United States

Department of

Agriculture

Agricultural

Marketing Service

Fruit and

Vegetable Division

Processed

Products 

Branch

Grading Manual

for 

Frozen 

Leafy Greens

February 1987
Frozen Leafy Greens

February 1987

2

This manual is designed for Processed Products Branch personnel of the U.S. Department of

Agriculture. Its purpose is to give background information and guidelines to assist in the

uniform application and interpretation of U.S. grade standards, other similar specifications and

special procedures.

The citation of any data, techniques, illustrations, copyrighted material, or pictorial

representation accredited to private authorship is used with the permission of the individuals or

sources cited. Unless a specific reference is cited, the information in this manual has compiled

or developed from sources available to the public as well as from technical knowledge of

personnel in the Department.

Compliance with the suggested guidelines in this manual does not excuse failure to comply with

the Federal Food, Drug, and Cosmetic Act or any other applicable Federal or State laws or

regulations.

Except for official USDA inspection aids or devices and color guides (or standards) produced

under license of the Department, the mention of any supplier, patented device, product, brand

name or equipment does not imply endorsement by the Department over any other similar, or

equally effective material.

Address inquires to:

Chief, Processed Products Branch

Fruit and Vegetable Programs, AMS

U.S. Department of Agriculture

STOP 0247

1400 Independence Ave., SW

Washington, DC 20250-0247
Frozen Leafy Greens

February 1987

3

CONTENTS

Page

Sampling Procedures ........................................................................................................................ 4

Non-quality Procedures ................................................................................................................... 4

Classification of Defects ................................................................................................................... 5

SUGGESTED ORDER FOR ON-LINE GRADING OF A SAMPLE UNIT

Leaf.......................................................................................................5

Chopped..................................................................................................13

Pureed...................................................................................................19

SPECIAL ON-LINE ORDER FOR ON-LINE GRADING OF A SAMPLE UNIT

Checking “Frozen Prerequisites”....................................................................21

Use of CuSum Plans for Prerequisite Quality Factors............................................21

SUGGESTED ORDER FOR LOT GRADING OF A SAMPLE

Leaf.....................................................................................................22

Chopped................................................................................................30

Pureed..................................................................................................36
Frozen Leafy Greens

February 1987

4

SAMPLING PROCEDURES

1. LOT (Stationary or moving lot).

USE THE FOLLOWING FILE CODES:

Regulations (109-A-1)

Sampling Procedures (120-A-1)

Lot Sampling Plan (125-A-1)

2. ON –LINE 

USE THE FOLLOWING FILE CODES:

Follow Regulations (109-A-1)

CuSum Sampling Plan (120-A-6)

Time Sampling (120-A-4)

In-Plant Inspection (160-A-1; 162-A-1)

Condition of Container (125-A-1)

NON-QUALITY PROCEDURES

FOLLOW 130-A-1 AND THESE FILE CODES:

1. Time Sampling (120-A-5)

2. Net Weight (128-A-10)

3. Fill of Container (128-A-40)

4. Thawing Procedures (130-A-34)

5. Cooking Procedures (130-A-38)

6. Enzyme Inactivation (135-A-12)
Frozen Leafy Greens

February 1987

5

CLASSIFICATION OF DEFECTS

Other than the prerequisite quality factors (such as “brightness,” “varietal characteristics,”

“character,” “blemished,” and “flavor and odor”), any unit of leafy greens which fails to meet a

requirement of the standards is classified as a defect. The defects are classified as “minor,”

“major,” “severe,” or “critical”. “Total all classes” of defects means “critical,” plus “severe,”

plus “major,” plus “minor”.

The tolerance for each class of defects is set to AQL’s (Acceptable Quality Levels). Usually, the

tolerance is the same as the number of defects that would have been allowed in the old U.S.

standards, a purchase specification, or other similar buying guide. But, the old tolerance might

have been adjusted slightly to consider newer methods of harvesting and processing product.

SUGGESTED ORDER FOR ON-LINE GRADING OF A SAMPLE UNIT 

LEAF STYLE

1. Select at random 3 00 g (10.6 oz) of leafy greens from the processing line.

2. Evaluate the sample unit for varietal characteristics and assign the letter grade (A or SSTD)

in the prerequisites section of the tally sheet.

3. Place the sample unit of leafy greens in water in a deep grading tray. Separate the leaves

using gentle agitation.

DO NOT DISCARD THE TRAY OF WATER AS IT WILL BE USED FOR GRIT AND

SILT CHECK LATER. (See step 8 of this procedure).

4. For spinach only, determine the weight of stem material in the sample unit.

NOTE: If it is obvious that the sample unit contains no more than 72 grams of stem material

and the preceding CuSum value is zero (0), it is unnecessary to determine the number of 12

gram increments. Assign a CuSum value of zero (0) and the letter grade “A” for stem

material.

Otherwise, use the following procedure. Separate the leaves with gentle agitation. Remove

the individual leaves from the water and cut off the attached stem just below the last point of

attachment of leaf material. Place the stem material on a dry, previously tared 8 mesh sieve. 

Allow the stem material to drain for two (2) minutes, and weigh. Record the number of 12g

increments of stem material (to the nearest 12 g) in the prerequisites section of the tally

sheet.
Frozen Leafy Greens

February 1987

6

SUGGESTED ORDER FOR ON-LINE GRADING OF A SAMPLE UNIT

LEAF STYLE (continuation)

For example:

52 grams of stem material = 4.33

12 grams

Record on the tally as 4 increments;

or

56 grams of stem material = 4.67

12 grams

Record on the tally as 5 increments

Compute the CuSum and assign the letter grade (A, B, or SSTD) for stem

material.

CAUTION: SEE “SPECIAL ON-LINE SAMPLING SITUATIONS; USE OF

CUSUM PLANS FOR PREREQUISITE QUALITY FACTORS.”

