Autentication of fish species by isoelectric focusing and two dimensional electrophoresis : application to freshwater fish commercially labelled "perch"
Contributo in Atti di convegno
Data di Pubblicazione:
2004
Citazione:
Autentication of fish species by isoelectric focusing and two dimensional electrophoresis : application to freshwater fish commercially labelled "perch" / V. Tepedino, A. Berrini, V. Borromeo, V. Giaccone, C. Secchi - In: Proceedings of the 5. World Congress Foodborne Infections and Intoxication[s.l] : Federal Institute for Risk Assesment, 2004. - pp. 192-192 (( Intervento presentato al 5. convegno World Congress Foodborne Infections and Intoxications tenutosi a Berlin nel 2004.
Abstract:
According the United Nation’s FAO the average consumption of fish per inhabitant is rapidly
increasing, and predicted to multiply 7 fold in the next decade. The growing consumer
demand together with the opening of new international markets have boosted the global
trade of fisheries products and the variety of fish species that regularly arrive on the
worldwide markets. The seafood safety will be therefore a major challenge for veterinary
inspectors. A serious risk for human health is the mislabelling of seafood products. For
example it is indispensable to unambiguously identify species that may contain toxins or can
cause allergic reactions, or during an official block of the import of a particular species due to
sanitary reasons. In addition, difficulties in identification can encourage fraudulent practices
such as replacing species with different commercial values. Morphological criteria are
commonly used for seafood identification, but in doubtful cases or when the fish are sold
without clear morphology (i.e. filleted) biochemical analyses are fundamental to ensure
accuracy (1-2).
In the present paper isoelectric focusing (IEF) and two-dimensional electrophoresis (2-DE)
were applied to identify four fish species commercially sold under the generic label of
“perch”, which arrive on the fish markets already filleted in view of their numerous bones. The
four species are: 1) the European perch (Perca fluviatilis); 2) the Nile perch (Lates niloticus);
3) the European pikeperch (Stizostedion lucioperca); 4) the Sunshine bass (Morone
chrysops x saxatilis). These fish have significantly different commercial values, the European
perch being the most appreciated by consumers and commanding the highest prices.
Hygienical and sanitary problems arise from the treatment of Nile perch, which is filleted in
the country of origin (Egypt and Central Africa countries) and then exported to Europe. Many
cases of sanitary blocks of import of products coming from Africa, occurred in recent years.
Each species showed characteristic IEF pattern and 2-DE map, with differences making for
easy discrimination. The IEF patterns of the water-soluble proteins extracted from the white
muscle of the four species were species-specific, and, when analysed with suitable software
and compared with standard patterns archived in a data-base, permitted a quick and correct
identification. Interestingly, none of the IEF bands was common to the four species. The 2-
DE maps showed numerous spots, distributed mainly in the acidic part of the IPG pH
gradient. Numerous spots are species-specific, although some were similar in the four
species. These similarities allowed to assign some spots to specific proteins, an thus allowed
a first insight into the proteome of these poorly characterized species.
In conclusion, the simple and quick native IEF analysis of the water-soluble proteins
extracted from the white muscle serves to distinguish the four species. Thus, the method
results a suitable tool for the authority whose task is to guarantee quality control in order to
reduce or even avoid mislabelling and frauds. The more sophisticated, expensive and timeconsuming
2-DE, may have major application to deepen the knowledge of fish proteome.
Moreover, the proteomic approach has been recently shown to be suitable to identify makers
of health status of an organism, contamination levels and post-mortem changes (2).
Tipologia IRIS:
03 - Contributo in volume
Elenco autori:
V. Tepedino, A. Berrini, V. Borromeo, V. Giaccone, C. Secchi
Link alla scheda completa:
Titolo del libro:
Proceedings of the 5. World Congress Foodborne Infections and Intoxication