Standardization, quality control, and functional characterization of Tamogi mushroom [Pleurotus citrinopileatus Singer (1943)] filter tea: toward a product internal standard for functional food applications. Part II

The increasing demand for functional beverages derived from medicinal mushrooms necessitates robust standardization frameworks to ensure product quality, safety, and efficacy. This study presents the development and validation of a Product Internal Standard for Tamogi filter tea formulated from Pleurotus citrinopileatus and synergistic medicinal ingredients, including Cordyceps militaris, Trametes versicolor, Ganoderma spp. and Glycyrrhiza glabra. A multi-dimensional quality control approach integrating sensory, physicochemical, microbiological, and bioactive compound analyses was applied. Key parameters, including moisture content, ash values, and β-glucan concentration, were quantified. Analytical techniques, including UV-Vis spectrophotometry and standardized microbiological assays, were applied to evaluate product quality and safety according to national regulatory frameworks. Heavy metal contamination (Pb, Cd, and As) was determined via ICP-MS. Results demonstrated that the developed product meets stringent quality criteria (moisture <8%, β-glucan >20 mg/mL, absence of pathogenic microorganisms, and heavy metals within permissible limits). Notably, the high β-glucan content supports potential immunomodulatory functionality. The proposed TCCS provides a scalable and scientifically grounded model for the standardization and commercialization of mushroom-based functional teas, contributing to value chain development and sustainable utilization of medicinal fungi.