STEM MATERIAL

TOLERANCE

GRADE A GRADE B

AQL 1/ 20.0 25.0

1/ AQL expressed as defects per hundred units. (See Table 7 in File Code 109-A-1, 25

plan)
Frozen Leafy Greens

February 1987

7

5. Evaluate the sample unit for blemished areas. Any degree of blemish that adversely

affects the appearance or eating quality is counted. In other words, for leafy greens other

than leaf style spinach, 4 square centimeters (cm2) of dark brown discoloration (serious)

would be recorded as one blemished just as 4 cm2 of yellow discoloration (slight) would

be recorded as one blemished. Determine the aggregate area of the blemished portions. 

Record in the prerequisites section of the tally sheet the number of 4 cm2 increments (to

the nearest 4 cm2). For leaf style spinach, each 6 cm2 is counted as one defect (instead of

each 4 cm2) 
Frozen Leafy Greens

February 1987

8

SUGGESTED ORDER FOR ON-LINE GRADING OF A SAMPLE UNIT

LEAF STYLE (continuation)

For example, if you found the following blemished areas:

Aggregate area = 3.14 cm2 + 3.80 cm2 + 4 cm2 = 10.94 cm2

The number of 4 cm2 increments (to the nearest 4 cm2) equals 10.94 cm2 ÷ 4 cm2 = 2.74 = 3

increments. You would record this as 3 blemished in the prerequisites section of the tally sheet.

Compute the CuSum and assign the letter grade for blemished.

 5b. If you are grading spinach, 6 square centimeters would be recorded a one blemished. 

Follow the procedure as described in 5a but record the number of 6 cm2 increments (to

the nearest 6 cm2) in the prerequisite section of the tally sheet. For example, the

aggregate area determined in step 5a of 10.94 cm2 would be recorded as 10.94 cm2 ÷ 6

cm2 = 1.82 = 2 increments. Compute the CuSum and assign the letter grade for

blemished.

CAUTION: SEE “SPECIAL ON-LINE SAMPLING SITUATIONS; USE OF

CUSUM PLANS FOR PREREQUISITE QUALITY FACTORS.”
Frozen Leafy Greens

February 1987

9

TIMESAVER: To save time in computing area measurements of circular blemishes, you

could use the following adaptation of Inspection Aid No. 101 as a guide.

MILLIMETER DIAMETER

(square centimeters)
Frozen Leafy Greens

February 1987

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SUGGESTED ORDER FOR ON-LINE GRADING OF A SAMPLE UNIT

LEAF STYLE (continuation).

6. Evaluate the sample unit for root crowns, root stubs, and seed heads. Count and record on

the tally sheet under classified defects each piece of root crown and root stub; and seed

heads that are longer than 2.5 cm (1 in) or objectionable in appearance.

7. Remove all extraneous vegetable material (EVM) from the sample unit. Use the

definitions in the standards to group the EVM into “I,” “II,” and “ III”. Determine the

aggregate length of the EVM in each group. Record the Number of 2.5 increments of

EVM (to the nearest 2.5 cm) for each group in the classified defects section of the tally

sheet.

For example:

These defects should be classified and recorded as follows: 
Frozen Leafy Greens

February 1987

11

SUGGESTED ORDER FOR ON-LINE GRADING OF A SAMPLE UNIT

LEAF STYLE (continuation).

8. Remove any remaining leaf and stem material from the tray of water saved in step 3 of

this procedure, carefully pour off the water and recover the sediment in a 250 ml beaker. 

Add water and bring the beaker about 1⁄2 of its volume. If grit is detected in the sediment,

cook a separate sample unit according to USDA cooking instructions (130-A-38). If grit

is only slightly noticeable, classify as Grade A. If grit is more than slightly noticeable,

but not objectionable, classify as Grade B. If objectionable, classify as SStd. For

product containing soil or silt that is not gritty, and the appearance or eating quality is not

more that slightly, affected, classify the product as Grade A. If the appearance or eating

quality is more than slightly, but not seriously affected, classify the product as Grade B. 

If seriously affected, classify the product SStd.

9. Total the classes of defects on the tally sheet and compute the CuSum values as outlined

in File Code 120-A-6.

 10. Select at least one Standard sample unit size (300 g ) for each production period code. 

This sample unit is to be selected after the greens have been frozen. It may comprise one

container or multiple containers. (See Special On-Line Sampling Situations – Checking

“Frozen Prerequisites”).

 11. Open the container(s) and allow the product to thaw slightly. This will reduce

unnecessary breakage of the greens when they are removed from the container(s).

 12. Place the greens in warm water in a deep grading tray. With gentle agitation separate the

leaves.

 13. Evaluate the sample unit for brightness. Record the letter grade for brightness as “A” 

“B,” or “SSTD “ in the prerequisites section of the tally sheet.

 14. Cook a portion of the sample unit, according to Brach instructions for cooking frozen

vegetables, to evaluate flavor and odor. Include, in the portion to be cooked, any

“suspect” unit that could impart an off-flavor or odor. Assign the letter grade (A or

SSTD) for flavor and odor in the prerequisites section of the tally sheet.
Frozen Leafy Greens

February 1987

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SUGGESTED ORDER FOR ON-LINE GRADING OF A SAMPLE UNIT

LEAF STYLE (continuation)

 15. Also, evaluate the character of the cooked sample unit. Please be careful to evaluate

character based on the “type”of leafy greens. For example, mustard greens are expected

to be more difficult to chew than spinach. They should not be downgraded if the

character is typical of grade A mustard greens. Assign the letter grade (A, B, or SSTD)

for character is the prerequisites section of the tally sheet. 

