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United States Standards

for Grades of Frozen 

Onions

Effective September 21, 2017
This is the first issue of the United States Standards for Grades of Frozen Onions

(82 FR 39658).

Voluntary U.S. grade standards are issued under the authority of the Agricultural 

Marketing Act of 1946, which provides for the development of official U.S. grades to 

designate different levels of quality. These grade standards are available for use by 

producers, suppliers, buyers, and consumers. As in the case of other standards for 

grades of fresh and processed fruits, vegetables, and specialty crops these 

standards are designed to facilitate orderly marketing by providing a convenient 

basis for buying and selling, for establishing quality control programs, and for 

determining loan values. 

The U.S. grade standards and inspection instructions for all fresh and processed fruits,

vegetables, and specialty crops are available on the internet and upon request at the 

address below. These documents provide detailed interpretations of the grade standards 

and provide step-by-step procedures for grading the product. 

Grade standards are issued by the U.S. Department of Agriculture (USDA) after careful 

consideration of all data and views submitted during rulemaking. The Department 

welcomes suggestions for improving the standards in future revisions. Comments may be 

submitted to, and copies of standards and inspection instructions obtained from: 

Director, Specialty Crops Inspection Division

Specialty Crops Program,

USDA, Agricultural Marketing Service

1400 Independence Avenue, SW, STOP 0240 

Washington, D.C. 20250

__________________________________________________________________________

Authority: 7 U.S.C. 1621-1627. 

Note: 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.

Non-Discrimination Policy: In accordance with Federal civil rights law and U.S. Department of Agriculture (USDA) civil rights 

regulations and policies, the USDA, its Agencies, offices, and employees, and institutions participating in or administering USDA 

programs are prohibited from discriminating based on race, color, national origin, religion, sex, gender identity (including gender 

expression), sexual orientation, disability, age, marital status, family/parental status, income derived from a public assistance program, 

political beliefs, or reprisal or retaliation for prior civil rights activity, in any program or activity conducted or funded by USDA (not all 

bases apply to all programs). Remedies and complaint filing deadlines vary by program or incident.

Persons with disabilities who require alternative means of communication for program information (e.g., Braille, large print, audiotape, 

American Sign Language, etc.) should contact the responsible Agency or USDA's TARGET Center at (202) 720-2600 (voice and TTY) 

or contact USDA through the Federal Relay Service at (800) 877-8339. Additionally, program information may be made available in 

languages other than English.

To file a program discrimination complaint, complete the USDA Program Discrimination Complaint Form, AD-3027, found online at How 

to File a Program Discrimination Complaint and at any USDA office or write a letter addressed to USDA and provide in the letter all of 

the information requested in the form. To request a copy of the complaint form, call (866) 632-9992. Submit your completed form or 

letter to USDA by: (1) mail: U.S. Department of Agriculture, Office of the Assistant Secretary for Civil Rights, 1400 Independence 

Avenue, SW, Washington, D.C. 20250-9410; (2) fax: (202) 690-7442; or (3) email: program.intake@usda.gov.

USDA is an equal opportunity provider, employer, and lender.
United States Standards for Grades of Frozen Onions (September 21, 2017)

1

United States Standards for Grades of Frozen Onions

Section Page No.

§52.4072 Product description...................................................................................... 2

§52.4073 Styles........................................................................................................... 2

§52.4074 Requirements for style................................................................................. 2

§52.4075 Definitions of terms...................................................................................... 3

§52.4076 Grades......................................................................................................... 6

§52.4077 Factors of quality. ........................................................................................ 7

§52.4078 Requirements for classified quality factors and defects............................... 7

§52.4079 Sample size............................................................................................... 10

§52.4080 Acceptance criteria. ................................................................................... 10
United States Standards for Grades of Frozen Onions (September 21, 2017)

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§52.4072 Product description.

Frozen onions are the individually quick frozen product prepared from fresh, clean, 

sound, firm bulbs of the Grano, Sweet Spanish type, or other common commercial 

varieties of (Allium cepa) that have been properly prepared, washed, blanched or 

unblanched, and then frozen in accordance with good commercial practice and 

maintained at temperatures necessary to preserve the product.

§52.4073 Styles.

(a) Whole means whole stemmed, peeled bulbs of the sizes listed below:

(1) Type I. 7/8 inch (22mm) to 1-7/8 inches (48 mm) in diameter at the

greatest dimension of the onion at right angles to a line running from stem 

to root.

(2) Type II (Pearl). 3/8 inch (10 mm) to 7/8 inch (22mm) in diameter in the

greatest dimension of the onion at right angles to a line running from stem 

to root.

(b) Strips means stemmed, peeled bulbs that have been cut lengthwise into narrow 

pieces ranging from 3/4 inch (19 mm) to 2 inches (51 mm) in length. The width 

may vary from 1/4 inch (6 mm) to 3/4 inch (19 mm).

