United States 

Department of 

Agriculture 

Agricultural 

Marketing 

Service 

Fruit and 

Vegetable 

Programs 

Fresh Products 

Branch

Mushrooms 

Shipping Point and Market 

Inspection Instructions 

 

 March 2004 

 

 Previously 

 October 1966 
Shipping Point and Market 

Inspection Instructions for 

Mushrooms 

These inspection instructions are specifically developed by the Fresh Products 

Branch to assist officially licensed inspectors in the interpretation and application of the 

U.S. Standards for Grades of Mushrooms, Section 51.3385. 

These instructions do not establish any substantial rule not legally authorized by the 

official grade standards. This publication supersedes any previously issued inspection 

instructions. 

Refer to the General Inspection Instructions for additional information pertaining 

to date, inspection point, carrier, condition of carrier, lading, etc. that is not covered in 

this handbook. Reference to “General Inspection Instructions” in all Fresh Products 

Branch publications refers to any one or all of the following - General Shipping Point 

Inspection Instructions, General Market Inspection Instructions, or Fresh Fruit and 

Vegetable Certificate Writing Handbooks. 

Any portion of these instructions beginning with the section number §51.--- and 

followed by bold print are sections or portions of sections copied directly from the U.S. 

standards. The U.S. Standards for Grades of Mushrooms are printed in the appendix of 

this handbook. All U.S. Standards are available on the Internet under the USDA 

homepage. 

Reformatted January 2003, previously October 1966. 

March 2004 

This publication may be duplicated without authorization from USDA. 
i

Factors noted with (Q) are considered quality only. Factors noted with (C) are 

considered condition at market. Factors noted with (Q or C) may be quality or condition 

depending on the circumstances. Factors not designated do not pertain to either 

category. 

Table of Contents 

GENERAL ............................................................................................................ 1

REPRESENTATIVE SAMPLING ......................................................................... 1

SIZE OF SAMPLE ................................................................................................. 1

NUMBER OF SAMPLES ......................................................................................... 1

TOLERANCES AND APPLICATION OF TOLERANCES ................................... 2

APPLICATION OF TOLERANCES ............................................................................. 4

NOTESHEETS AND CERTIFICATE .................................................................... 5

PRODUCT ........................................................................................................... 5

NUMBER/TYPE OF CONTAINERS ........................................................................... 5

BRANDS/MARKINGS............................................................................................. 6

ORIGIN ............................................................................................................... 6

CONDITION OF PACK ........................................................................................ 6

TEMPERATURE OF PRODUCT ......................................................................... 7

SIZE ..................................................................................................................... 7

DEFECTS (QUALITY AND CONDITION) ............................................................ 8

REPORTING DEFECTS ...................................................................................... 8

DISCOLORATION (C) ............................................................................................ 9

DIRT (Q) ............................................................................................................ 9

FIRMNESS (C) ..................................................................................................... 9

MATURITY (Q)..................................................................................................... 9

OPEN VEILS (C) ................................................................................................ 10

SHAPE (Q) ....................................................................................................... 10

SIMILAR VARIETAL CHARACTERISTICS (Q) ........................................................... 10

SPOTS (C) ........................................................................................................ 10

TRIMMING (Q) ................................................................................................... 11

DECAY (C) ....................................................................................................... 11

APPENDIX I – U.S. GRADE STANDARDS ....................................................... 12

UNITED STATES STANDARDS FOR GRADES OF MUSHROOMS ................................ 12

1

GENERAL 

The U.S. Standards for Grades of Mushrooms apply to types of mushrooms with 

closed veils. Agaricus bisporus more commonly known as “White” mushrooms which 

vary in color from white to light brown, as well as the “Crimini,” which is a brown variety 

of the common white mushroom have closed veils, and may be certified under the U.S. 

grade standards. 

The U.S. Standards for Grades of Mushrooms cannot be applied to varieties with 

open veils and exposed gills. When inspecting open veiled varieties, do not use the 

terms “Grade Defects,” “Injury,” “Damage,” or “Serious Damage.” Furthermore do not 

use terms such as “materially” or “seriously affecting the appearance,” as these terms 

are generally used in the general definitions of damage and serious damage. Describe 

the objectionable factors in terms of color, area affected and depth, etc. 

REPRESENTATIVE SAMPLING 

The importance of obtaining representative samples cannot be over emphasized. 

Accurate certification is possible only if the samples examined are truly representative 

of the entire lot or accessible portion. All portions of a lot or load should receive the 

same attention in sampling regardless of the difficulty involved in reaching all layers or 

parts of a lot or load. Anytime the entire lot requested is not accessible for sampling, 

the inspection and certificate must be restricted to the accessible portion. 

