A next-generation sequencing approach for the detection of mixed species in canned tuna

Regina Klapper; Amaya Velasco; Maik Döring; Ute Schröder; Carmen G Sotelo; Erik Brinks; Marta Muñoz-Colmenero

doi:10.1016/j.fochx.2023.100560

A next-generation sequencing approach for the detection of mixed species in canned tuna

Food Chem X. 2023 Jan 5:17:100560. doi: 10.1016/j.fochx.2023.100560. eCollection 2023 Mar 30.

Authors

Regina Klapper¹, Amaya Velasco², Maik Döring¹, Ute Schröder³, Carmen G Sotelo², Erik Brinks⁴, Marta Muñoz-Colmenero²

Affiliations

¹ Max Rubner-Institut, Federal Research Institute of Nutrition and Food, National Reference Centre for Authentic Food, E.-C.-Baumann-Straße 20, 95326 Kulmbach, Germany.
² Instituto de Investigaciones Marinas (CSIC), Eduardo Cabello 6, 36208 Vigo, Spain.
³ Max Rubner-Institut, Federal Research Institute of Nutrition and Food, Department of Safety and Quality of Milk and Fish Products, Palmaille 9, 22767 Hamburg, Germany.
⁴ Max Rubner-Institut, Federal Research Institute of Nutrition and Food, Department of Microbiology and Biotechnology, Hermann-Weigmann-Str. 1, 24103 Kiel, Germany.

Abstract

Tuna cans are relevant seafood products for which mixtures of different tuna species are not allowed according to European regulations. In order to support the prevention of food fraud and mislabelling, a next-generation sequencing methodology based on mitochondrial cytochrome b and control region markers has been tested. Analyses of defined mixtures of DNA, fresh tissue and canned tissue revealed a qualitative and, to some extent, semiquantitative identification of tuna species. While the choice of the bioinformatic pipeline had no influence in the results (p = 0.71), quantitative differences occurred depending on the treatment of the sample, marker, species, and mixture (p < 0.01). The results revealed that matrix-specific calibrators or normalization models should also be used in NGS. The method represents an important step towards a semiquantitative method for routine control of this analytically challenging food matrix. Tests of commercial samples uncovered mixed species in some cans, being not in compliance with EU regulations.

Keywords: Amplicon sequencing; Food fraud; NGS; Seafood; Thunnus species identification; Tuna cans.