Mushrooms Grades and Standards

Grades of Mushrooms

1. U.S. No. 1 consists of fresh button mushrooms with similar varietal characteristics (except when designated as a mixed or specialty pack), which are mature, firm, fairly well shaped, well trimmed, free from insect injury, disease, and decay, and free from damage by open veils, spots, or any other cause.
2. U.S. No. 2 the requirements for this grade are the same as for U.S. No. 1 except for a greater tolerance for open veils and a larger tolerance for defects.
3. U.S. No. 1 Portabella consists of fresh open mushrooms with similar varietal characteristics (except when designated as a mixed or specialty pack), which are mature, firm, fairly well shaped, well trimmed, free from insect injury, disease, and decay, and free from damage by spots or any other cause.
    

Visual Aids

Visual Aids may be found in the Official Inventory of Inspection Aids (pdf)

• Unofficial Mushroom Visual Aid (pdf)

Detailed Standards, Inspection Instructions & Other Resources:

• U.S. Grade Standards for Mushrooms (pdf)
• Inspection Instructions for Mushrooms (pdf)