Four products, four grading systems
Dried porcini is graded on flesh and tube-layer colour, expressed as A, B and C. Dried chanterelle is graded on size band and colour, with sand the parameter that most often fails. Dried shiitake is graded on cap diameter and cap thickness, with stem trim policy the line most often left implicit. IQF champignon is graded on cut format and free flow, with blanch adequacy behind the colour.
None of those systems transfers to another species, and applying one specification across the category is how buyers end up with material that meets a document and not a need.
The parameter behind most rejections
Moisture and water activity answer different questions, and the second is the one that predicts spoilage. Because dried mushrooms are heterogeneous, a batch can reach a compliant average with a wet fraction inside it that will mould in store. A conditioning step after drying is what prevents that, and a supplier who does not condition is shipping an average rather than a product.
Wild against cultivated
The two branches fail differently. Cultivated supply fails on residues, on substrate questions at audit and on growing-room contamination. Wild supply fails on availability, on grade drift and on documentation at the border. Cultivated against wild mushrooms sets out both sides, and mushroom grading and moisture control covers the intake routine that catches what the certificate does not.
Where Vorezan sits
Vorezan is an information resource, not a seller, a broker or a certifier. These pages describe how the category is specified and traded. Legal limits are named by the instrument that sets them rather than copied as numbers, because the binding figure is the one in the consolidated text on the day of shipment.