United States

Department of

Agriculture

Agricultural 

Marketing

Service

Fruit and

Vegetable

Division

Fresh

Products

Branch

United States Standards

for Grades of

Lettuce

Effective December 1, 1975

(Reprinted - January 1997)
Packing of the product in conformity with the requirements of these standards shall not excuse failure to 1

comply with the provisions of the Federal Food, Drug and Cosmetic Act or with applicable State laws and regulations.

1

United States Standards for Grades of Lettuce1

Grades 

51.2510 U.S. Fancy.

51.2511 U.S. No. 1.

51.2512 U.S. No. 2.

Tolerances 

51.2513 Tolerances.

Application of Tolerances 

51.2514 Application of tolerances.

Precooling Requirements 

51.2515 Precooling requirements.

Standard Pack 

51.2516 Standard pack.

Standard Weight 

51.2517 Standard weight.

Solidity Classification 

51.2518 Solidity classification.

Definitions 

51.2519 Similar varietal characteristics.

51.2520 Fresh.

51.2521 Green.

51.2522 Burst.

51.2523 Doubles.

51.2524 Fairly well trimmed.

51.2525 Closely trimmed.

51.2526 Reasonably trimmed.

51.2527 Cap leaf.

51.2528 Crown.

51.2529 Injury.

51.2530 Damage.

51.2531 Serious damage.

51.2532 Permanent defects.

51.2533 Condition defects.

51.2534 Classification of defects.
2

Grades 

§51.2510 U.S. Fancy.

"U.S. Fancy'' consists of heads of lettuce which meet the following requirements:

(a) Basic requirements:

(1) Similar varietal characteristics;

(2) Fresh;

(3) Green;

(4) Not soft;

(5) Not burst;

(b) Free from:

(1) Decay;

(2) Russet spotting;

(3) Doubles;

(c) Free from injury by:

(1) Tipburn;

(2) Downy mildew;

(3) Field freezing;

(4) Discoloration;

(d) Not damaged by any other cause.

(e) Each head shall be fairly well trimmed unless specified as closely trimmed.

(f) For tolerances see §51.2513.

§51.2511 U.S. No. 1. 

"U.S. No. 1'' consists of heads of lettuce which meet the following requirements:

(a) Basic requirements:

(1) Similar varietal characteristics;

(2) Fresh;

(3) Green;

(4) Not soft;

(5) Not burst;

(b) Free from:

(1) Decay;

(2) Doubles.

(c) Not damaged by any other cause.

(d) Each head shall be fairly well trimmed unless specified as closely trimmed.

(e) For tolerances see §51.2513.

§51.2512 U.S. No. 2. 

"U.S. No. 2'' consists of heads of lettuce which meet the following requirements:

(a) Basic requirements:

(1) Similar varietal characteristics;

(2) Not burst;

(b) Free from decay;

(c) Not seriously damaged by any other cause;

(d) Unless otherwise specified each head shall be reasonably trimmed.
Shipping point, as used in these standards, means the point of origin of the shipment in producing area or at 2

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.

3

(e) For tolerances see §51.2513.

Tolerances 

§51.2513 Tolerances.

In order to allow for variations incident to proper grading and handling the following tolerances,

by count, shall be permitted in any lot:

(a) U.S. Fancy -- (1) For defects at shipping point. 8 percent for heads of lettuce which fail to 2 

meet the requirements of this grade: Provided, That included in this amount not more than 5

percent shall be allowed for soft heads: And provided further, That not more than 4 percent shall

be allowed for defects causing serious damage; included in this latter amount not more than 1

percent for heads which are affected by decay on any portion of the head exclusive of the wrapper

leaves.

(2) En route or at destination. 12 percent for heads of lettuce which fail to meet the

requirements of this grade: Provided, That included in this amount not more than the following

percentages shall be allowed for defects listed:

(i) 8 percent for heads having permanent defects including therein not more than 5 percent for soft

heads; or,

(ii) 6 percent for heads which are seriously damaged; including therein not more than 4 percent

for heads seriously damaged by permanent defects and not more than 3 percent for heads which

are affected by decay on any portion of the head exclusive of the wrapper leaves. (See §51.2514.) 

(b) U.S. No. 1 -- (1) For defects at shipping point. 8 percent for heads of lettuce which fail to 2

meet the requirements of this grade: Provided, That included in this amount not more than 5

percent shall be allowed for soft heads: And provided further, That not more than 4 percent shall

be allowed for defects causing serious damage, included in this latter amount not more than 1

percent for heads which are affected by decay on any portion of the head exclusive of the wrapper

leaves.