(c) Diced means peeled bulbs which have been cut into approximately square 

pieces with a designated width ranging from 1/4 inch (6 mm) to 1 inch (25 mm) in 

width as determined by the width of the unit in the greatest cut dimension.

(d) Other means any style designated as other, by style, description of size, shape, 

or other characteristic that differentiates it from the styles listed above.

§52.4074 Requirements for style.

(a) Whole style.

(1) Type I. The units are well shaped. By count, approximately 10 percent of 

the units (lot average) may be less than 7/8 inch (22 mm); 5 percent may 

be greater than 1-7/8 inches (48 mm) at the widest portion of the unit.

(2) Type II (Pearl). The units are well shaped. By count, approximately 10 

percent of the units (lot average) may be less than 3/8 inch (10 mm); 5 

percent may be greater than 7/8 inch (22 mm) in the greatest portion of 

the unit.

(b) Strips style. A maximum of 25 percent of units, by weight, may be less than the

minimum style requirement of 3/4 inch (19 mm) in length. 
United States Standards for Grades of Frozen Onions (September 21, 2017)

3

(c) Diced style. The units that are practically uniform in size. Less than 30 percent 

of the units, by weight, are noticeably smaller than one-half the area of an 

average sized unit (or the designated size). Less than 30 percent of all units are 

large or irregularly shaped units greater than 1-1/2 times the area of an average 

sized unit (or the designated size).

(d) Other. Units do not fall into any of the styles listed above, are reasonably 

uniform in size and shape, and overall appearance is not materially affected by 

other shapes and sizes.

§52.4075 Definitions of terms.

(a) Acceptable quality level (AQL) means the maximum percent of defective units 

or maximum number of defects per hundred units of product that, for the purpose 

of acceptance sampling, can be considered satisfactory as a process average.

(b) Appearance.

(1) Good appearance means that the product is practically free flowing, 

bright, and with practically uniform units. Markedly variable units, small 

specks, or other factors, do not significantly affect the overall appearance 

or edibility of frozen onions.

(2) Reasonably good appearance means that the product is reasonably free 

flowing, reasonably bright, and has reasonably uniform units. The overall 

appearance or edibility of the frozen onions is slightly but not seriously 

affected by markedly variable units, small specks, or other factors.

(3) Poor appearance means that the product fails to meet the requirements 

of reasonably good appearance.

(c) Blemished. A unit that is affected or damaged by pathological injury, insect 

injury, or any other injury that affects the overall appearance or eating quality of 

the unit. 

(1) Minor blemish. A unit with tan to brown blemish(es) that, in the 

aggregate, are larger than the area of a circle 1/8 inch (3 mm) in diameter 

but smaller than 1/4 inch (6 mm) in diameter.

(2) Major blemish. A unit with tan to dark blemish(es) that, in the aggregate, 

are larger than the area of a circle 1/4 inch (6 mm) in diameter.

(3) Total blemish. The total of the major and minor blemishes.

(d) Character refers to the firmness and texture of the individual onion unit and the 

lack of tough, soft, or mushy units.
United States Standards for Grades of Frozen Onions (September 21, 2017)

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(1) Good character. The onions are uniformly firm and tender, and 

practically free of soft and spongy units.

(2) Reasonably good character. The onions are reasonably firm and 

tender, and are not soft or spongy.

(3) Poor character. The product fails to meet the requirements of reasonably 

good character.

(e) Color refers to the predominant and characteristic color of the exterior surface of 

the frozen onions.

(1) Good color. The frozen onions have a good characteristic bright color 

typical of the variety. 

(2) Reasonably good color. The frozen onions have a reasonably good 

color typical of the variety. The units individually or collectively may vary 

slightly from bright to slightly dull. 

(3) Poor color. The units fail to meet the requirements of reasonably good 

color.

(f) Core material is the portion of the onion bulb that is part of the internal or 

external onion flesh. This material should not be discolored, excessively tough, 

fibrous, soft, or mushy. Core material may also include sprouts, seed stems, root 

crown, and root material.

(1) Whole style:

(i) Minor core material is a unit that is 3/8 inch (10mm) or less in 

diameter or length, whichever is applicable. Each unit is the 

equivalent of one minor defect.

(ii) Major core material is a unit that is more than 3/8 inch (10mm) in 

diameter or length, whichever is applicable. Each unit is the 

equivalent of one major defect.

(iii) Total core material is total of the major and minor core material.

(2) Strips, diced, and other styles:

(i) Minor core material is 1/2 square inch (3.2 square centimeters) or 

less. Each unit is the equivalent of one minor defect.

(ii) Major core material exceeds 1/2 square inch (3.2 square 

centimeters). Each unit is the equivalent of one major defect.
United States Standards for Grades of Frozen Onions (September 21, 2017)

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(iii) Total core material is total of the major and minor core material.