CAUTION: DO NOT TO THE DEFECT TALLY ANY CLASSIFIED

DEFECTS FOUND DURING EXAMINATION OF THE LEAFY

GREENS FOR “FROZEN PREREQUISITES” FACTORS.

 16. Occasionally, equipment breakdown (flo-freeze unit, etc.) causes product deterioration. 

If the defective product is isolated, separately identified and set aside, don’t count it as a

portion of the production that is being run.

 17. Optionally, the entire evaluation of the sample unit and the classification of defects may

be made on the product directly out of the freezer. Use CuSum, but bypass the selection

of the sample unit from the production line prior to freezing.
Frozen Leafy Greens

February 1987

13

SUGGESTED ORDER FOR ON-LINE GRADING OF A SAMPLE UNIT

CHOPPED STYLE

1. Select at random 300 g (10.6 oz) of leafy greens from the processing line. Use a sample

unit size of 75g (2.65 oz) to evaluate all quality factors except grit or silt. Save the 225 g

balance for step 7 of this procedure.

2. Evaluate the sample unit for varietal characteristics and assign the letter grade (A or

SSTD) in the prerequisites section of the tally sheet.

3. Place the sample unit of leafy greens (75 g) in water in a deep grading tray. Separate the

greens using gentle agitation.

DO NOT DISCARD THE TRAY OF WATER. IT AND THE 225 G OF

GREENS NOT USED IN STEPS 4, 5, AND 6 WILL BE USED FOR GRIT AND

SILT CHECK LATER. (SEE STEP 7 OF THIS PROCEDURE.)

4. For chopped spinach only, evaluate the sample unit for stem material. Assign the letter

grade (A, B or SSTD) for stem material in the prerequisites section of the tally sheet. 
Frozen Leafy Greens

February 1987

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SUGGESTED ORDER FOR ON-LINE GRADING OF A SAMPLE UNIT

CHOPPED STYLE (continuation).

5. Evaluate the sample unit for blemished areas. Any degree of blemish that adversely

affects the appearance or eating quality is counted. In other words, 2 square centimeters

(cm2 ) of dark brown discoloration (serious) would be recorded as one blemished just as 

2 cm2 of yellow discoloration (slight) would be recorded as one blemished. Determine

the aggregate area of the blemished portions. Record in the prerequisites section of the

tally sheet the number of 2 cm2 increments (to the nearest 2 cm2) 

For example, if you found the following blemished areas:
Frozen Leafy Greens

February 1987

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SUGGESTED ORDER FOR ON-LINE GRADING OF A SAMPLE UNIT

CHOPPED STYLE (continuation)

5. Blemished (continuation)

Aggregate area = 0.5 + 0.75 + 1.0 + 0.5 + 0.5 + 0.25 = 3.5 cm2.

The number of 2 cm2 increments (to the nearest 2 cm2) = 3.5 cm2 ÷ 2 cm2 = 1.75 = 2

increments. You would record this as 2 blemished in the prerequisites sections of the tally

sheet.

Compute the CuSum and assign the letter grade for blemished.

CAUTION: SEE “SPECIAL ON-LINE SAMPLING SITUATIONS USE OF CUSUM

PLANS FOR PREREQUISITE QUALITY FACTORS.”

6. Remove all extraneous vegetable material (EVM) from the sample unit. Use the 

Definitions in the standards to group the EVM into “I,” “II,” and “III”. Determine the

aggregate length of the EVM in each group. Record the number of 1.3 cm increments of

EVM (to the nearest 1.3 cm) for each group in the classified defects section of the tally

sheet.
Frozen Leafy Greens

February 1987

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SUGGESTED ORDER FOR ON-LINE GRADING OF A SAMPLE UNIT

CHOPPED STYLE (continuation)

5. Blemished (continuation)

For example: The defects should be classified and recorded as follows:
Frozen Leafy Greens

February 1987

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SUGGESTED ORDER FOR ON-LINE GRADING OF A SAMPLE UNIT

CHOPPED STYLE (continuation).

7. Add the 225 g of greens saved in Step 1 of this procedure to the tray of water. Set aside in Step 3

and agitate gently. Then, remove all remaining leaf and stem material from the tray, carefully

pour off the water and recover the sediment in a 250 ml beaker. Add water and bring the beaker

to about 1⁄2 of its volume.

If grit is detected in the sediment, cook a separate sample unit according to Branch cooking

instructions. If grit is only slightly noticeable, classify as Grade A. If grit is more than slightly

noticeable, but not objectionable, classify as Grade B. If objectionable, classify as SSTD. For

product containing soil or silt that is not gritty and the appearance or eating quality is not more

than slightly affected, classify as Grade A. If the appearance or eating quality is more than

slightly, but not seriously affected, classify as Grade B. If seriously affected, classify as SSTD.

8. Total the classes of defects on the tally sheet and compute the CuSum values as outlined in File

Code 120-A-6.

9. Select at least one standard sample unit size (75 g) for each production period code. This sample

unit is to be selected after the greens have frozen. It may comprise one container or multiple

containers. (See Special On-Line Sampling Situations – Checking “Frozen Prerequisites”).

 10. Open the container (s) and allow the product to thaw slightly. This will reduce unnecessary

breakage of the breakage of the greens when they are removed from the container(s).

 11. Place the greens in warm water in a deep grading tray. With gentle agitation 

separate the greens.

 12. Evaluate the sample unit for brightness. Record the letter grade for brightness (A, B, or SSTD in

the prerequisites section of the tally sheet.