(2) En route or at destination. 12 percent for heads of lettuce which fail to meet the

requirements of this grade: Provided, That included in this amount not more than the following

percentages shall be allowed for defects listed:

(i) 8 percent for heads having permanent defects including therein not more than 5 percent for soft

heads; or,

(ii) 6 percent for heads which are seriously damaged; including therein not more than 4 percent

for heads seriously damaged by permanent defects and not more than 3 percent for heads which

are affected by decay on any portion of the head exclusive of the wrapper leaves. (see §51.2514.) 

(c) U.S. No. 2 -- (1) For defects at shipping point. 8 percent for heads of lettuce which fail to 2

meet the requirements of this grade: Provided, That included in this amount not more than 3

percent shall be allowed for heads which are affected by decay on any portion of the head

exclusive of the wrapper leaves.

(2) En route or at destination. 12 percent for heads of lettuce which fail to meet the

requirements of this grade: Provided, That included in this amount not more than the following
4

percentages shall be allowed for defects listed:

(i) 8 percent for heads having permanent defects; or,

(ii) 5 percent for heads which are affected by decay on any portion of the head exclusive of the

wrapper leaves. (See §51.2514.)

Application of Tolerances 

§51.2514 Application of tolerances.

(a) In order to meet the requirements of a specified grade the average percentage of defective

specimens in the lot, based on sample inspection shall be within the tolerances specified, and the

number of defective specimens in individual packages in the lot shall be within the limitations set

forth in the following table:

Table I -- Maximum Number of Defective Heads Permitted in Any Package

Lot tolerance, Total number of heads in package

 percent

24 18 or 20 30 Over 30

1 1 1 2 2

3 3 2 3 4

4 3 3 4 4

5 3 3 4 5

6 4 3 5 6

8 5 4 6 7

12 6 5 7 9

Precooling Requirements 

§51.2515 Precooling requirements.

The following precooling requirements may be used in certifying lettuce in the producing area:

(a) Lettuce certified as meeting "Precooling Requirements'' in the producing area shall have a core

temperature of not more than 36E F (2.2 E C) when placed in a refrigerated conveyance or

storage.

(1) The temperature shall be taken near the center of the head with a thermometer which has

previously been cooled to the approximately temperature of the lettuce. 

Standard Pack 

§51.2516 Standard pack.

(a) Heads of lettuce shall be fairly uniform in size, and fairly tightly to tightly packed but not

excessively tightly packed in uniform layers in the container according to the approved and

recognized methods; except that in standard fiberboard containers a "bridge'' of 6 heads may be

placed between the layers in a 2 1/2 dozen pack.

(1) Fairly uniform in size means that not more than 10 percent, by count, of heads in any container

may vary appreciably in size from the standard size head for the count pack.
The color referred to is illustrated by plate 5 GY 8/6 in the Munsell Book of Color. Individual plates of the 3

above color may be purchased from the Munsell Color Co., 2441 North Calvert, Baltimore, Md. 21218. 

5

(i) The standard size head for a 2 dozen pack is that size head, having 4 wrapper leaves, which

will pack tightly but not excessively tightly, 3 rows with 4 heads of uniform size in each row in a

layer in a standard fiberboard container. Heads having lesser or greater numbers of wrapper leaves

which can be packed as specified herein are considered equivalent in size to a standard size head

with 4 wrapper leaves.

(2) Excessively tightly packed means that heads are packed so tightly as to cause distortion, or

crushing of the heads or breaking of the midribs.

(b) When heads of lettuce are wrapped no head may have more than 1 wrapper leaf.

(c) In order to allow for variations incident to proper packing not more than a total of 10 percent

of the containers in any lot may fail to meet the requirements of standard pack.

Standard Weight 

§51.2517 Standard weight.

(a) The following weight requirements may be used in connection with grade.

(1) Lettuce packed in a standard lettuce containers shall have a net weight of not less than 42

pounds (19 kg) and not more than 50 pounds (23 kg).

(b) In order to allow for variations incident to proper packing, not more than a total of 5 percent

of the containers in any lot may fail to meet the requirements of standard weight.

Solidity Classification 

§51.2518 Solidity classification.

(a) Solidity of lettuce may be specified in connection with the grade in accordance with any of the

following classification:

(1) Hard. "Hard'' means that the head is compact and solid. This term represents the highest

degree of solidity.

(2) Firm. "Firm'' means that the head is compact, but may yield slightly to moderate pressure.

(3) Fairly firm. "Fairly firm'' means that although the head is not firm, it is not soft and spongy,

and has good head formation.

(4) Soft. "Soft'' means that the head is easily compressed or spongy.

Definitions 

§51.2519 Similar varietal characteristics.

"Similar varietal characteristics" means that the heads in any container have the same

characteristic leaf growth. For example, lettuce of the Iceberg and Big Boston types shall not be

mixed.

§51.2520 Fresh. 