(g) Dark green units are units with dark green stripes across 50 percent or more of 

the onion unit. One unit is equivalent to one defect.

(h) Defect is the deviation of a unit(s) from a specified quality characteristic 

requirement.

(i) Extraneous vegetable material (EVM) is any plant material of onions or other 

harmless plants including, but not limited to, the leaves or roots. Each equivalent 

of EVM of 1 inch in length is considered one defect.

(j) Grit or dirt is any particle of earthy material.

(k) Mechanical damage (in whole style only) means that the appearance of the unit 

is affected by gouging, or the unit is crushed or broken to the extent that the 

appearance is materially affected.

(l) Normal flavor and odor means that the frozen onions, before and after cooking, 

have a flavor and odor that is normal and typical for the variety and is free from

objectionable flavors and odors.

(m) Peel is the thin outer skin of the bulb. Peel is usually creamy white to brown in 

color, tough, and tissue-like. Each equivalent of peel that is 1/2 square inch (3.2 

square centimeters) is considered one defect.

(n) Root crown is the tough fibrous material on the bottom portion of the onion 

where the roots attach to the bulb. Root crown is scored as core material.

(o) Sample size is the amount of product specified for use in grading. For varietal 

characteristics, color, flavor and odor, and appearance, the sample size is the 

entire container. For blemishes, character, specified defects, and mechanical 

damage, the sample size is 50 units by count for whole style, and 450 grams by 

weight for strips, diced, and other styles.

The appropriate sample size may be:

(1) The entire contents of a container;

(2) A portion of the contents of a container; or

(3) A combination of the contents of two or more containers.

(p) Sprouts and seed stems are the internal material that protrudes from the top or 

neck of the onion. Scoreable sprouts and seed stems may be tough, fibrous, or 

leathery, and may be white, tan to brown, or green in color. Sprouts and seed 

stems are scored as core material.
United States Standards for Grades of Frozen Onions (September 21, 2017)

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(q) Tolerance (TOL) is the percentage of defective units allowed for each quality 

factor for a specific sample size.

(r) Unit is a whole peeled bulb, immature bulb, individual piece, or portion of frozen 

onions.

§52.4076 Grades.

(a) U.S. Grade A is the quality of frozen onions that meet the following 

requirements:

(1) Similar varietal characteristics except color, when designated as specialty 

or mixed pack;

(2) Has a normal flavor and odor;

(3) Has good color; 

(4) Has a good appearance;

(5) Has no grit or dirt present that affects the appearance or edibility of the 

product; and

(6) Is within the limits for defects as specified in Tables I and II of this subpart 

as applicable for the styles in §52.4078.

(b) U.S. Grade B is the quality of frozen onions that meet the following 

requirements:

(1) Similar varietal characteristics except color, when designated as specialty 

or mixed pack;

(2) Has a normal flavor and odor;

(3) Has a reasonably good color;

(4) Has a reasonably good appearance; 

(5) Has no grit or dirt present that affects the appearance or edibility of the 

product; and

(6) Is within the limits for defects as specified in Tables I and II of this subpart 

as applicable for the styles in §52.4078.

(c) Substandard is the quality of frozen onions that fail to meet the requirements of 

U.S. Grade B.
United States Standards for Grades of Frozen Onions (September 21, 2017)

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§52.4077 Factors of quality.

The grade of frozen onions is based on requirements for the following factors:

(a) Prerequisite quality factors.

(1) Varietal characteristics, except color when designated as specialty or 

mixed pack; 

(2) Color;

(3) Flavor and odor;

(4) Appearance; and

(5) Absence of grit or dirt.

(b) Classified quality factors.

(1) Dark green units;

(2) Poor colored units;

(3) Major blemishes;

(4) Total blemishes (major + minor);

(5) Mechanical Damage (in Whole style only);

(6) Major Core Material

(7) Total Core Material (major + minor);

(8) Peel;

(9) Character; and

(10) EVM.

§52.4078 Requirements for classified quality factors and defects.

(a) Sample size is defined in §52.4075 Definition of Terms.

