United States

Department of

Agriculture

Agricultural

Marketing

Service

Fruit and

Vegetable

Programs

Processed

Products

Branch

DRAFT

May 2011

 Effective XX,XX,XXXX 

 Draft

 

United States 

Standards

for Grades of

Frozen Onions
This is the first issue of the United States Standards for Grades of Frozen Onions, to 

published in the FEDERAL REGISTER of XXXXXXXX to become effective XX-XXXXXX

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 processed fruits and vegetables, 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 standards also serve as a basis for the inspection and grading of commodities 

by the Federal inspection service, the only activity authorized to approve the 

designation of U.S. grades as referenced in the standards, as provided under the 

Agricultural Marketing Act of 1946. This service, available as on-line (in-plant) or lot 

inspection and grading of all processed fruit and vegetable products, is offered to 

interested parties, upon application, on a fee-for-service basis. The verification of 

some specific recommendations, requirements, or tolerances contained in the 

standards can be accomplished only by the use of on-line inspection procedures. In 

all instances, a grade can be assigned based on final product factors or 

characteristics.

In addition to the U.S. grade standards, grading manuals or instructions for 

inspection of several processed fruits and vegetables are available upon request for 

a nominal fee. These manuals or instructions contain detailed interpretations of the 

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

Grade standards are issues by the Department after careful consideration of all data 

and views submitted, and the Department welcomes suggestions which might aid in 

improving the standards in future revisions. Comments may be submitted to, and 

copies of standards and grading manuals obtained from:

Chief, Processed Products Branch

Fruit and Vegetable Programs, AMS

U.S. Department of Agriculture

1400 Independence Ave., SW

STOP 0247

Washington, D.C. 20250-0247
United States Standards for Grades of Frozen Onions

_______ ________ _________ __________

Effective Month XX,XXXX

Section Page No. 

'52.4072 Product description. ............................................................................ 1

'52.4073 Styles. .................................................................................................. 1

'52.4074 Requirements for style. ....................................................................... 1

'52.4075 Definitions of terms. ............................................................................. 2

'52.4076 Grades. ............................................................................................... 5

'52.4077 Factors of quality................................................................................. 6

'52.4078 Requirements for classified quality factors.......................................... 7

'52.4079 Sample size. ..................................................................................... 12

'52.4080 Acceptance criteria. ........................................................................... 12

Authority: Agricultural Marketing Act of 1946, Sects. 203, 205, 60 Stat. 1087, 

as amended, 1090, as amended (7 U.S.C. 1622, 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.
1

§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, Allium cepa, which have been properly 

prepared, washed, blanched or unblanched then frozen in accordance with 

good commercial practice and maintained at temperatures necessary for 

the preservation of the product.

§52.4073 Styles.

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

below:

(1) Type I- 7/8 inches (20mm) to 1-7/8 inch (48 mm) in diameter 

in the greatest dimension of the onion at right angles to a line 

running from the stem to the root. 

(2) Type II- 3/8 inches (10 mm) to 7/8 inches (20mm) in diameter 

in the greatest dimension of the onion at right angles to a line 

running from the stem to the root.

(b) Strips means stemmed, peeled bulbs which have been randomly 

cut lengthwise into narrow pieces ranging from 3/4 inches (19 mm) 

to 2.0 inches (51 mm) in length. The width may vary between 1/4

inches (6 mm) to 3/4 inch (19 mm). 

(c) Diced means cut, or chopped stemmed, peeled bulbs which have

been cut randomly into approximate square pieces with a

designated width ranging from 1/4 inch (6 mm) to one inch (25 mm)

in width determined by the width or cross-section of the unit in the

greatest cut dimension. 

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

the size, shape, or other characteristic which differentiates it from 

other styles.

§52.4074 Requirements for style.

(a) Whole. 

