A rapid methodology for screening hake species (Merluccius spp.) by single-stranded conformation polymorphism analysis.

An accurate screening method for hake species identification based in single-stranded conformation polymorphism analysis is presented. The differentiation of 11 species of the Merluccius genus and another five species of the Gadiformes order was studied. For this purpose, two fragments of the cytochrome b gene were sequenced; the first is the 5'-end, a fragment of 465 bp (Kocher fragment), and the second is the 3'-end of the cytochrome b, a 588 bp fragment (SB fragment). These two fragments were amplified, denatured, and submitted to native nondenaturing polyacrylamide gel electrophoresis. Results show that with this technique and both fragments, all of the species studied can be unequivocally identified. The validation of the methodology was carried out with 24 commercial hake products showing good performance of the technique for species identification in commercial products. Results show that all species were identified. This technique has advantages over other published methods, because only one polymerase chain reaction step is needed, saving time and money, and it decreases the time needed for hake species identification in food products, making it especially suitable as a screening methodology when a high number of samples should be analyzed in routine examinations.