Development and validation of a SYBR-Green I Real-Time PCR test to detect Mytilus species in foods

The incidence of allergy to seafood, and in particular to molluscs is second only to that of nuts. To protect consumers, the regulators of food products insist on identifying molluscs as allergens. The aim was to develop quantitative assay for the presence Mytilus species in processed food products. The chosen platform was real-time PCR (qPCR) targeting either the gene encoding mitochondrial cytochrome C oxidase I or the nuclear gene encoding β-actin. Recombinant plasmids containing each of target regions were used as a reference for quantification purposes. The assay was positive when the template comprised ten copies of the reference plasmid or three genome equivalents of Mytilus DNA. Spiked food samples containing 50-500 µg g-1 of M. chilensis were analysed both by qPCR and by ELISA. The former assay gave a positive outcome over the full range, whereas the latter was sensitive down to a concentration of 125 µg g-1.