A new real-time PCR method for rapid and specific detection of ling (Molva molva)

- A new, rapid and specific RT-PCR assay for the detection of ling was designed.
- New method performed similarly to Forensically Informative Nucleotide DNA Sequencing (FINS).
- The assay was successfully validated with 31 commercial samples.
- 19.4% of commercial samples tested were found to be mislabelled.

Seafood fraud - often involving substitution of one species by another - has attracted much attention as it is prevalent worldwide. Whilst DNA analysis has helped to combat this type of fraud some of the methods currently in use are time-consuming and require sophisticated equipment or highly-trained personnel. This work describes the development of a new, real-time PCR TaqMan assay for the detection of ling (Molva molva) in seafood products. For this purpose, specific primers and a minor groove binding (MGB) TaqMan probe were designed to amplify the 81 bp region on the cyt b gene. Efficiency, specificity and cross-reactivity assays showed statistically significant differences between the average Ct value obtained for Molva molva DNA (19.45 ± 0.65) and the average Ct for non-target species DNA (38.3 ± 2.8), even with closely related species such as Molva dypterygia (34.9 ± 0.09). The proposed methodology has been validated with 31 commercial samples.