ELISA-based detection of mislabeled albacore (Thunnus alalunga) fresh and frozen fish fillets

Abstract

An indirect enzyme-linked immunosorbent assay (ELISA) has been developed for the identification of albacore (Thunnus alalunga) and its differentiation from other lessvalued scombrid species such as yellowfin tuna (Thunnus albacares), bullet tuna (Auxis rochei), atlantic bonito (Sarda sarda), bigeye tuna (Thunnus obesus), little tunny (Euthynnus alleteratus) and skipjack tuna (Katsuwonus pelamis). The assay uses polyclonal antibodies raised in rabbits against soluble muscle protein extract from fresh albacore. These polyclonal antibodies were rendered species-specific by blocking them with the heterologous soluble muscle proteins, allowing discrimination between fresh albacore and the rest of the scombrid species, except for yellowfin tuna. A total of 40 commercial albacore fresh and frozen fillets were analysed, revealing an incorrect labelling in 32.5% of the albacore samples. However, positive samples (67.5%) could be albacore or yellowfin tuna and should require a DNA assay as discriminatory technique.

Overview on Untargeted Methods to Combat Food Frauds: A Focus on Fishery Products

“…Several immunological tests based on enzyme-linked immunosorbent assay (ELISA) tests have been also reported in literature and used to detect mislabeling of fish products [26][27][28]. ELISA may prove to be useful even in heat-sterilized products, although they are ineffective at differentiating loosely related species and require the development of antibodies directed against the specific protein of interest.…”

“…SIMCA (soft independent modeling of class analogy) [136], UNEQ (unequal dispersed classes) [137], and potential functions techniques [138] can be cited among classmodeling methods that have been extensively exploited for the assessment of authenticity or adulteration of several food commodities, including olive oil, honey, alcoholic beverages (wine, beer, and distilled beverages), soft drinks, coffee, milk, cheese, meat, and vegetables (see [135,139] and references cited therein). Application of class-modeling methods to Detection of fish mislabeling [26][27][28] Chemical methods…”

Multiplex PCR Assay for Simultaneous Identification of Five Types of Tuna (Katsuwonus pelamis, Thunnus alalonga, T. albacares, T. obesus and T. thynnus)

“…Protein-based assays for fish species identification have been previously reported, such as isoelectric focusing, isoelectric focusing in immobilized pH gradients, two-dimensional electrophoresis, and enzyme-linked immunosorbent assay [8][9][10][11][12][13][14][15]. However, protein-based analytical methods for species identification are limited because of the proclivity of proteins to denature during heat and high-pressure treatment [16].…”

DNA barcoding of fish species reveals low rate of package mislabeling in Qatar

“…In the past, immunological techniques, e.g., ELISAs, have been used for the identification of certain proteins in seafood products. However, such techniques had limitations including the inability to distinguish among some species because of low specificity (Carrera et al 2014). With DNA barcoding using the cytochrome c oxidase gene (COI) and the establishment of databases on DNA-based taxonomy (Barcode of Life Databases or BOLD) for fishes and other aquatic animals, seafood authentication has been a reality and has been adopted by researchers and regulatory agencies worldwide (e.g., Hanner et al 2011).…”