 3 DNA bands on DGGE gel that were specific to only bacterial DNA of SUT tilapia when compared to the other sources. The 3 DNA bands were sequenced and identified as uncultured bacteria of different species. Primers were designed from the 3 specific sequences and used to amplify DNA samples from four sources and some pure cultured bacteria. The results indicated that, only one primer pair can amplify DNA samples from SUT farm but not other samples. This primer pair can be used to identify and trace samples from SUT farm. This method can be used as a model to develop bacterial primer specific location for other food products.