A Rapid and Efficient Loop-mediated Isothermal Amplification (LAMP) Assay for the Authentication of Food Supplements Based on Maitake (Grifola Frondosa)

Grifola frondosa ("Maitake") is an edible fungus with several nutraceutical properties, largely used in traditional medicine. The increased use of Maitake as a food supplements ingredient raised the need of accurate authentication methods since the morphological identification of G. frondosa is not feasible in formulated food supplements. We developed a diagnostic tool based on loop-mediated isothermal AMPlification (LAMP) for the detection of G. frondosa in food supplements. First, a modified CTAB protocol for DNA extraction from food supplements has been set up and it has been shown to be able to isolate amplifiable total genomic material from different types of commercial products. Subsequently, the LAMP assay confirmed high specificity and good analytical sensitivity, allowing to detect up to 0.62 pg of genomic DNA in less than 20 min. Ten related fungal species resulted negative, confirming the specificity of the assay. The presence of Maitake in commercial food supplements was confirmed, except for one, revealing a mislabeling (or a food fraud). This assay proved to be a rapid powerful tool for food authentication purposes and routine inspections at any level of the supply chain of Maitake-based products and it can be used as a model for other quality control assays of fungal food products.