Should we trust the names of fish sold to us? An in-depth analysis of adulteration throughout the Belgian fisheries industry

Onderzoeksoutput: Bijdrage aan congresPoster


As the fisheries industry continues to aggrandise and consumers press to receive reliable and
accurate product information, more rigid regulation of labelling and control mechanisms of
food products throughout the fisheries industry are needed. The removal of certain
deterministic traits such as fins or the head causes a major problem for accurate identification
of species in fish products. In addition, fish in prepared meals or fish soup are impossible to
identify using traditional methods. DNA barcoding forms a solution for these processed food
products and has already shown to be successful at revealing adulteration of several fishes. This
method involves amplifying and sequencing a small biomarker fragment of DNA from the
samples and comparing the sequence to a reference database with sequences of known species.
These databases, however, are prone to mistakes due to a lack of curators and additionally the
species names used in this database are not always compendious. In this study, a reference
database with COI (Cytochrome oxidase 1) and Cytb (Cytochrome b) mitochondrial genes was
created to serve as a reliable platform for barcode sequences of European seafood species. This
database contains voucher specimens collected across various European seas (and rivers) which
are photographed and morphologically identified to species level by taxonomic experts. This
ensures sequences are linked to the correct species. Thus far the database contains 81 COI
sequences and 77 Cytb sequences from 24 fishes spanning 11 families, which are regularly
consumed in Europe or frequently used as adulterants. Phylogenetic trees and the distribution
of intra- and interspecific P-distances show these genes’ strengths as barcoding sequences. COI
displays a clear barcoding gap and indicates that using a threshold of 2 to 5.2% divergence will
give a 100% correct species identification. Cytb displays some overlap between species, but still
indicates that a threshold of 4.5 to 4.6% divergence will give an error rate of 0,18% which is well
within a 95% confidence interval. Most adulteration studies have focused on the end point of
the food chain. Our approach is to assess more precisely where and how adulteration takes
place along the whole food chain. For this, we will thoroughly map out all steps in the fish
processing chain. Once we have a clear overview of the different steps we will sample a selected
number of fishes at various points along the supply chain. Gadus morhua and Solea solea are
consistently among the most preferred fishes for consumption by Belgian consumers and are
consistently among the most landed fish. Both fishes are also expensive, making them prone to
adulteration. In addition, there is a substantial amount of imported fish in Belgium, especially of
round fish, which are suspects to be adulterants of cod. The application of DNA barcoding will
unveil the prevalence of fishery product adulteration in the Belgian market and the factors
influencing adulteration (such as times transferred, type of supplier, distance from ocean, price
or processing type) of fish products in the Belgian market.
Aantal pagina's1
StatusGepubliceerd - 13-mrt-2019
EvenementVLIZ Marine Science Day (2019) - MEC Staf Versluys, Bredene, België
Duur: 13-mrt-201913-mrt-2019


CongresVLIZ Marine Science Day (2019)
Verkorte titelVMSD2019


  • B260-mariene-biologie

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