Characterisation of a fungus reference material, and a guide for use

Area of Science:

• Environmental Science
• Food Science
• Analytical Chemistry

Background:

• Accurate quantification of metals in edible fungi is crucial for food safety and environmental monitoring.
• Existing reference materials may not adequately represent the complexity of metal distribution in wild edible mushrooms.
• The need for a reliable standard for metal determination in common edible fungi like Cantharellus tubaeformis.

Purpose of the Study:

• To produce and certify a reference material of Cantharellus tubaeformis for metal analysis.
• To validate the accuracy and homogeneity of the reference material for key metals (Pb, Cd, Zn, Cu, Mn, Cr, Ni, Co, Fe).
• To propose a more user-friendly method for presenting certification results.

Main Methods:

• Drying, homogenization, and sieving of Cantharellus tubaeformis using non-contaminating equipment.
• Thorough mixing and bottling in polythene containers.
• Homogeneity testing via multiple analyses; metal determination using at least two analytical methods by ten participating laboratories.

Main Results:

• Satisfactory homogeneity was confirmed for the reference material.
• Certified metal levels showed good agreement with fresh C. tubaeformis, indicating no contamination during production.
• The 95% confidence interval for the true mean was found to be of limited practical value for users.

Conclusions:

• The produced Cantharellus tubaeformis reference material is suitable for metal determination.
• A user-oriented presentation of results using 95/95% tolerance intervals (based on within- and between-laboratory standard deviations) is recommended.
• These tolerance intervals provide practical guidance for acceptable user results and future measurements.