 

 13. Cook a portion of the sample unit according to Branch instructions for cooking frozen vegetables,

to evaluate flavor and odor. Include, in the portion to be cooked, any “suspect” units that could

impart an off flavor or odor. Assign the letter grade (A or SStd) for flavor and odor in the

prerequisites section of the tally sheet.
Frozen Leafy Greens

February 1987

18

SUGGESTED ORDER FOR ON-LINE GRADING OF A SAMPLE UNIT

CHOPPED STYLE (continuation)

 14. Also, evaluate the character of the cooked sample unit. Please be careful to evaluate

character based on the “type” of leafy greens. For example, mustard greens are expected

to be more difficult to chew than spinach. They should not be downgraded if the

character is typical of A grade mustard greens. Assign the letter grade (A, B, or SSTD)

for character in the prerequisites section of the tally sheet.

CAUTION: DO NOT ADD TO THE TALLY ANY CLASSIFIED DEFECTS

FOUND DURING EXAMINATION OF THE LEAFY GREENS FOR

“FROZEN PREREQUISITES” FACTORS.

 15. Occasionally, equipment breakdown (flo-freeze unit, etc.) causes product deterioration. 

If the defective product is isolated, separately identified and set aside, don’t count it as a

portion of the production that is being run.

 16. Optionally, the entire evaluation of the sample unit and the classification of defects may

be made on the product directly out of the freezer. Use CuSum, but bypass the selection

of the sample unit from the production line prior to freezing.
Frozen Leafy Greens

February 1987

19

SUGGESTED ORDER FOR ON-LINE GRADING OF A SAMPLE UNIT

PUREED STYLE

1. Select at random 75 g (2.65 oz) of leafy greens from the processing line.

2. Evaluate the sample unit for varietal characteristics and assign the letter grade (A or

SSTD) in the prerequisites section of the tally sheet.

3. Pour and spread the product evenly over the bottom of a shallow white tray. Count the

number of dark specks. Each two (2) specks is equal to one blemished. Record in the

prerequisites section of the tally sheet the number of blemished.

Compute the CuSum and assign the letter grade for blemished.

CAUTION: SEE “SPECIAL ON-LINE SAMPLING SITUATIONS; USE OF

CUSUM PLANS FOR PREREQUISITE QUALITY FACTORS.”

4. Remove all extraneous vegetable material (EVM) from the sample unit. Use the

definitions in the standards to group the EMV into “I,” “II,” and “III”. Determine the

aggregate length of the EVM in each group. Record the number of 1.3 cm increments of

EVM (to the nearest 1.3 cm) for each group in the classified defects section of the tally

sheet.

For example:

The number of defects should be determined as follows:

3 cm (aggregate length) ÷ 1.3 cm = 2.3 = 2 defects.

 1 cm (aggregate length) ÷ 1.3 cm = 0.77 = 1 defects.

5. Evaluate the sample unit for grit or silt by chewing. Assign the letter (A, B, or SSTD) for

grit or silt in the prerequisites section of the tally sheet.

6. Total the classes of defects on the tally sheet and compute the CuSum values as outlined

in File Code 120-A-6.
Frozen Leafy Greens

February 1987

20

SUGGESTED ORDER FOR ON-LINE GRADING OF A SAMPLE UNIT

PUREED STYLE (continuation)

7. Select at least one standard sample unit size (75g) for each production period code. This

sample unit is to be selected after the greens have been frozen. It may comprise one

container or multiple containers. (See Special On-Line Sampling Situations – checking

“Frozen Prerequisites”).

8. Thaw the product according to Branch instructions for thawing frozen vegetables in

sealed packages.

9. Evaluate the sample unit for brightness. Record the letter grade for brightness (A, B, or

SSTD) in the prerequisites section of the tally sheet.

 10. Cook a portion of the sample unit according to Branch instructions for cooking frozen

vegetables, to evaluate flavor and odor. Assign the letter grade (A or SSTD) for flavor

and odor in the prerequisites section of the tally sheet.

CAUTION: DO NOT ADD TO THE DEFECT TALLY ANY CLASSIFIED

DEFECTS FOUND DURING EXAMINATION OF THE LEAFY

GREENS FOR “FROZEN PREREQUISITES” FACTORS.

 11. Occasionally, equipment breakdown (flo-freeze unit, etc.) causes product deterioration. 

If the defective product is isolated, separately identified and set aside, don’t count it as a

portion of the production that is being run.

 12. Optionally, the entire evaluation of the sample unit and the classification of defects may

be made on the product directly out of the freezer. Use CuSum,but bypass the selection

of the sample unit from the production line prior to freezing.
Frozen Leafy Greens

February 1987

21

SPECIAL ON-LINE SAMPLING SITUATIONS

1. CHECKING “FROZEN PREREQUISITES”

Several prerequisite quality factors (such as flavor and odor) should be checked after

freezing. If the other quality factors are evaluated from sample units drawn from the

processing line (prior to freezing) you should evaluate at least one standard sample unit

size (300 g or 75 g) for each production period code. Because the product may be

inaccessible once it is warehoused, draw enough containers from the production line

(frozen) to satisfy the requirements of increased sampling, should you need the additional

containers. Any unopened containers could be returned to the freezer storage. Your

check might be done as follows:

a. Draw at least one standard sample unit size for each 30 minutes of production. Mark

the time. Evaluate one sample unit size from the period code. Accept the period if

the sample unit meets the intended grade. Open and evaluate the additional sample

units from the period code in question if the first one fails. Allow a failure to occur at

the rate in File Code 120-A-4 for time sampling deviants. If a failure does occur, the

recorded time of the “frozen prerequisites: check could be used to pinpoint the

portion of the period code containing the problem; or

b. Draw at least one container for each 30 minutes of production. Make sure that you

have enough product for one standard sample unit size from each period code. 

Composite all of the product from the period code and select at random one standard

sample unit size for examination. The period code would pass or fail based on just

one check. If a failure does occur, the exact time, or portion of the period code

containing the problem could not be pinpointed.

2. USE OF CUSUM PLANS FOR PREREQUISITE QUALITY FACTORS.

Consider prerequisite quality factors independent of the classified quality factors. 