Size of Sample 

The tolerances in the U.S. Standards for Grades of Mushrooms are determined 

on the basis of weight. When inspecting consumer packages, the individual package 

shall be the sample size. When inspecting packages in baskets over two pounds, or 

when loose in flats, or bulk, the sample shall consist of at least one pound. 

To make certain that the sample selected is representative always obtain some 

of the mushrooms from the bottom of each basket sampled. 

Number of Samples 

As a general rule a minimum of 1% of the lot must be examined. For lots of less 

than 300 packages a minimum of 3 samples must be examined. It is the inspector’s 

responsibility to examine additional representative samples when the quality, condition, 

or size in samples is decidedly different to ensure an accurate description of the lot. 
2

TOLERANCES AND APPLICATION OF TOLERANCES 

U.S. No. 1: 

§51.3385 (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. 5 percent for mushrooms in any lot which fail 

to meet the requirements 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 shall be 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. 

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.) 

§51.3386 (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. Ten percent for 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 destination. 25 percent for mushrooms in any lot 

which have open veils. 10 percent for mushrooms in any lot which 

fail to meet the remaining requirements of this grade, but not more 
3

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. 

The shipping point and destination tolerances for grade defects (U.S. No. 1 and 

U.S. No. 2) are as follows: 

Shipping Point:

U.S. No. 1 U.S. No. 2

Off-size 10% 10% 

Open veils - 10% 

Total defects, including 5%* 10% 

Disease, spots or decay 1% 1% 

* The U.S. No. 1 shipping point tolerances do not provide a separate tolerance for open 

veils. Open veils should be included in the 5% for Total Defects. 

En route or Destination:

U.S. No. 1 U.S. No. 2

Off-size 10% 10% 

Open veils 10% 25% 

Total defects, including 5% 10% 

Disease, spots or decay 1% 1% 

Remember that shipping point tolerances apply to certification at U.S ports of entry, port 

of loading for ship stores, shipments to Canada, and Department of Defense purchases. 
4

Application of Tolerances 

§51.3388 Application of tolerances. The contents of individual 

packages in the lot, based on sample inspection, are subject to the 

following limitations: 

(a) For a tolerance of 10 percent or more, individual packages in any 

lot shall have not more than one and one-half times the tolerance 

specified: Provided, That the average for the entire lot is within the 

tolerance specified for the grade. 

(b) For a tolerance of less than 10 percent, individual packages in 

any lot shall have not more than double the tolerance specified, 

except that at least one defective and one off-size specimen may be 

permitted in any package: Provided, That the average for the entire 

lot is within the tolerance specified for the grade. 

The shipping point and destination tolerances and application of tolerances for 

grade defects (U.S. No. 1 and U.S. No. 2) are as follows: 

Shipping Point:

U.S. No. 1 U.S. No. 2

 Lot 

Tolerances 

Container 

Tolerances 

Lot 

Tolerances 

Container 

Tolerances 

Off-size 10% 15% 10% 15% 

Open veils - - 10% 15% 

Total defects, 

including 5%* 10%* 10% 15% 

Disease, spots 

or decay 1% 2% 1% 2% 

The U.S. No. 1 Shipping point tolerances do not provide a separate tolerance for 

open veils. Open veils should be included in the 5% Lot tolerance for Total Defects and 

the 10% Container tolerance for Total Defects. 
5

En route or Destination:

U.S. No. 1 U.S. No. 2

 Lot 

Tolerances 

Container 

Tolerances 

Lot 

Tolerances 

Container 

Tolerances 

Off-size 10% 15% 10% 15% 

Open veils 10% 15% 25% 37.5% 

Total defects, 

including 5% 10% 10% 15% 

Disease, spots 

or decay 1% 2% 1% 2% 

NOTESHEETS AND CERTIFICATE 

Entries on the notesheet and certificate must be kept in a legible and accurate 

manner. It is mandatory that all information which appears on the certificate be 

supported by information on the notesheet. It is the responsibility of the inspector to 

ensure that all information is properly recorded. Notations shall be recorded so that 

anyone familiar with inspection procedures can interpret them and write a certificate. 

Also remember that notesheets and certificates are Prima-facie evidence and must be 

able to withstand legal scrutiny. 

Detailed instructions pertaining to date, inspection point, place of inspection, type 

of carrier, lading, etc., which are not covered by these instructions may be found in the 

General Inspection Instructions. Additional information and instructions may be given 

by your supervisor. 