"Fresh" means that the head as a whole has normal succulence and the wrapper leaves and the

outermost head leaves are not more than slightly wilted.

§51.2521 Green. 

"Green" means that one-half or more of the exterior surface of the head, exclusive of the wrapper

leaves, has at least a light green color.3

§51.2522 Burst. 

"Burst" means that the head is split or broken open.
6

§51.2523 Doubles. 

"Doubles" means two heads on the same stem.

§51.2524 Fairly well trimmed. 

"Fairly well trimmed" means that the butt is trimmed off closely below the point of attachment of

the outer leaves, and that on a head of Iceberg type lettuce, wrapper leaves do not exceed 7 in

number.

§51.2525 Closely trimmed. 

"Closely trimmed" means that the butt is trimmed off closely below the point of attachment of the

outer leaves, and that on a head of Iceberg type lettuce, wrapper leaves do not exceed 3 in

number.

§51.2526 Reasonably trimmed. 

"Reasonably trimmed" means that the butt is trimmed off closely below the point of attachment of

the outer leaves, and that on a head of Iceberg type lettuce, wrapper leaves do not exceed 12 in

number.

§51.2527 Cap leaf. 

"Cap leaf" is the first head leaf. This is the outermost leaf which fairly closely enfolds the compact

portion of the head, some portion of which extends to the top of the crown. The tip of the leaf

may be separated from the head, Provided, That the separation does not extend more than 1 1/4

inches (31.8 mm) in height from the compact portion of the head. (See figure 1.)

(a) All leaves outside of the cap leaf are wrapper leaves.

(b) On elongated or pointed heads the inner leaves that closely enfold the head three-fourths of

their length are head leaves.

§51.2528 Crown. 

"Crown" means the upper half of the head. (See figure 1.)

§51.2529 Injury. 

"Injury" means any specific defect described in §51.2534, Tables II and III, or an equally

objectionable variation of any one of these defects, any other defect, or any combination of

defects, which noticeably detracts from the appearance, or the edible or marketing quality of the

lettuce.

§51.2530 Damage. 

"Damage" means any specific defect described in §51.2534, Tables II and III, 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

lettuce.

§51.2531 Serious damage. 

"Serious damage" means any specific defect described in §51.2534, Tables II and III, or an

equally objectionable variation of any one of these defects, any other defect, or any combination

of defects, which seriously detracts from the appearance, or the edible or marketing quality of the

lettuce.

§51.2532 Permanent defects. 

"Permanent defects" means defects which are not subject to change during shipment or storage,

including but not limited to soft, burst, open or poorly trimmed heads, seedstems or dirt.
Shipping point, as used in these standards, means the point of origin of the shipment in the producing area or 2

at port of loading for ship stores for overseas shipment, or, in the case of shipments from outside the continental United

States, the port of entry into the United States.

7

§51.2533 Condition defects. 

"Condition defects" means defects which are subject to change during shipment or storage,

including but not limited to decay, tipburn, russet spotting, pink rib, rib discoloration, and freezing

injury.

§51.2534 Classification of defects. Table II -- At Shipping Point 2

Defect Injury Damage Serious damage

Tipburn More than 2 spots of Aggregate area of tipburn Aggregate area of tipburn

tipburn occurring occurring anywhere in the occurring anywhere in the

anywhere in the compact compact portion of the head compact portion of the head

portion of the head or exceeds a rectangle 1-inch (25.4 exceeds that of a rectangle 3-

the aggregate area of mm) in length and 1/2-inch (12.7 inches (76.2 mm) in length

discernible tipburn, mm) in width and 1-inch (25.4 mm) in

regardless of color, width. 

exceeds that of a

rectangle 1-inch (25.4

mm) in length and 1/4-

inch (6.4 mm) in width

Downy mildew Occurring on any head Readily apparent on any head Materially detracting from the

or wrapper leaf leaf; when mildew not appearance or shipping quality

accompanied by discoloration is of any head leaf; mildew not

readily apparent on more than 2 accompanied by discoloration

wrapper leaves, or discoloration is readily apparent on more

associated with mildew is readily than 3 wrapper leaves, or

apparent on any wrapper leaf discoloration associated with

mildew is readily apparent on

more than 2 wrapper leaves.

Opening In a hard or firm head when 1/4 or

more of the head is separated

from the remainder, or any degree

of opening in a fairly firm head 

Seedstems Excessively long, excessively Causing the head to split or

curved, tough or fibrous. (see when protruding through the

figures. 2 and 3) outer head leaves. 

Broken midribs More than 2 head leaves have More than 4 head leaves have

midribs broken in 2 due to midribs broken in 2 due to

abnormal growth abnormal growth. 

