A validated DNA metabarcoding approach for routine authentication of processed bivalves.

Area of Science:

• Food Science
• Molecular Biology
• Marine Biology

Background:

• Species mislabeling in commercial bivalves is a significant issue for food authenticity.
• Broad taxonomic coverage is crucial for effective, untargeted screening of diverse bivalve species.

Purpose of the Study:

• To develop and validate a DNA metabarcoding approach for broad taxonomic screening of bivalves.
• To assess the method's efficacy in detecting species substitution and adulteration in commercial bivalve products.

Main Methods:

• Developed and validated DNA metabarcoding using two PCR assays (singleplex and duplex) targeting mitochondrial 16S rDNA fragments.
• Applied the method to reference samples, model food samples, DNA mixtures, and commercial food products.

Main Results:

• Successfully identified taxa at species or genus level in reference and model food samples.
• Detected individual species at low concentrations (0.008-0.014% w/w) and identified most components in DNA mixtures.
• Found 29% of 70 commercial bivalve products were mislabeled, with scallops most affected.

Conclusions:

• The DNA metabarcoding method is highly effective for detecting species substitution and adulteration in bivalves.
• This validated approach is suitable for routine food authentication and supports regulatory monitoring strategies.
• This represents the first DNA metabarcoding method with broad taxonomic coverage for bivalves.