A polymerase chain reaction-restriction fragment length polymorphism method based on the analysis of a 16S rRNA/tRNA(Val) mitochondrial region for species identification of commercial penaeid shrimps (Crustacea: Decapoda: Penaeoidea) of food interest.

A simple PCR-RFLP method has been developed for the identification of 19 penaeid shrimp species of food interest belonging to the superfamily Penaeoidea. Preliminary amplification, sequencing and alignment of a 960 bp fragment of the 16S rRNA/tRNA(Val)/12S rRNA mitochondrial region allowed the design of 16Scru4/16Scru4 primers, constructed on well-conserved mitochondrial sequences of the penaeid shrimp species considered. Such primers afforded the amplification of an internal 515-535 bp region of the 16S rRNA/tRNA(Val) genes that, when subjected to cleavage with AluI, TaqI and HinfI, provided species-specific restriction patterns. Moreover, the proposed method also allowed the definition of different intraspecific restriction types between different populations of Litopenaeus vannamei, Farfantepenaeus notialis, Fenneropenaeus merguiensis, Metapenaeus sp., Melicertus latisulcatus and Pleoticus muelleri of different origins. The method described here was also successfully applied for the identification of penaeid shrimps in complex processed precooked foods, where this type of shellfish is used as an added-value food ingredient. Sequencing analysis provided new information about the genetic relationships among shrimps not only at the levels of species and genus, but also among different populations at intraspecific level. The 16S rRNA/tRNA(Val) fragment considered in this study seems to be accurate for shrimp species identification in raw and processed foodstuffs and for phylogenetic analysis among penaeid shrimp species.