Next Generation Sequencing Technologies for the analysis of a poorly investigated foodstuff: mushroom products authentication by metabarcoding

Multi-species mushroom-based products (MPs) sold in Italy were authenticated by metabarcoding (MB). One degenerated primer pair was projected for the ITS-1 region amplification. The final data were interpreted using positive controls and extraction blanks. Sequences of macrofungi, microfungi and bacteria were detected in 100%, 90.9% and 77.3% of the MPs, respectively. Not edible and toxic macrofungi were also found, although in low sequence amount. The match between species declared on MPs label and species detected by MB was 59.1%. Cases of voluntary species substitution cannot be excluded. Methods to authenticate these products, still poorly investigated, should be further employed, and MB protocol should be standardized to be used in the context of both official control and companies' self-control. Alternative approaches should be considered for canned and frozen MPs, in virtue of the observed DNA fragmentation.