(1) Type I. The units are well shaped and that approximately 10 

percent by count of the units (lot average) may be less than, 

7/8 inches (20 mm) or 5 percent greater than 1-7/8 inches (48 

mm) at the widest portion of the unit.
2

(2) Type II. The units are well shaped and that approximately 10 

percent by count of the units (lot average) may be less than

3/8 inch (10 mm)or 5 percent greater than 7/8 (20 mm) in the 

greatest portion of the unit. 

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

than the minimum style requirement of 3/4 inches in length.

(c) Diced style. The units are practically uniform in size and the 

aggregate weight of all the units which are noticeably smaller than

one-half the area of an average sized unit (or the designated size) 

does not exceed 30 percent, by weight, of all units, and of all the 

large and irregular-shaped units greater than 1-1/2 times the area of 

an average sized unit (or the designated size) do not exceed the 

weight by 30 percent of all units.

(d) Other. Units shall be reasonably uniform in size and shape 

provided that the overall appearance is not materially affected.

§52.4075 Definitions of terms.

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

defective units or the 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 free flowing, 

bright with practically uniform units. Markedly variable units, 

small specks or other factors, do not significantly affect the 

overall appearance or edibility of the frozen onions. 

(2) Reasonably good appearance means that the product is 

fairly free flowing, reasonably bright with reasonably uniform 

units. The overall appearance or edibility of the onion is 

slightly but not seriously affected by markedly variable units, 

small specks or other factors
3

(3) Poor appearance means that the product does not meet the 

requirements of reasonably good appearance.

(c) Blemished means the unit is affected or damaged by pathological 

injury, insect injury, or any other injury, which, affects overall

appearance or eating quality of the unit. 

(1) Minor blemish means a unit with tan to brown blemish(s), 

which in the aggregate, exceeds the area of a circle 1/8 

inches (2 mm) in diameter but not more than 1/4 inches (6 

mm) in diameter.

 

(2) Major blemish means a unit with a tan to dark blemish(s), 

which in the aggregate, exceeds the area of a circle 1/4 

inches (6 mm) in diameter.

(d) Character. Reference the firmness and texture of the individual 

onion unit and the degree of freedom from tough, soft, or mushy 

units.

(1) Good character means that the onions are reasonably firm,

reasonable tender, and are not soft and spongy.

(2) Reasonable good character means that the onion are 

fairly firm, fairly tender, and are not soft and spongy.

(3) Poor character means that the product fails to meets the 

requirements of paragraph 1 and 2.

(e) Color refers to the predominating and characteristic color of 

the exterior surface of the units of frozen onions.

(1) Good color means that the frozen onions have a good 

characteristic bright color typical of the variety.

(2) Reasonably good color means that the frozen onions have 

a reasonably good color typical of the variety and the units 

individually or collectively may vary slightly from bright to 

slightly dull. 

(3) Poor color means the units do not meet the requirement of 

reasonably good color.
4

(4) Core material means the fibrous portions of the onion bulb. 

This portion is part of the internal onion flesh and should not 

be discolored, excessively tough, fibrous, or soft and mushy. 

Core material may include sprouts, seed stems, root crown,

and root material and shall not exceed 3/8 inches (10 mm) in 

diameter or length, whichever is applicable. One unit is 

equivalent to one defect. 

(f) Dark Green units - units with dark green stripes across 50 percent 

or more of the onion unit is considered a defect.

 

(h) Defect means any nonconformance of a unit(s) of product from a 

specified requirement of a single quality characteristic.

(i) Extraneous vegetable material (EVM) means any plant material of 

onions or other plants including but not limited to the leaves or roots 

(aggregate of one inch in length or more).

(j) 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.

(k) 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.

(l) Peel means the thin outer skin of the bulb. Peel is usually creamy, 

white to brown in color, tough, and tissue-like. One defect is 

equivalent to 1/2 square inch (3.2 cm2

).

