Molecular authentication of mushroom products: First survey on the Italian market

For the first time, mushroom products sold on the Italian market were authenticated using DNA barcoding. The analysis was performed on 71 market products (MPs) of different types (canned, dried, frozen, ready-to-cook - dishes) collected in supermarket chains. The ITS complete region was amplified and sequenced. The obtained sequences were then submitted to a BLAST analysis against both an internal dataset developed in a previous study and GenBank for species identification. Issues during amplification and sequencing were especially highlighted for canned products, plausibly due to the processing. The internal dataset was able to support the identification at species level. However, the need to improve it with sequences of commercially relevant species it is essential to increase its identification capability. Cases of suspected mislabeling were observed, with Agaricus bisporus and Bjerkandera adusta respectively found in two products labeled as Boletus edulis and its group. The presence of B. adusta, a not edible plant pathogen, also highlighted a scarce attention in the application of good hygiene and manufacturing practices. Since only 1 or 2 sequence/s were produced from each MP, we cannot exclude that mislabeling rate (2.8%) may be under-estimated. Specific guidelines on sampling strategy should be therefore fixed for mislabeling assessment purposes. Also, the use of alternative DNA based methods, such as metabarcoding, able to identify all the species present in a sample, should be considered.

Automated summary

DNA barcoding was used to authenticate mushroom products sold on the Italian market for the first time. A total of 71 market products of different types were collected and analyzed. Issues with amplification and sequencing were observed, especially in canned products. Mislabeling cases were found, suggesting a need for better identification and manufacturing practices. Only 1 or 2 sequences were obtained from each product, so the mislabeling rate may be under-estimated. Specific guidelines and alternative DNA-based methods should be considered for accurate species identification.