United States

Department of

Agriculture

Agricultural 

Marketing

Service

Fruit and

Vegetable

Programs

Fresh

Products

Branch

United States Standards

for Grades of

Lettuce

Effective December 1, 1975

(Reprinted - January 1997)
1

Packing of the product in conformity with the requirements 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

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.

Grades 
2

§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.

(e) For tolerances see §51.2513.

Tolerances 
2 Shipping point, as used in these standards, means the point of origin of the shipment in producing area or

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

United States, the port of entry into the United States.

3

§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.2 8 percent for heads of lettuce which fail to

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.2

 8 percent for heads of lettuce which fail to

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.2

 8 percent for heads of lettuce which fail to

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

percentages shall be allowed for defects listed:
4

(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,

 percent

Total number of heads in package

24 18 or 20 30 Over 30

1 1 12 2

3 3 23 4

4 3 34 4

5 3 34 5

6 4 35 6

8 5 46 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 36° F (2.2 ° 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 approximate 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.

(i) The standard size head for a 2 dozen pack is that size head, having 4 wrapper leaves, which
3 The color referred to is illustrated by plate 5 GY 8/6 in the Munsell Book of Color. Individual plates of

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

5

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.

§51.2523 Doubles. 
6

"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.

§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
2 Shipping point, as used in these standards, means the point of origin of the shipment in the producing area

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

United States, the port of entry into the United States.

7

freezing injury.

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

Defect Injury Damage Serious damage

Tipburn More than 2 spots of

tipburn occurring

anywhere in the

compact portion of the

head or the aggregate

area of discernible

tipburn, regardless of

color, exceeds that of a

rectangle 1-inch (25.4

mm) in length and 1/4-

inch (6.4 mm) in width

Aggregate area of tipburn

occurring anywhere in the

compact portion of the head

exceeds a rectangle 1-inch (25.4

mm) in length and 1/2-inch (12.7

mm) in width

Aggregate area of tipburn

occurring anywhere in the

compact portion of the head

exceeds that of a rectangle 3-

inches (76.2 mm) in length

and 1-inch (25.4 mm) in

width. 

Downy mildew Occurring on any head

or wrapper leaf

Readily apparent on any head

leaf; when mildew not

accompanied by discoloration is

readily apparent on more than 2

wrapper leaves, or discoloration

associated with mildew is readily

apparent on any wrapper leaf

Materially detracting from

the appearance or shipping

quality of any head leaf;

mildew not accompanied by

discoloration is readily

apparent on more than 3

wrapper leaves, or

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

curved, tough or fibrous. (see

figures. 2 and 3)

Causing the head to split or

when protruding through the

outer head leaves. 

Broken midribs More than 2 head leaves have

midribs broken in 2 due to

abnormal growth

More than 4 head leaves have

midribs broken in 2 due to

abnormal growth. 

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

Pink rib Occurring on any head

leaf

Ribs of more than 2 head leaves

show areas of deep pink color

more than 2-inches (50.8 mm) in

length or when causing more

than 2 head leaves to be

excessively papery and tough

Areas of deep pink color

seriously detracts from the

appearance or the edible

quality of more than 2 head

leaves. 

Rib discoloration Occurring on any head

leaf

Aggregate length of brown or

black spots on outer surface of

any head leaf exceeds 1 inch

(25.4 mm)......

Seriously detracting from the

appearance or the edible

quality of more than 2 head

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

infested, or the wrapper leaves

are badly infested with insects or

worms, or there is feeding injury

on the compact portion of the

head

Compact portion of the head

is infested, or the wrapper

leaves are badly infested with

insects or worms, or there is

feeding injury on more than 2

head leaves

Field Freezing Any peeling, feathering

or yellow or brown

discoloration resulting

from field freezing is

readily apparent on any

outer head leaf

Peeling or feathering extends

over more than 3/4 the area of

the crown on more than 2 head

leaves or yellow or brown

discoloration resulting from field

freezing extends over more than

1/2 of the crown, or the wrapper

leaves are seriously damaged by

discoloration resulting from

freezing 

Discoloration

(other than caused

by freezing)

Any 1 of the following

types or a combination

of 2 or more types the

seriousness of which

exceeds the maximum

allowed for any 1 type

Any 1 of the following types or a

combination of 2 or more types

the seriousness of which exceeds

the maximum allowed for any 1

type

Any 1 of the following types,

or a combination of 2 or more

types the seriousness of

which exceeds the maximum

allowed for any 1 type. 

(1) Yellow or brown

discoloration from any

cause affecting any

portion of the leaf, or

when materially

detracting from the

appearance of the

wrapper leaves

(1) Yellow or brown affecting

any portion of the leaf, or when

seriously detracting from the

appearance of the wrapper leaves

(1) Yellow or brown,

affecting any portion of the

leaf, or very seriously

detracting from the

appearance of the wrapper

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

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

9

(2) Yellow or brown

discoloration from any

cause when readily

apparent on the

compact portion of the

head.......

(2) Yellow or brown, materially

detracting from the appearance

of the head exclusive of the

wrapper leaves.

(2) Yellow or brown,

seriously detracting from the

appearance of the head leaves

exclusive of the wrapper

leaves.......

(3) Discoloration

following bruising

noticeably detracting

from the appearance of

more than 2 outer head

leaves

(3) Discoloration following

bruising materially detracting

from the appearance of more

than 2 outer head leaves.

(3) Discoloration following

bruising seriously detracting

from the appearance of more

than 2 outer head leaves 

Table III -- (En Route or at Destination)

Defect Injury Damage Serious damage

Tipburn. Aggregate area of

tipburn of a light buff 4

or darker color exceeds

that of a rectangle 1

inch (25.4 mm) in

length and 1/4 inch (6.4

mm) in width.

Aggregate area of tipburn of a

light buff 4

 or darker color

occurring anywhere in the

compact portion of the head

exceeds a rectangle 1 inch (25.4

mm) in length and 1/2 inch

(12.7 mm) in width.

Aggregate area of tipburn of

a light buff 4

 or darker color

occurring anywhere in the

compact portion of the head

exceeds that of a rectangle 3

inches (78.2 mm) in length

and 1 inch (25.4 mm) in

width. 

Downy mildew. Any that is readily

apparent on any head

leaf or discoloration

associated with mildew

is readily apparent on

more than 2 wrapper

leaves.

Materially detracting from the

appearance of any head leaf or

seriously detracting from the

appearance of more than 2

wrapper leaves.

Materially detracting from

the appearance of more than

2 head leaves or seriously

detracting from the

appearance of the wrapper

leaves. 

Pink rib. More than 2 head

leaves 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.

See Table II. See Table II. 
10

Russet spotting. Present in any degree. Present in any degree on more

than 2 outer head leaves, or

when the number, size, and color

of the spots materially detracts

from the appearance of any head

leaf.

The number, size, and color

of the spots seriously detracts

from the appearance of 2 or

more head leaves. 

Rib discoloration. Any distinct brown or

black spots or rib

discoloration present on

the outer surface of any

head leaf.

See Table II See Table II.

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