(m) Root crown means the tough fibrous material found on the bottom 

portion of the onion where the roots attach to the onion bulb. Portion

of the root crown exceeding 3/8 inches (10 mm) in diameter are 

scored as defect. Roots greater than 3/8 inches (10 mm) in length 

attached to the root crown are scored as one defect. 
5

(n) Sprouts mean the internal material that protrudes from the top or 

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

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

should not extend more than 1/4 inch (6 mm) from the neck of the 

onion. One unit is equivalent to one defect under “Core Material”. 

(o) Sample size means the amount of product specified to use for 

grading. For varietal characteristics, color, flavor and odor, and 

appearance, a sample size is the entire container. For blemishes, 

character, specified defects, mechanical damage, and loose scales, 

a sample size is 50 units by count for Whole style, or 450 grams by

weight for strips, diced, cut and other styles. It 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) Tolerance (TOL) means the percentage of defective units allowed 

for each quality factor for a specific sample size. 

(q) Unit means a whole peeled bulb, immature bulb, individual piece, or 

portion of such, in frozen onions.

(r) Grit or dirt means any particle of earthy material

§52.4076 Grades.

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

prerequisites in which the onions:

(1) Have similar varietal characteristics,

(2) Have a normal flavor and odor,

(3) Have a good color; 

(4) Have good appearance;
6

(5) Practically free from grit or dirt

(6) Are within the limits for defects as specified in Tables I and II 

of this subpart, as applicable for the style in Section 52.4073.

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

prerequisites in which the onions:

(1) Have similar varietal characteristics;

(2) Have a normal flavor and odor;

(3) Have a reasonably good color;

(4) Have reasonably good appearance; 

(5) Practically free from grit or dirt; 

(6) Are within the limits for defects as specified in Tables I and II 

of this subpart as applicable for the style in Section 52.4073.

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

requirements of U.S. Grade B.

§52.4077 Factors of quality.

 The grade of frozen onions is based on meeting the requirements 

for the following factors:

(a) Prerequisites;

(1) Varietal characteristics;

(2) Color;

(3) Flavor and odor;

(4) Appearance;

(5) Absence of grit or dirt
7

(b) Classified Quality Factors and Defects; 

(1) Poor colored units;

(2) Dark Green Units;

(3) Major blemishes;

(4) Minor blemishes;

(5) Total blemishes (Major, and Minor);

(6) Character;

(7) Mechanical Damage (In Whole style);

(8) Core Material;

(i) Seed stem, 

(ii) Sprouts exceeding 1/4 inch (6 mm) in length from the

neck of the onion,

(iii) Root Crown material exceeding 3/8 inch (10 mm) in 

diameter,

(iv) Root material exceeding 3/8 inches in length.

(9) EVM;

(i) Leaves,

(ii) Loose roots aggregate of 1 inch in length or greater.

(10) Peel.

§52.4078 Requirements for classified quality factors and defects.

(a) Sample size can be found in Section 52.4075 (q), Definition of Terms.

(b) Acceptance criteria for specified defects can be found in Tables I and

 II, that follow.
 

8

TABLE I

FROZEN ONION, DEFECTS WHOLE STYLE BASE ON 50 UNITS

GRADE A

1/ AQL calculated from tolerance (TOL) at 650 units

2/ Unofficial Samples

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 2/ 300 650 1050 1450

DEFECTS TOL AQL 1/ ACCEPTANCE NUMBERS

Dark Green Units 1 0.612 1 4 7 10 14

Poor Colored Units 5 3.8 4 17 33 50 67

Major blemished 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

Core Material 2 1.3 2 7 13 20 26

Peel (sq. in) 2 1.3 2 7 13 20 26

Character 3 2.9 3 13 26 39 53

Character “B” Grade 2 1.5 2 8 15 22 29

Character “SSTD” 1 .75 1 5 8 12 16

EVM (count) 1 0.612 1 4 7 10 14
 

9

TABLE I (Continued)

FROZEN ONION, DEFECTS WHOLE STYLE BASE ON 50 UNITS

GRADE B

 

