Researchers found 44 samples were mislabelled when comparing the DNA barcode identification of fish products to the official Brazilian list of species and commercial names.
Products with 28 commercial fish names (255 seafood products) confiscated by government officials were sampled from 14 states including imports from eight countries.
Brazilian authorities recently acted to combat smuggling and fraud in shrimp and fish.
Adoption of DNA barcoding
The Ministry of Agriculture, Livestock and Food Supply (MAPA – Ministério da Agricultura, Pecuária e Abastecimento) has adopted DNA barcoding (i.e. analysing about 650 base pairs of the COI mitochondrial gene) as a standardised method for regulation of processed seafood products.
Brazil adopted a list that paired a fish’s common name with a scientific species designation in 2015.
The first state governmental programme that analysed seafood fraud detected 24% of mislabelling (Carvalho et al., 2015). However, they had only 30 samples of commercially important species from fishmongers, supermarkets and restaurants in Florianópolis.
Oceana said mislabeling can be confusion over names or can occur when a vendor knowingly swaps one kind of seafood for a cheaper or less desirable version.
“It is encouraging to hear that the Brazil government has embraced DNA monitoring of its commercial seafood and standardized seafood names, as this study shows,” said Kimberly Warner, a seafood fraud expert and Oceana’s senior scientist.
The findings mirror the global average identified in a 2016 Oceana analysis which found around 20% of 25,000 seafood samples worldwide were incorrectly labelled.
In the Brazil work, DNA sequences were compared to the BOLD database for molecular identification.
DNA barcode sequence lengths ranged from 479 to 692 bp and comparisons with the BOLD System database resulted in matches with a similarity of 90.51% to 100%.
Examples of mislabelled species
The most mislabelled species were: merluza (6), corvina (5), pescada branca (5), surubim/pintado (4), garoupa (3), linguado (3) and pescada amarela (3).
Bacalhau (cod) and salmão (salmon) had the highest numbers of samples analysed (31 and 26), and only one case of mislabelling for cod was found, in which the sample was Molva dypterygia.
“A clear case of economic fraud…was found within a frozen fillet labelled as linguado (flounder) that was substituted with Pangasionodon sp, a species known in Brazil as panga (basa),” said researchers.
“Another clear case of intentional economic fraud was found in two samples labelled as haddock, one smoked fillet and the other carpaccio.
“The species detected were Gadus sp (cod) and Leipocybium flavobrunneum (escolar), but according to Brazilian regulations, only the species Melanogrammus aeglefinus may be legally labelled as haddock in Brazil.”
Seafood products from other countries had only one mislabelled sample, an anchovy imported from Italy and molecularly identified as Engraulis encrasicolus, which according to Brazilian regulations should be labelled as biqueirão.
Companies caught selling mislabelled products were put under a notice of control by DIPOA – Departamento de Inspeção de Produtos de Origem Animal, which required morphological identification of products in stock, documentation check for traceability of fish, and if necessary, more DNA tests to ensure unambiguous taxonomic identification.
The study also found non-compliant labelling considered fraudulent substitutions.
“For instance, in the case of the dourada sample, it was specified on the package as being the species Salminus spp, but instead we detected Brachyplatystoma vaillantii and Brachyplatystoma rousseauxii, whilst the garoupa sample declared as Epinephelys marginatus was substituted with E. morio.
“The merluza sample (hake) indicated the species to be Merluccius hubbsi, but instead was identified using DNA Barcoding as Sphyraena sp, a species that can be sold as barracuda or bicuda according to Brazilian IN 29 standard.
“This is a very clear case of an intentional fraudulent act since Sphyraena sp is morphologically very distinct from Merluccius hubbsi, because they belong to two different fish orders.”
Source: Fisheries Research Volume 191, July 2017, Pages 30–35
“Nationwide Brazilian governmental forensic programme reveals seafood mislabelling trends and rates using DNA barcoding”
Authors: Daniel Cardoso Carvalho, Danusa Guedes, Maria da Gloria Trindade, Regina Melo Sartori Coelho, Paulo Humberto de Lima Araujo