Product 

The common name, Mushrooms shall be used to describe this commodity in the 

product heading. Type may be reported in conjunction with Mushrooms or may be 

reported in the “Product/Variety” section on the shipping point inspection certificates or 

in the “Lot ID” section on market notesheet and certificate. 

Mushroom type can be “white,” “cream” or “brown.” 

Number/Type of Containers 

The number of containers shall always be reported. In the market and at 

shipping point locations for stationary lot certification, the inspector shall always verify 

the container count provided by the applicant for each lot and report it as the 
6

“inspector’s count.” If the number of containers available for inspection does not match 

the application it is the inspector’s responsibility to confirm that the amount presented 

for inspection constitutes the lot. If an accurate count cannot be determined, the 

inspector may report the count at someone else’s authority. However, the reason for 

doing so must be reported on the notesheet (e.g., numerous pallets with mixed 

product). 

At shipping point locations for "days-run" certification the applicant generally 

provides a manifest for count and it is acceptable to use this for the number of 

containers. 

Mushrooms are usually packed and shipped loose in fiberboard cartons, packed 

in foam or plastic trays or baskets with film covering. 

Brands/Markings 

The brand, variety, size, count, grade, weight, point of origin and other important 

information appearing on the container should be reported on the notesheet in the 

"Brands/Markings" section. Only the brand name and other key markings necessary to 

properly identify the lot for certification should appear in this section on the certificate. 

Origin 

The inspector should not make a positive statement on their own authority, but 

when container markings list the state or country of origin, it should be quoted in the 

appropriate space on the notesheet and the certificate. If origin is not marked, it is the 

inspectors responsibility to make an effort to obtain this information from the applicant. 

This policy is necessary because some firms may use one mark on the same product 

packed in several states. The inspector can certify only to the marks and has no means 

of verifying what state or country the Mushrooms were grown. 

CONDITION OF PACK 

The pack is seldom a problem. However, mushrooms are packed in a variety of 

bulk and consumer packages. The following terms should be used to describe pack: 

Pint type containers with film wrapping: 

Well filled - When the mushrooms are 1/2 to 1 inch above the rim of the cup. 

Fairly well filled - When the pack is not ideal, cups are at least level full. 

Slightly slack - When mushrooms are slightly below the tops of the cups. 

Slack - When mushrooms are decidedly below the top of cups. Report in 

fractions of an inch. 
7

For other containers, including volume filled flats and bulk lidded baskets: 

Very tight or Excessively filled - When mushrooms are too tight for best 

results, usually resulting in bruising. 

Tight or Well filled - When the container is sufficiently filled to prevent 

movement. Mushrooms may be slightly below the top edge of the container. 

Fairly tight or Fairly well filled - When pack is not ideal, but mushrooms are 

sufficiently packed to prevent injury under normal handling conditions. 

Slack or Loose - When mushrooms are decidedly below the top edge of the 

container and or there is sufficient space which would allow considerable 

movement of the mushrooms. When using the term slack, report in fractions of 

an inch. 

TEMPERATURE OF PRODUCT 

Inspectors would not normally determine or report temperatures at shipping 

point. However, due to the importance of the pulp temperature of fresh fruits and 

vegetables when in transit or at destination, it is essential that the inspector accurately 

determine and report the temperature or range in temperatures on each lot. Pulp 

temperature should be reported regardless of the location of the product, whether in the 

carrier, warehouse, or stacked on the platform. Remember to pre-cool the thermometer 

in order to obtain true readings. Report all temperatures to the nearest whole degree. 

A minimum of three temperatures for each lot must be taken and recorded on the 

notesheet. More temperatures must be taken if the lot is abnormally cold, heated, or 

there is a specific request for temperature, and these must be reported in greater detail 

specifying location in lot or load. 

SIZE 

Size is a requirement of the grade for both U.S. No. 1 and U.S. No. 2 grades. 

The only two sizes recognized are “Small to medium” and “Large.” Any other size 

classifications such as “Small,” “Medium,” or “Jumbo” would not be recognized by the 

standard, and must be specified by the applicant. 

When a recognized size classification or a diameter is specified, it must be 

reported in connection with the grade. Lots not meeting this requirement would be 

reported as “Fail to grade U.S. No. 1 or U.S. No. 2 account of offsize.” When size is 

otherwise specified by the applicant, it must be reported in the “remarks” section 

(example: “Size based on 1 inch minimum diameter, and 1-5/8 inches maximum 

diameter, as specified by applicant”). 

Report the range of size and a mostly statement in the “Description of Product” 

section on shipping point inspection certificates, and in the “Other” section on market 
8

certificates. Size columns must be kept on the notesheet to substantiate the size 

reported. 

§51.3385 (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 in diameter; 

(2) Large - over 1-5/8 inches in diameter. 