1/ AQL calculated from tolerance (TOL) at 650 unit

2/ Unofficial Samples

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 2/ 300 650 1050 1450

DEFECTS TOL AQL 1/ ACCEPTANCE NUMBERS

Dark Green Units 2 1.3 2 7 13 20 26

Poorly Colored Units 8 6.4 6 26 52 80 108

Major blemished 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

Core Material 3 2.9 3 13 26 39 53

Peel (sq. in) 1⁄2 sq. inch = one defect 3 2.9 3 13 26 39 53

Character 4 3.8 4 17 33 50 67

Character “SSTD” 2 1.9 2 9 18 27 36

EVM (count) 2 1.3 2 7 13 20 26
 

10

TABLE II 

FROZEN ONION, DEFECTS IN STRIPS, DICED OR OTHER STYLES BASE ON 50 UNITS

GRADE A

 

1/ AQL calculated from tolerance (TOL) at 5850 unit

2/ Unofficial Sample

Sample Units X Sample Unit Size 1 x 450 6 x 450 13 x 450 21 x 450 29 x4 50

Units of Product ( by count) 450 2/ 2700 5850 9450 13050

DEFECTS TOL AQL 1/ ACCEPTANCE NUMBERS

Dark Green Units 0.11 0.056 1 3 6 9 12

Poorly Colored Units 0.88 0.696 6 26 51 79 106

Major blemished 0.22 0.144 2 7 13 19 26

Total Blemish (Major, Minor) 0.88 0.696 6 26 51 79 106

Core Material 0.44 0.325 3 13 26 40 53

Peel (sq. in) 1⁄2 sq. inch = one defect 0.22 0.144 2 7 13 19 26

Character Soft or Mushy 2.0 1.72 12 83 117 183 249

Character Soft or Mushy “B” Grade 1.0 .9 7 32 64 100 135

Character Soft or Mushy “SSTD” .5 .4 4 16 31 48 64

EVM (count) 0.11 0.056 1 3 6 9 12
 

11

TABLE II (Continued)

FROZEN ONION, DEFECTS IN STRIPS, DICED OR OTHER STYLES BASE ON 50 UNITS

GRADE B

 

1/ AQL calculated from tolerance (TOL) at 5850 unit

2/ Unofficial Samples

Sample Units X Sample Unit Size 1 x 450 6 x 450 13 x 450 21 x 450 29 x4 50

Units of Product ( by count) 450 2/ 2700 5850 9450 13050

DEFECTS TOL AQL 1/ ACCEPTANCE NUMBERS

Dark Green Units 0.22 0.144 2 7 13 19 26

Poorly Colored Units 2.0 1.72 12 57 117 183 249

Major blemished 0.67 1.72 5 20 39 60 81

Total Blemish (Major, Minor) 2.0 1.72 12 57 117 183 249

Core Material 0.88 0.696 6 26 51 79 106

Peel (sq. in) 1⁄2 sq. inch = one defect 0.22 0.144 2 7 13 19 26

Character Soft or Mushy 4.0 3.6 23 113 234 370 506

Character Soft or Mushy “SSTD” 2.0 1.8 13 60 122 191 260

EVM (count or weight) 0.22 0.144 2 7 13 19 26
 

12

§52.4079 Sample size

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

shall be as 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 onion is considered as meeting the requirements 

for style if the requirements in Section 52.4074 as applicable are not 

exceeded.

(b) Quality Factors. A lot of frozen onions is considered as meeting the 

requirements for quality if:

(1) The prerequisites specified in Section 52.4077 are met; and

(2) The Acceptance Numbers in Table I or II, 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 

requirements for quality and style if:

(1) The prerequisites specified in Section 52.4077 are met; and

(2) The requirements for style in Section 52.4074 and the 

Acceptable Quality Levels (AQL's) in Tables I and II, in Section 

52.4078, as applicable, are not exceeded.

Dated: 

 ________________________

Rayne Pegg

Administrator

Agriculture Marketing Service