Molecular methods for the differentiation of species used in production of cod-fish can detect commercial frauds

A molecular approach was used to differentiate eight species commonly used in the production of cod-fish. Since visual identification can only be applied easily on whole fish, we used the PCR method to obtain a short fragment of the cytochrome B (cytB) gene that was then analyzed by RFLP, SSCP and DGGE. While RFLP and SSCP resulted in differentiation of only some of the species tested, DGGE was able to produce patterns that made possible the identification of the species considered. The application of molecular methods to the identification of the species in this study was found to be useful, fast and reliable.