§51.3397 Diameter. "Diameter" means the greatest dimension of the 

cap measured at right angles to the stem. 

A tolerance of 10% is provided for mushrooms not meeting the specified size. 

See Tolerances and Application of Tolerances. There is no requirement for length of 

stem; however, it may be reported at applicants request. 

§51.3396 Length of stem. "Length of stem" means the greatest 

distance as measured from the point of attachment of the "veils" on 

the stem to the butt. 

DEFECTS (QUALITY AND CONDITION) 

Statements pertaining to freshness, maturity, shape, color, the amount and type 

of defects, and the amount of decay are shown under the appropriate headings. 

Factors noted with (Q) are considered as QUALITY only (Quality, sometimes 

referred to as “permanent” defects) means defects which do not change during 

storage or shipment (shape, scars, etc.). 

Factors noted with (C) shall be reported as CONDITION on market certificates. 

(Condition defects are defects which are subject to change during shipment or 

storage, including but not limited to bruising, discoloration, shriveling and decay.) 

Those factors noted with (Q or C) may be considered as QUALITY or 

CONDITION, depending on the circumstances. 

Reporting Defects

The U.S. Grades for Mushrooms do not provide definitions for serious damage; 

therefore, all defects shall be considered damage only. 
9

Discoloration (C) 

The U.S. grades for mushrooms require mushrooms to be free from damage by 

discoloration. The inspector should keep in mind that the standard describes two types 

of discoloration, (discoloration and spots) each with separate scoring guidelines. Care 

should be taken when scoring discoloration. 

§51.3395 (a) Discoloration when the color of the cap or stem 

materially affects the appearance or marketing quality of the 

mushrooms. 

Scoring Guide: 

When the color of the cap or stem materially affects the appearance or the 

marketing of the mushrooms or when white or cream type mushrooms are darker than 

tan or light brown in color. 

Dirt (Q) 

Although the Mushroom standard does not state that mushrooms are to be clean, 

the standard does provide guidelines for damage by dirt. 

§51.3395 (b) Dirt when any amount is embedded in the cap or stem. 

Scoring Guide: 

Mushrooms shall be scored against all grades when any amount of dirt is 

embedded in the cap or stem. 

Firmness (C) 

Mushrooms that are shriveled, wilted or flabby shall be scored against the total 

tolerance of the grade(s) when readily noticeable. 

Maturity (Q) 

The firmness of mushrooms will vary with size, type and age. However, a 

requirement of maturity is that the veil may be stretched but not broken. Mushrooms 

that are less firm than others is not important provided the veil is not broken and 

mushrooms are not shriveled or wilted. 

§51.3390 Mature. "Mature" means that the mushroom is firm and 

well developed; the veil area may be stretched but not broken. 
10

Open Veils (C) 

The U.S. Grades for mushrooms require mushrooms to be free from open veils. 

§51.3393 Open Veils. “Open Veils” means that the cap has expanded 

to the extent that the protective covering or “veils” joining the 

margin of the cap to the stem have broken and exposed the gills or 

underside of the cap. 

Note: No additional tolerance is provided for open veils in the U.S. No. 1 grade 

at shipping point. (See Tolerances and Application of Tolerances.) 

Shape (Q) 

All grades require that mushrooms be “fairly well shaped.” 

§51.3391 Fairly well shaped. “Fairly well shaped” means that the 

mushroom cap is not flattened, scalloped, indented or otherwise 

deformed to an extent which materially detracts from the appearance 

or marketing quality. 

Scoring Guide: 

Mushrooms that are flattened, scalloped, indented or otherwise deformed shall 

be reported as “Not fairly well shaped” and scored against the total tolerance of the 

grade(s). 

Similar Varietal Characteristics (Q) 

There are white, cream and brown types of mushrooms. It is usually difficult to 

tell the difference between white and cream mushrooms, particularly if the white 

mushrooms have aged a little and the color has turned a little. However, white and 

brown shall not be mixed in the same container. 

§51.3389 Similar varietal characteristics. "Similar varietal 

characteristics" means that the mushrooms are of the same general 

color. For example, white and brown mushrooms shall not be mixed 

in the same container. 

Spots (C) 

The U.S. Grades for mushrooms require mushrooms to be free from spots. 

Spots which occur as pitted or discolored areas which may or may not penetrate below 

the surface. Spots are usually caused by one of the following diseases: Brown spot or 
11

Dry Bubble (Verticillium), Green Mold (Trichodema) and Bacterial Blotch (Pseudomonas 

tolaasi). No attempt to name the disease shall be made. 

§51.3394 Spots. “Spots” means pitted or discolored areas. 

