DIFFERENTIATION OF SEAFOOD
Development and validation of a DNA (meta)-barcoding method for species differentiation in food with focus on seafood
Picture: Kristina Gense
Picture: Kristina Gense
Picture: Kristina Gense
Food scandals in recent times showed that not all products are - as could be expected - unambiguously declared. Authentic food products serve as a base for people who suffer from food allergies or incompatibilities or aim for specific diets (vegan, vegetarian, halal,…) in order to maintain their traditions. A correct declaration is mandatory for traceability of the whole food chain, to embank illegal fisheries and to support protection of endangered species. Moreover, a false declaration leaves the door open for inadequate high prices for low-graded products. Origins may lie in mistranslation or even criminal motifs such as food fraud.
Animal species can be detected by means of protein- or DNA-based methods. Due to lower stability of proteins and higher stability of DNA itself, DNA based methods are applied not only to raw and slightly processed food products but also enable the analysis of highly processed food like convenience food or fermented foods. Numerous real-time PCR assays specific for the respective species are currently available in DNA-based methods; by combining these individual reactions (multiplexing), several animal species can also be detected in a single assay. Existing DNA metabarcoding methods work with relatively long amplicons and with defined group assays (e.g., for mollusks only) that are not applicable to all taxonomic classes.
The challenge is to find a suitable system for the identification of "seafood" (crustaceans and molluscs and products made from them according to Chapter B35 of the Codex Alimentarius Austriacus) that covers a large number of species at the same time, allows the unambiguous identification of individual species in raw and processed state and also has a high sensitivity, i.e., also allows the detection of the smallest portions.
In the DNA-metabarcoding assay developed within the scope of this Workpackage, highly conserved DNA segments (amplicons), which differ in the nucleotide sequence of each animal species and thus serve as a characteristic "barcode" of the respective animal species, are sequenced and assigned to an animal species without any doubt based on a database ("Next Generation Sequencing").
The novelty is that it allows the species of all animal classes that fall into the category of "seafood" according to the Codex Alimentarius Austriacus to be identified and analysed simultaneously in a single assay, in raw and processed state: Crustaceae (crustaceans), Coleoidea (squid), Gastropodae (snails), Veneridae (clams), Pectinidae (scallops), Ostrea (oysters) and Mytili edules (mussels).
The assay developed will greatly facilitate and accelerate the control of seafood authenticity by food laboratories and control offices and bring more transparency and safety to this area, which has been difficult to verify so far.
Lead Researcher:
DI Verena Peterseil
Unit Molecular Microbiology
Österreichische Agentur für Gesundheit und Ernährungssicherheit
verena.peterseil@ages.at
+43 (50) 5553 2203
www.ages.at