Russet spotting Present in any degree Present in any degree Present in any degree. 
8

Pink rib Occurring on any head Ribs of more than 2 head leaves Areas of deep pink color

leaf show areas of deep pink color seriously detracts from the

more than 2-inches (50.8 mm) in appearance or the edible

length or when causing more than quality of more than 2 head

2 head leaves to be excessively leaves. 

papery and tough

Rib discoloration Occurring on any head Aggregate length of brown or Seriously detracting from the

leaf black spots on outer surface of appearance or the edible

any head leaf exceeds 1 inch quality of more than 2 head

(25.4 mm)...... leaves.

Dirt Compact portion of the head is

smeared with mud, or wrapper

leaves are badly smeared with

mud, or when the basal portion is

caked with mud or dry dirt 

Insects and worms Compact portion of the head is Compact portion of the head is

infested, or the wrapper leaves are infested, or the wrapper leaves

badly infested with insects or are badly infested with insects

worms, or there is feeding injury or worms, or there is feeding

on the compact portion of the injury on more than 2 head

head leaves

Field Freezing Any peeling, feathering Peeling or feathering extends over

or yellow or brown more than 3/4 the area of the

discoloration resulting crown on more than 2 head leaves

from field freezing is or yellow or brown discoloration

readily apparent on any resulting from field freezing

outer head leaf extends over more than 1/2 of the

crown, or the wrapper leaves are

seriously damaged by

discoloration resulting from

freezing 

Discoloration Any 1 of the following Any 1 of the following types or a Any 1 of the following types,

(other than caused types or a combination combination of 2 or more types or a combination of 2 or more

by freezing) of 2 or more types the the seriousness of which exceeds types the seriousness of which

seriousness of which the maximum allowed for any 1 exceeds the maximum allowed

exceeds the maximum type for any 1 type. 

allowed for any 1 type

(1) Yellow or brown (1) Yellow or brown affecting any (1) Yellow or brown, affecting

discoloration from any portion of the leaf, or when any portion of the leaf, or very

cause affecting any seriously detracting from the seriously detracting from the

portion of the leaf, or appearance of the wrapper leaves appearance of the wrapper

when materially leaves

detracting from the

appearance of the

wrapper leaves
The color referred to is illustrated by plate 10 YR 8/4 in the Munsell Book of Color. Individual plates of the 4

above color may be purchased from the Munsell Color Co., 2441 North Calvert Street, Baltimore, Md. 21218. 

9

(2) Yellow or brown (2) Yellow or brown, materially (2) Yellow or brown,

discoloration from any detracting from the appearance of seriously detracting from the

cause when readily the head exclusive of the wrapper appearance of the head leaves

apparent on the compact leaves. exclusive of the wrapper

portion of the head....... leaves.......

(3) Discoloration (3) Discoloration following (3) Discoloration following

following bruising bruising materially detracting bruising seriously detracting

noticeably detracting from the appearance of more than from the appearance of more

from the appearance of 2 outer head leaves. than 2 outer head leaves 

more than 2 outer head

leaves

Table III -- (En Route or at Destination)

Defect Injury Damage Serious damage

Tipburn. Aggregate area of Aggregate area of tipburn of a Aggregate area of tipburn of a

tipburn of a light buff light buff or darker color light buff or darker color 4

or darker color exceeds occurring anywhere in the occurring anywhere in the

that of a rectangle 1 inch compact portion of the head compact portion of the head

(25.4 mm) in length and exceeds a rectangle 1 inch (25.4 exceeds that of a rectangle 3

1/4 inch (6.4 mm) in mm) in length and 1/2 inch (12.7 inches (78.2 mm) in length

width. mm) in width. and 1 inch (25.4 mm) in

4 4

width. 

Downy mildew. Any that is readily Materially detracting from the Materially detracting from the

apparent on any head appearance of any head leaf or appearance of more than 2

leaf or discoloration seriously detracting from the head leaves or seriously

associated with mildew appearance of more than 2 detracting from the

is readily apparent on wrapper leaves. appearance of the wrapper

more than 2 wrapper leaves. 

leaves.

Pink rib. More than 2 head leaves See Table II. See Table II. 

having midribs showing

noticeable areas of pink

color as viewed on the

outer surface of the leaf

or when causing any

head leaf to be

excessively papery and

tough.
10

Russet spotting. Present in any degree. Present in any degree on more The number, size, and color of

than 2 outer head leaves, or when the spots seriously detracts

the number, size, and color of the from the appearance of 2 or

spots materially detracts from the more head leaves. 

appearance of any head leaf.

Rib discoloration. Any distinct brown or See Table II See Table II.

black spots or rib

discoloration present on

the outer surface of any

head leaf.

Note: For classification of the following defects refer to Table II: opening, seedstems, broken midribs, field freezing,

discoloration, and dirt.
11

Figure 1
12

Figure 2 Figure 3