Scoring Guide: 

If any one spot or a combination of spots exceeds an area one-eighth inch in 

diameter the mushroom is scored against all grades. 

Trimming (Q) 

All grades require mushrooms to be well trimmed. 

§51.3392 Well trimmed. “Well trimmed” means that the stems are 

smoothly cut, free from rough fleshy butts, the flared portion of the 

butt is removed and the remaining portion of the stem does not 

exceed the depth of the cap. 

Decay (C) 

All grades for mushrooms are required to be free from decay. Any amount of 

decay shall be scored against the 1% tolerance for mushrooms affected by disease, 

spots or decay. 

Do not report the type of decay on the certificate. However, when in excess of 

the tolerance report the stages of decay as; early, moderate, or advanced, in the 

“Description of Products” section on the shipping point certificates, and in the “Other” 

section on the market certificates. 
12

Appendix I – U.S. Grade Standards 

United States Standards for Grades of Mushrooms1

Effective July 15, 1966 

Grades

51.3385 U.S. No. 1. 

51.3386 U.S. No. 2. 

Unclassified

51.3387 Unclassified. 

Application of 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 fresh mushrooms 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 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

 5 percent for mushrooms in any lot which fail to meet the requirements 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 

 

1

 Compliance with the provisions of these standards shall not excuse failure to comply with the provisions 

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. 
13

one-fifth of this latter amount or 1 percent shall be 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 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 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.3

 Ten percent for 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 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. 

(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 have not been classified in accordance with either of the 

foregoing grades. The term "unclassified" is not a grade within the meaning of these standards but is 

provided as a designation to show that no grade has been applied to the lot. 

Application of Tolerances 

§51.3388 Application of tolerances.

The contents of individual packages in the lot, based on sample inspection, are subject to the following 

limitations: 

(a) For a tolerance of 10 percent or more, individual packages in any lot shall have not more than one and 

one-half times the tolerance specified: Provided, That the average for the entire lot is within the 

tolerance specified for the grade. 

(b) For a tolerance of less than 10 percent, individual packages in any lot shall have not more than double 

the tolerance specified, except that at least one defective and one off-size specimen may be permitted in 

any package: Provided, That the average for the entire lot is within the tolerance specified for the grade. 

Definitions 

§51.3389 Similar varietal characteristics. 

"Similar varietal characteristics" means that the mushrooms are of the same general color. For example, 

white and brown mushrooms shall not be mixed in the same container. 

§51.3390 Mature.

"Mature" means that the mushroom is firm and well developed; the veil area may be stretched but not 

broken. 

§51.3391 Fairly well shaped.

"Fairly well shaped" means that the mushroom cap is not flattened, scalloped, indented or otherwise 

deformed to an extent which materially detracts from the appearance or marketing quality. 

§51.3392 Well trimmed.

"Well trimmed" means that the stems are smoothly cut, free from rough fleshy butts, the flared portion of 

the butt is removed and the remaining portion of the stem does not exceed the depth of the cap. 

 

3

 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. 
14

§51.3393 Open veils. 

"Open veils" means that the cap has expanded to the extent that the protective covering or "veils" joining 

the margin of the cap to the stem have broken and exposed the gills or underside of the cap. 

§51.3394 Spots.

"Spots" means pitted or discolored areas. 

§51.3395 Damage.

"Damage" means any specific defect described in this section; or an equally objectionable variation of any 

one of these defects, any other defect, or any combination of defects which materially detracts from the 

appearance, or the edible or marketing quality of the individual mushroom or of the mushrooms in the lot. 

The following specific defects shall be considered as damage: 

(a) Discoloration when the color of the cap or stem materially affects the appearance or marketing quality 

of the mushrooms. 

(b) Dirt when any amount is embedded in the cap or stem. 

§51.3396 Length of stem.

"Length of stem" means the greatest distance as measured from the point of attachment of the "veils" on 

the stem to the butt.

§51.3397 Diameter.

"Diameter" means the greatest dimension of the cap measured at right angles to the stem. 

Metric Conversion Table

§51.3398 Metric conversion table

Inches Millimeters 

 (mm) 

1/8 equals............ 3.2 

1/4 equals............ 6.4 

3/8 equals............ 9.5 

1/2 equals............ 12.7 

5/8 equals............ 15.9 

3/4 equals............ 19.1 

7/8 equals............ 22.2 

1 equals............... 25.4 

1-1/4 equals.......... 31.8 

1-1/2 equals.......... 38.1 

1-3/4 equals.......... 44.5 

2 equals............... 50.8 

3 equals............... 76.2 

4 equals.............. 101.6