Although the prerequisite quality factors of stem-material and blemished are set to AQLs

and appropriate CuSum sampling plans, don’t use the CuSum rules in File code 120-A-6

for these prerequisites, except for assigning a grade to the period code. (Example: If 2

sample units in a row fail the designated grade, don’t apply step 3 of HOW TO INSPECT

PRODUCTION in File Code 120-A-6).
Frozen Leafy Greens

February 1987

22

SUGGESTED ORDER FOR LOT GRADING A SAMPLE

LEAF STYLE

1. Follow the procedure outlined in File Code 120-A-7, Lot Single Sampling Plan

(Attributes)

2. Use the same defect tally sheet for lot grading as you would use for on-line grading. 

Ignore the section of the tally devoted to CuScum values.

NOTE: THE FOLLOWING PREREQUISITES ARE TO BE EVALUATED ON A

CONTAINER-BY-CONTAINER BASIS: BRIGHTNESS; VARIETAL

CHARACTERISTICS; GRIT OR SILT; ODOR (Tentative).

3. Weigh and record the net weight of each container.

4. Open each container and allow the product to thaw slightly. This will reduce further

breakage of the greens when they are taken from the container.

5. Carefully remove the greens from each container. Place them container by into deep

grading trays to thaw according to Branch instructions for thawing frozen vegetables.

6. With gentle agitation separate the leaves. Remove the greens from the water. 

TEMPORARILY SET ASIDE EACH TRAY OF WATER FOR SUBSEQUENT GRIT

AND SILT CHECK. (See step 15 of this procedure).

7. Spread the greens on shallow grading trays and evaluate on a container by container basis

the following prerequisite s:

a. Evaluate “brightness” and record the letter grade (A, B or SSTD) in the prerequisites

section of the tally sheet;

b. Assign the letter grade (A or SSTD) for “varietal characteristics” in the section for

prerequisites;

c. Evaluate the greens for “odor”. Any container with product “suspect” of having an

off-odor should be retained for evaluation of flavor and odor at a later step in this

procedure. The “suspect” greens should be kept physically separate from the

containers, but must be evaluated for classified defects before cooking. If no off-odor

is detected, tentatively assign the letter grade “A” for flavor and odor in the

prerequisites section of the defect tally.
Frozen Leafy Greens

February 1987

23

SUGGESTED ORDER FOR LOT GRADING OF A SAMPLE

LEAF STYLE (continuation).

8. Assemble mentally or physically (except any “suspect” off-odor greens as mentioned in

step 7) all of the greens from all of the containers into one sample. Adjust the total weight

of the leafy greens to equal one of the following sample sizes:

See 120-A-7 Supplement 1, 300 grams/25 plan = 12 gram increments

936 g

(33.0 oz)

78x12

1512 g

(53.3 oz)

126x12

1800 g

(63.5 oz)

150x12

2028 g

(71.5 oz)

169x12

2088 g

(73.6 oz)

174x12

3276 g

(115.6 oz)

273x12

3600 g

(127.0 oz)

300x12

3900 g

(137.6 oz)

325x12

4524 g

(159.6 oz)

377x12

6300 g

(222.2 oz)

525x12

7200 g

(254.0 oz)

600x12

7800 g

(275.1 oz)

650x12

8700 g

(306.9 oz)

725x12

The acceptance number for 3276 grams of product are found in

Supplement 1 under column "273", for example.

9. Evaluate the sample for root crowns, root stubs, and seed heads. Count and record on the

tally sheet under classified defects each piece of root crown and root stub; and seed heads

that are longer than 2.5 cm (1 in) or objectionable in appearance.

 10. Remove all extraneous vegetable material (EVM) from the sample. Use the definitions

in the standards to group the EVM into “I,” “II,” and “III:. Determine the aggregate

length of the EVM in each group. Record the number of 2.5cm increments of EVM (to

the nearest 2.5cm) for each group in the classified defects section of the tally sheet. 

(Please see example on the next page).
Frozen Leafy Greens

February 1987

24

SUGGESTED ORDER FOR LOT GRADING OF A SAMPLE

LEAF STYLE (continuation).

10. EVM (continuation).

 

11a. Evaluate the sample for blemished areas. Any degree of blemish that adversely affects

the appearance or eating quality is counted. In other words for leafy greens other than

spinach, 4 square centimeters (cm2) of dark brown discoloration (serious) would be

recorded as one blemished just as 4 cm2 of yellow discoloration (slight) would be

recorded as one blemished. Determine the aggregate area of the blemished portions. 

Record in the prerequisites section of the tally sheet the number of 4 cm2 increments (to

the nearest 4 cm2). For leaf style spinach, each 6 cm2 is counted as one defect (instead of 

each 4 cm2).
Frozen Leafy Greens

February 1987

25

SUGGESTED ORDER FOR LOT GRADING OF A SAMPLE

LEAF STYLE (continuation).

For example, if you found the following blemished areas:

 

 

Aggregate area = 3.14 cm2 + 3.80 cm2 + 4 cm2 = 10.94 cm2

The number of 4 cm2 increments (to the nearest 4 cm2) = 10.94 cm2 ÷ 4 cm2 = 2.74 = 3

increments. You would record this as 3 blemished in the prerequisites section of the tally sheet. 

Assign the letter grade (A, B, or SSTD) for blemished based on the tolerances shown below in

the Prerequisites section of the tally sheet.

 11b. If you are grading spinach, 6 square centimeters would be recorded as one blemished. 

