Mushroom quality defects are deviations from grade standards including open veils, discolouration, bruising, elongated stems, water spotting and pest damage, which determine whether a lot is accepted for premium use, processing or rejection.
In trade practice
QA teams assess defects against tolerances defined in the purchase specification or applicable grading standard, recording findings on an inspection report that accompanies the lot. Discolouration and bruising are the most frequently disputed defects in dried and frozen mushroom shipments, often arising from delayed cooling or rough handling post-harvest. Buyers should require photographic evidence and retain a sealed reference sample to support any quality claim. The questions page on frozen vegetable defects provides a useful cross-reference for tolerance language.
In a specification
Specifications state maximum permitted defect percentages by category, such as discoloured pieces or open-veil specimens, expressed as a proportion of sample weight or count.