Methodological evaluation of DNA-based molecular keys to identify categories of mislabelling in commercial products from genus Merluccius spp

Food Chem. 2018 Jan 15;239:640-648. doi: 10.1016/j.foodchem.2017.06.138. Epub 2017 Jun 27.

Abstract

The large variety of fish formats which are globally commercialized supports use of meta-evaluation studies to test discrimination power among molecular keys available for traceability of highly-degraded and/or chemically-modified DNA material. This paper shows that a combination of DNA identification methods validated for genus Merluccius allows 100% species assignment in hake products and offers higher diagnostic power (97% on products) than individual methods, i.e. Hake-ITS1-RFLP (89%) or Hake-Cytochrome b-RFLP (83%). A global 31% product mislabelling involved 15% of products affected by internal species substitution, as the main cause of mislabelling in ultrafrozen products, and another 16% affected by external species substitution with non-hake species, as the cause of mislabelling in processed and cooked hake-based products. The combination of both DNA keys minimizes the tool-associated rate of diagnostic failure, allowing decoupling of mislabelling categories and maximizing the quantitative adscription of products to species on any kind of hake-based products.

Keywords: Commercial mislabelling; Commercial traceability; Cytochrome b-RFLP; Hake ITS1-RFLP; Hakes; Merluccius spp.; Phylodiagnosis; Species authentication.

MeSH terms

  • Animals
  • Cytochromes b
  • DNA
  • Gadiformes*
  • Polymerase Chain Reaction
  • Polymorphism, Restriction Fragment Length

Substances

  • DNA
  • Cytochromes b