Follow the procedure as described in 11a but record the number of 6 cm2 increments (to

nearest 6 cm2) in the prerequisite section of the tally sheet.
Frozen Leafy Greens

February 1987

26

SUGGESTED ORDER FOR LOT GRADING A SAMPLE

LEAF STYLE (continuation)

For example, the aggregate area determined in step 11a of 10.94 cm2 would be

recorded as the 10.94 cm2 ÷ 6cm2 = 1.82 = 2 increments. Assign the letter grade (A,B,

or SSTD) for blemished based on the tolerances shown below.

Lot Tolerance for Blemished

(number of 4 cm2 or 6 cm2 increments)

Sample

size

(grams)

A B Sample

size

(grams)

A B

 936 22 40 3900 78 149

1512 33 62 4524 90 171

1800 39 73 6300 122 234

2028 43 81 7200 138 266

2088 44 83 7800 149 287

3297 67 126 8700 165 318

3600 73 138

For leaf style spinach, use the table above, however, each defect for blemishes will be

based on 6 cm2 increments.
Frozen Leafy Greens

February 1987

27

TIMESAVER: To save time in computing area measurements of circular blemishes,

you could use the following adaptation of Inspection Aid No. 101 as a

guide.

MILLIMETER DIAMETER

(square centimeters)
Frozen Leafy Greens

February 1987

28

SUGGESTED ORDER FOR LOT GRADING OF A SAMPLE

LEAF STYLE (continuation).

12. For spinach only, determine the weight of stem material in the sample. 

Time Saver: If you are using a larger sample for classified quality defects, you

may use a smaller sample for weighing stem material. This option would be equal

to drawing a subsample. For example, if you are using a 6300 g (222.2 oz) sample

for classified defects, you could choose a smaller sample size for stem material

such as 936 g (33.0 oz); 1512 g (53.3 oz); or 1800 g (63.5 oz) etc. If you use a

smaller sample size for weighing stem material, note on the tally sheet that you

used the smaller sample. Otherwise, it is difficult for someone else to re-evaluate

the defect tally.

Use the following procedure. Remove the individual leaves from the tray and cut

off the attached stem just below the last point of attachment of leaf material. Place

the stem material on a dry, previously tared # 8 mesh sieve. Allow the stem

material to drain for 2 minutes, and weigh. Record the number of 12 g increments

of stem material (to the nearest 12 g) in the prerequisite section of the tally sheet.

For example:

52 grams of stem material = 4.33

12 grams

Record on the tally sheet as 4 increments; or 

56 grams of stem material = 4.67

12 grams

Record on the tally as 5 increments.

Assign the letter grade (A, B, or SSTD) for stem material based on the tolerance shown on

the next page.
Frozen Leafy Greens

February 1987

29

SUGGESTED ORDER FOR LOT GRADING OF A SAMPLE

LEAF STYLE (continuation).

12. Spinach stem material (continuation).

Spinach Stem Material

Lot Tolerance

(number of 12 g increments)

Sample size

(grams)

A B Sample size

(grams)

A B

936 22 27 3900 78 96

1512 33 41 4524 90 110

1800 39 48 6300 122 150

2028 43 53 7200 138 170

2088 44 54 7800 149 183

3276 67 82 8700 165 203

3600 73 89

13. Cook a portion of the sample, according to Branch instructions for cooking frozen

vegetables, to evaluate flavor and odor. 

NOTE: Cook separately any "suspect" or off-odor greens retained in step 7c of

this procedure. If the "suspect " greens have a normal flavor and odor after

cooking, they should be assigned grade "A" for "flavor and odor". Assign the

letter grade (A or SSTD) for the sample (not each container) for "flavor and odor"

in the "prerequisites" section of the tally sheet.
Frozen Leafy Greens

February 1987

30

SUGGESTED ORDER FOR LOT GRADING OF A SAMPLE

LEAF STYLE (continuation).

14. Also, evaluate the character of the cooked sample. Please be careful to evaluate

character based on the "type" of leafy greens. For example, mustard greens are

expected to be more difficult to chew than spinach. They should not be

downgraded if the character is typical of “A” grade mustard greens. Assign the

letter grade (A, B, or SSTD) for character in the prerequisites section of the defect

tally.

15. Discard container by container most of the contents of each tray of water saved in

step 6 of this procedure. Recover the sediment from each tray in the 250 ml

beaker.

16. Add water and bring each beaker to about 1⁄2 of its volume. If grit is detected in

the sediment, cook a separate sample unit according to Branch cooking

instructions. If grit is only slightly noticeable, classify as grade A. If grit is more

than slightly noticeable, but not objectionable, classify as Grade A. If the

appearance or eating quality is more than slightly, but not seriously affected,

classify as SSTD.

17. Compare the total number of defects that you found in the sample (not each

container) with the acceptance number for the applicable AQL and sample size in

File Code 120-A-7, Supplement I.

18. Assign a grade to the sample based on the procedure outlined in 

File Code 120-A-7, Lot Single Sampling Plan.
Frozen Leafy Greens

February 1987

31

SUGGESTED ORDER FOR LOT GRADING OF A SAMPLE

CHOPPED STYLE

1. Follow the procedure outlined in File Code 120-A-7, Lot Single Sampling Plan

(Attributes).

2. Use the same defect tally sheet for lot grading as you would use for on-line

grading. Ignore the section of the tally devoted to CuSum values.

NOTE: THE FOLLOWING PREREQUISITES ARE TO BE EVALUATED

ON A CONTAINER BY CONTAINER BASIS: BRIGHTNESS;

VARIETAL CHARACTERISTICS; GRIT OR SILT; ODOR

(Tentative).

3. Weigh and record the net weight of each container.

4. Open each container and allow the product to thaw slightly.

5. Carefully remove the greens form each container. Place them container by

container into deep grading trays to thaw according to Branch instructions for

thawing frozen vegetables.

