Ingeniero Industrial

United States
Department of
Agriculture
Agricultural
Marketing
Service
Fruit and
Vegetable
Programs

United States Standards
for Grades of
Mushrooms

Fresh
Products
Branch

Effective July 15, 1966
(Reprinted - January 1997)

United States Standards for Grades of Mushrooms1

Grades
51.3385 U.S. No. 1.
51.3386 U.S. No. 2.
Unclassified
51.3387 Unclassified.
Applicationof Tolerances
51.3388 Application of tolerances.
Definitions
51.3389 Similar varietal characteristics.
51.3390 Mature.
51.3391 Fairly well shaped.
51.3392 Well trimmed.
51.3393 Open veils.
51.3394 Spots.
51.3395 Damage.
51.3396 Length of stem.
51.3397 Diameter.
Metric Conversion Table
51.3398 Metric conversion table.
Grades
§51.3385 U.S. No. 1.
"U.S. No. 1" consists of freshmushrooms of similar varietal characteristics which are mature, at
least fairly well shaped, well trimmed, free from open veils, disease, spots, insect injury, and
decay, and from damage by any cause.
(a) Size. Size is specified in terms of diameter and unless otherwise specified meets the
requirements of one of the following size classifications:
(1) Small to medium -- up to 1-5/8 inches indiameter;
(2) Large -- over 1-5/8 inches in diameter.
(b) Tolerances. In order to allow for variations incident to proper grading and handling the
following tolerances, by weight, are provided as specified:
(1) At shipping point.2 5 percent for mushrooms in any lot which fail to meet the requirements
1

Compliance with the provisions of these standards shall not excuse failure to comply with theprovisions of the
Federal Food, Drug and Cosmetic Act, or with applicable State laws and regulations.
2

Shipping point, as used in these standards, means the point of origin of the shipment in the producing area or at
port of loading for ship stores or overseas shipment or, in the case of shipments from outside the continental United
States, the port of entry into the United States.

1of this grade, but not more than one-fifth of this amount or 1 percent shall be allowed for
mushrooms affected by disease, spots, or decay.
(2) En route or at destination. 10 percent for mushrooms in any lot which have open veils. 5
percent for mushrooms in any lot which fail to meet the remaining requirements of this grade,
but not more than one-fifth of this latter amount or 1 percent shallbe allowed for mushrooms
affected by disease, spots, or decay.
(3) For off-size. Ten percent for mushrooms in any lot which fail to meet the specified size
requirements.
§51.3386 U.S. No. 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.
(a) Size. Size is specified in terms ofdiameter and unless otherwise specified meets the
requirements of one of the following size classifications:
(1) Small to medium -- up to 1-5/8 inches in diameter;
(2) Large -- over 1-5/8 inches in diameter.
(b) Tolerances. In order to allow for variations incident to proper grading and handling the
following tolerances, by weight, are provided as specified:
(1) At shipping point.2 Ten percentfor mushrooms in any lot which have open veils. Ten
percent for mushrooms in any lot which fail to meet the remaining requirements of this grade,
but not more than one-tenth of this latter amount or 1 percent shall be allowed for mushrooms
affected by disease, spots, or decay.
(2) En route or at destination. 25 percent for mushrooms in any lot which have open veils. 10
percent for mushroomsin any lot which fail to meet the remaining requirements of this grade,
but not more than one-tenth of this latter amount or 1 percent shall be allowed for mushrooms
affected by disease, spots, or decay.
(3) For off-size. 10 percent for mushrooms in any lot which fail to meet the specified size
requirements.
Unclassified
§51.3387 Unclassified.
"Unclassified" consists of mushrooms which...