(b) Acceptance criteria for specified defects are listed in Tables I and II that follow.
United States Standards for Grades of Frozen Onions (September 21, 2017)

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TABLE I

Acceptance Numbers for Specified Defects, Whole Style Frozen Onion

GRADE A (50 Plan)

GRADE B (50 Plan)

 1 Unofficial Samples

2 AQL calculated from tolerance (TOL) at 650 units

Sample Units X Sample Unit Size 1 x 50 6 x 50 13 x 50 21 x 50 29 x 50

Units of Product 50 1 300 650 1050 1450

DEFECTS TOL AQL2 ACCEPTANCE NUMBERS

Dark Green Units 1 0.612 1 4 7 10 14

Poor Color Units 5 3.8 4 17 33 50 67

Major Blemish 2 1.3 2 7 13 20 26

Total Blemish (Major + Minor) 5 3.8 4 17 33 50 67

Mechanical Damage 2 1.3 2 7 13 20 26

Major Core Material 1 0.612 1 4 7 10 14

Total Core Material (Major + Minor) 2 1.3 2 7 13 20 26

Peel 2 1.3 2 7 13 20 26

Character “Reasonably Good” 2 1.3 2 7 13 20 26

Character “Poor” 1 0.612 1 4 7 10 14

EVM 1 0.612 1 4 7 10 14

Sample Units X Sample Unit Size 1 x 50 6 x 50 13 x 50 21 x 50 29 x 50

Units of Product 50 1 300 650 1050 1450

DEFECTS TOL AQL2 ACCEPTANCE NUMBERS

Dark Green Units 2 1.3 2 7 13 20 26

Poor Color Units 8 6.4 6 26 52 80 108

Major Blemish 3 2.9 3 13 26 39 53

Total Blemish (major + minor) 8 6.4 6 26 52 80 108

Mechanical Damage 3 2.9 3 13 26 39 53

Major Core Material 2 1.3 2 7 13 20 26

Total Core Material (major + minor) 3 2.9 3 13 26 39 53

Peel 3 2.9 3 13 26 39 53

Character “Poor” 2 1.3 2 7 13 20 26

EVM 2 1.3 2 7 13 20 26
United States Standards for Grades of Frozen Onions (September 21, 2017)

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TABLE II

Acceptance Numbers for Specified Defects, Strips, Diced or Other Styles Frozen Onion 

GRADE A (450 Gram Plan)

 1 Unofficial Sample

2 AQL calculated from tolerance (TOL) at 5850 units

Sample Units X Sample Unit Size 1 x 450 6 x 450 13 x 450 21 x 450 29 x 450

Total Weight of Product (in grams) 450 1 2700 5850 9450 13050

DEFECTS TOL AQL2 ACCEPTANCE NUMBERS

Dark Green Units 0.11 0.056 1 3 6 9 12

Poor Color Units 0.88 0.696 6 26 51 79 106

Major Blemish 0.22 0.144 2 7 13 19 26

Total Blemish (major + minor) 0.88 0.696 6 26 51 79 106

Major Core Material 0.11 0.056 1 3 6 9 12

Total Core Material (major + minor) 0.44 0.325 3 13 26 40 53

Peel 0.22 0.144 2 7 13 19 26

Character “Reasonably Good” 1.0 0.9 7 32 64 100 135

Character “Poor” 0.5 0.4 4 16 31 48 64

EVM 0.11 0.056 1 3 6 9 12

GRADE B (450 Gram Plan)

Sample Units X Sample Unit Size 1 x 450 6 x 450 13 x 450 21 x 450 29 x 450

Total Weight of Product ( in grams) 450 1 2700 5850 9450 13050

DEFECTS TOL AQL 2 ACCEPTANCE NUMBERS

Dark Green Units 0.22 0.144 2 7 13 19 26

Poor Color Units 2.0 1.72 12 57 117 183 249

Major Blemish 0.67 1.72 5 20 39 60 81

Total Blemish (major + minor) 2.0 1.72 12 57 117 183 249

Major Core Material 0.22 0.144 2 7 13 19 26

Total Core Material (major + minor) 0.88 0.696 6 26 51 79 106

Peel 0.22 0.144 2 7 13 19 26

Character “Poor” 4.0 3.6 23 113 234 370 506

EVM 0.22 0.144 2 7 13 19 26
United States Standards for Grades of Frozen Onions (September 21, 2017)

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§52.4079 Sample size.

The sample size used to determine whether the requirements of these standards are 

met is specified in the sampling plans and procedures in the Regulations Governing 

Inspection and Certification of Processed Fruits and Vegetables, Processed Products 

Thereof, and Certain Other Processed Products (7 CFR 52.1 through 52.83). 

§52.4080 Acceptance criteria.

(a) Style. A lot of frozen onions is considered as meeting the requirements for style 

if the requirements in §52.4074, as applicable, are not exceeded.

(b) Lot inspection. A lot of frozen onions is considered as meeting the 

requirements for quality if:

(1) The prerequisite requirements specified in §52.4077 are met; and 

(2) The Acceptable Quality Levels in Tables I or II of §52.4078 as applicable, 

are not exceeded.

(c) Single sample unit. Each unofficial sample unit submitted for quality evaluation 

will be treated individually and is considered as meeting the requirements for 

quality if: 

(1) The prerequisite requirements specified in §52.4077 are met; and 

(2) The Acceptable Quality Levels in Tables I or II of §52.4078 are not 

exceeded.