6. With gentle agitation, separate the leaves. Remove the greens from the water. 

TEMPORARILY SET ASIDE EACH TRAY OF WATER FOR SUBSEQUENT

GRIT AND SILT CHECK. (See step 14 of this procedure).

7. Spread the greens on shallow grading trays and evaluate on a container by

container basis the following prerequisites:

a. Evaluate "brightness" and record the letter grade (A, B, or SSTD) in the

prerequisites section of the tally sheet;

b. Assign the letter grade (A or SSTD) for "varietal characteristics" in the

section for prerequisites;
Frozen Leafy Greens

February 1987

32

SUGGESTED ORDER FOR LOT GRADING OF A SAMPLE

CHOPPED STYLE (continuation).

c. Evaluate the greens for "odor". Any container with product "suspect" of

having an off odor should be retained for evaluation of flavor and odor at a

later step in this procedure. The "suspect" greens should be kept physically

separate form the other containers, but must be evaluated for classified defects

before cooking. If no off-odor is detected, tentatively assign the letter grade

"A" for the flavor and odor in the prerequisites section of the tally sheet.

8. Assemble mentally or physically (except any "suspect" or off-odor greens as

mentioned in step 7c) all of the greens from all of the containers into one sample. 

Adjust the total weight of the leafy greens to equal one of the following sample

sizes:

See 120-A-7, Supplement 1, 75 grams/ 25plan = 3 gram increments.

108 g

(3.8 oz)

36x3

234 g

(8.3 oz)

78x3

378 g

(13.3 oz)

126x3

450 g

(15.9 oz)

150x3

507 g

(17.9 oz)

169x3

522 g

(18.4 oz)

174x3

819 g

 (28.9 oz)

273x3

900 g

(31.7 oz)

300x3

975 g

(34.4 oz)

325x3

1131 g

(39.9 oz)

377x3

1575 g

(55.6 oz)

525x3

1800 g

(63.5 oz)

600x3

1950 g

(68.8 oz)

650x3

2175 g

(76.7 oz)

725x3

The acceptance numbers for 819 grams of product are

found in Supplement I, under column “273", for

example.

9. Remove all extraneous vegetable material (EVM) from the sample. Use the

definitions in the standards to group the EVM into "I ", "II", and "III". Determine

the aggregate length of the EVM in each group. Record the number of 1.3 cm

increments of EVM (to the nearest 1.3 cm) for each group in the classified defects

section of the tally sheet.
Frozen Leafy Greens

February 1987

33

SUGGESTED ORDER FOR LOT GRADING OF A SAMPLE

CHOPPED STYLE (continuation).

For example:

These defects should be classified and recorded as follows:

Group I

Group III

10. Evaluate the sample for blemished areas. Any degree of blemish that adversely affects

the appearance or eating quality is counted. In other words, 2 square centimeters (cm2) of

dark brown discoloration (serious) would be recorded as one blemish just as 2 cm2

increments (to the nearest 2 cm2) of yellow discoloration (slight) would be recorded as

one blemished. Determine the aggregate area of the blemished portions. Record in the

prerequisites section of tally sheet under classified defects the number of 2 cm2

increments (to the nearest 2 cm2). 
Frozen Leafy Greens

February 1987

34

SUGGESTED ORDER FOR LOT GRADING OF A SAMPLE

CHOPPED STYLE (continuation).

For example, if you found the following blemished areas:

Aggregate area = 0.5 + 0.75 + 1.0 + 0.5 + 0.5 + 0.25 = 3.5 cm2.

The number of 2 cm2 increments ( to the nearest 2 cm2 ) = 3.5 cm2 ÷ 2 cm2 = 1.75 = 

2 increments. You would record this as 2 blemished in the prerequisites section of the

tally sheet.
Frozen Leafy Greens

February 1987

35

SUGGESTED ORDER FOR LOT GRADING OF A SAMPLE

CHOPPED STYLE (continuation).

10. Blemished (continuation).

Assign the letter grade (A, B, SSTD) for blemished based on the tolerance shown below.

Lot Tolerance for Blemished

(number of 2 cm2 increments)

Sample size

 (grams)

A B Sample size

 (grams)

A B

108 12 21 900 73 138

234 22 40 975 78 149

378 33 62 1131 90 171

450 39 73 1575 122 234

507 43 81 1800 138 266

522 44 83 1950 149 287

819 67 126 2175 165 318

11. For chopped Spinach only, evaluate the sample for stem material. Assign the

letter grade (A, B, or SSTD) for stem material in the prerequisites section of the

tally sheet.

12. Cook a portion of the sample, according to Branch instructions for cooking frozen

vegetables, to evaluate flavor and odor. 

NOTE: Cook separately any “suspect” off-odor greens retained in step 7c of this

procedure. If the “suspect” greens have a normal flavor and odor after cooking,

they should be assigned grade “A” for “flavor and odor”. Assign the letter grade

(A or SSTD) for the sample (not each container) for “flavor and odor” in the

“prerequisites” section of the defect tally.
Frozen Leafy Greens

February 1987

36

SUGGESTED ORDER FOR LOT GRADING OF A SAMPLE

CHOPPED STYLE (continuation).

13. Also, evaluate the character of the cooked sample. Please be careful to

evaluate character based on the “type” of leafy green. For example, mustard

greens are expected to be more difficult to chew than spinach. They should

not be downgraded if the character is typical of “A” grade mustard greens. 

Assign the letter grade (A, B, or SSTD) for character in the prerequisites

section of the defect tally.

14. Discard, container by container, most of the contents of each tray of water

saved in step 6 of this procedure. Recover the sediment tray by tray in 250 ml

beakers.

