The problem in identifying species in marine food concerns not only direct product sale to consumers, but also operations performed between providers of raw materials and processed products.

In fishing products that are sold refrigerated or frozen, it is relatively easy to identify the species origin by using morphological characteristics. An alternative, in case of transformed products,is to employ characteristics that remain unaltered during different production or transformation processes (canning, smoking, salting); these characteristics are called biochemical taxonomic characters, among which the sequence of nucleic acids (DNA) is worth noting.

The fish group considered tunny includes organisms of the genera Thunnus, Sarda, Katsuwonus, and Euthynnus, which have different prices in the market depending on the country. Likewise, there is a commercial difference in labeling Thunnus species. Generally, the label "white tuna" implies the product should contain Thunnus alalunga; “light tuna” refers to Thunnus albacares; and “tuna" can contain any Thunnus or similar species. Because it is extremely complicated to identify tuna species sterilized by heat (canned) by means of conventional techniques, the use of analysis techniques based on DNA have been widely supported; in fact it has been demonstrated that the mitochondrial DNA (mDNA) analysis has been successful in species differentiation.

Thus, according to the previous information and based on the needs of the productive sector, the objective of this project is to develop a method based on the  analysis of specific mDNA fragments to differentiate processed tuna species (K. pelamis, “skipjack tuna”; T. albacares, “Yellowfin tuna” and T. obesus, “Big Eye tuna”).