15. Add water and bring each beaker to about 1⁄2 of its volume. If grit is detected

in the sediment, cook a separate sample unit according to Branch cooking

instructions. If grit is only slightly noticeable, classify as Grade A. If grit

more than slightly noticeable, but not objectionable, classify as Grade B. If

objectionable, classify as SSTD. For product containing soil or silt that is not

gritty and the appearance or eating quality is not more than slightly affected,

classify as Grade A. If the appearance or eating quality is more than slightly,

but not seriously affected, classify as Grade B. If seriously affected, classify

as SSTD.

16. Compare the total number of defects that you found in the sample (not each

container) with the acceptance number for the applicable AQL and sample

size in File Code 120-A-7, Supplement I.

17. Assign a grade to the sample based on the procedure outlined in 

File Code 120-A-7, Lot Single Sampling Plan. 
Frozen Leafy Greens

February 1987

37

SUGGESTED ORDER FOR LOT GRADING OF A SAMPLE

PUREED STYLE 

1. Follow the procedure outlined in File Code 120-A-7, Lot single Sampling Plan

(Attributes).

2. Use the same tally sheet for lot grading as you would for on-line grading. Ignore

the section of the tally devoted to CuSum values.

NOTE: THE FOLLOWING PREREQUISITES ARE TO BE EVALUATED

ON A CONTAINER BY CONTAINER BASIS: BRIGHTNESS;

VARIETAL CHARACTERISTICS; GRIT OR SILT; AND ODOR

(Tentative).

3. Weigh and record the net weight of each container.

4. Thaw the product according to Branch instructions for thawing frozen vegetables

in sealed packages.

5. Pour the product, container by container, or a representative subsample for each

container, into shallow white bottom trays and spread the product evenly over the

bottoms of the trays.

6. On a container by container basis:

a. Evaluate “brightness” and record the letter grade (A, B, or SSTD) in the

prerequisites section of the tally sheet;

b. Assign the letter grade (A or SSTD) for varietal characteristics in the section

for prerequisites;

c. Evaluate the greens for “odor”. Any container with product “suspect” of

having an off-odor should be retained for evaluation of flavor and odor at a

later step in this procedure. The “suspect” greens should be kept physically

separate from the other containers, but must be evaluated for classified defects

before cooking. If no off-odor is detected, tentatively assign the letter grade

“A” for flavor and odor in the prerequisites section of the tally sheet.
Frozen Leafy Greens

February 1987

38

SUGGESTED ORDER FOR LOT GRADING OF A SAMPLE

PUREED STYLE 

d. Evaluate the greens for grit or silt by chewing. Assign the letter grade (A, B,

or SSTD) for grit or silt in the prerequisites section of the tally sheet.

7. Assemble mentally or physically (except any “suspect” off-odor greens as

mentioned in step 6c) all of the greens from all of the containers into one sample. 

Adjust the total weight of the leafy greens to equal one of the following sample

sizes:

See 120-A-7, Supplement 1, 75 grams/25 plan = 3 gram increments

108 g

(3.8 oz)

36x3

234 g

(8.3 oz)

78x3

378

(13.3 oz)

126x3

450 g

(15.9 oz)

150x3

507 g

(17.9 oz)

169x3

522 g

(18.4 oz)

174x3

819 g

(28.9 oz)

273x3

900 g

(31.7 oz)

300x3

975 g

(34.4 oz)

325x3

1131 g

(39.9 oz)

377x3

1575 g

(55.6 oz

525x3

1800 g

(63.5 oz)

600x3

1950 g

(68.8 oz)

650x3

2175 g

(76.7 oz)

725x3

The acceptance numbers for 819 grams of

product are found in 120-A-7 under column

“273" for example.

8. Remove all obvious pieces of extraneous vegetable material (EVM) from the

sample. Use the definitions in the standards to group the EVM into “I”, “II” and

“III”. Determine the aggregate length of EVM in each group. Record the number

of 1.3 cm increments of EVM (to the nearest 1.3 cm) for each group in the

classified defects section of the tally sheet.
Frozen Leafy Greens

February 1987

39

SUGGESTED ORDER FOR LOT GRADING OF A SAMPLE

PUREED STYLE Continued.

For example:

The number of defects should be determined as follows:

3 cm (aggregate length) ÷ 1.3 cm = 2.3 = 2 defects.

1 cm (aggregate length) ÷ 1.3 cm = 0.77 = 1 defect.

9. Evaluate the sample for blemished areas. With the product spread evenly

over the bottom of the trays, count the number of dark specks. Each two (2)

specks is equal one blemished. Divide the total number of specks by two (2)

to determine the number of blemished. Record the number of blemished in

the prerequisites section of the tally sheet.

Assign the letter grade (A, B, or SSTD) for blemished based on the tolerance

shown below.

Lot Tolerance for Blemished

(number of blemish)

Sample size

(grams)

A B Sample size

(grams)

A B

108 12 21 900 73 138

234 22 40 975 78 149

378 33 62 1131 90 171

450 39 73 1575 122 234

507 43 81 1800 138 266

522 44 83 1950 149 287

819 67 126 2175 165 318
Frozen Leafy Greens

February 1987

40

SUGGESTED ORDER FOR LOT GRADING OF A SAMPLE

PUREED STYLE 

10. Cook a portion of the sample, according to Branch instructions for cooking frozen

vegetables, to evaluate flavor and odor.

NOTE: Cook separately any “suspect” off-odor greens retained in step 6c of this

procedure. If the “suspect” greens have a normal flavor and odor after cooking,

they should be assigned grade “A” for “flavor and odor”. Assign the letter (A or

SSTD) for the sample (not each container) for “flavor and odor” in the

“prerequisites” section of the tally sheet.

11. Compare the total number of defects that you found in the sample (not each

container) with the acceptance number for the applicable number for the

applicable AQL and sample size in File Code 120-A-7, Supplement I.

12. Assign a grade to the sample based on the procedure outlined in File Code 120-

A7, Lot Single Sampling Plan.