United States

Department of

Agriculture

Agricultural 

Marketing

Service

Fruit and

Vegetable

Division

Fresh

Products

Branch

United States Standards

for Grades of

Sweetpotatoes for Canning

or Freezing

Effective July 24, 1959

(Reprinted - January 1997)
 Compliance with the provisions of these standards shall not excuse failure to comply with the provisions of the 1

Federal Food, Drug and Cosmetic Act, or with applicable State laws and regulations.

1

United States Standards for Grades of Sweetpotatoes

 for Canning or Freezing 1

Grades 

51.1660 U.S. No. 1.

Culls

51.1661 Culls.

Application of Standards

51.1662 Application of standards.

Definitions

51.1663 Similar type.

51.1664 Reasonably firm.

51.1665 Fairly well shaped.

51.1666 Fairly well colored.

51.1667 Damage.

51.1668 Usable piece.

51.1669 Cull material.

51.1670 Diameter.

51.1671 Length.

Grade 

§51.1660 U.S. No. 1. 

"U.S. No. 1'' consists of sweetpotatoes of similar type which are reasonably firm, fairly well

shaped, fairly well colored and which are free from soft rot, black rot, freezing injury, scald, cork

or other internal discoloration, cull material and which are free from damage caused by dry rot

other than black rot, other diseases, bruises, cuts, growth cracks, pithiness, stringiness, sunburn,

insects, mechanical or other means. 

(a) Unless otherwise specified, the diameter of each sweetpotato or usable piece shall be not less

than 1 inch nor more than 2-1/4 inches, and the length shall be not less than 2 inches nor more

than 7 inches. 

(b) Tolerances for off-size: 15 percent, by weight, for sweetpotatoes in any lot which fail to meet

the length and diameter requirements, including therein not more than the following amounts: 

(1) 3 percent for sweetpotatoes which are smaller than the specified minimum diameter; 

(2) 10 percent for sweetpotatoes which are larger than the specified maximum diameter; 

(3) 5 percent for sweetpotatoes which are shorter than the specified minimum length; and, 

(4) 10 percent for sweetpotatoes which are longer than the specified maximum length. 

Culls 

§51.1661 Culls. 
2

"Culls'' consist of sweetpotatoes which fail to meet the requirements of the foregoing grade other

than for size. 

Application of Standards 

§51.1662 Application of standards. 

In the application of this grade to determine the percentage of the lot which meets the

requirements of the U.S. No. 1 grade, tolerances shall not apply, except for size. (See

§51.1660(b).) 

(a) Tolerances. When a lot of sweetpotatoes is required to meet the U.S. No. 1 grade, the

following tolerances, by weight, shall apply: 

(1) For defects. 10 percent for sweetpotatoes which fail to meet the requirements of the grade

other than for off-size and cull material: Provided, That not more than one-fifth of this amount,

or 2 percent, shall be allowed for sweetpotatoes affected by soft rot or black rot; and, 

(2) For cull material. 5 percent. 

Definitions 

§51.1663 Similar type. 

"Similar type" means that each sweetpotato has the same character of flesh and the same general

color of flesh as other sweetpotatoes in the lot. For example, dry type and moist type shall not be

mixed, and white-fleshed and yellow or orange-fleshed varieties shall not be mixed. 

§51.1664 Reasonably firm. 

"Reasonably firm" means that the sweetpotato is not soft, flabby or more than slightly shriveled. 

§51.1665 Fairly well shaped.

"Fairly well shaped" means that the sweetpotato is not so curved, crooked, grooved, constricted,

flattened or otherwise misshapen that one or more usable pieces cannot be obtained from the

potato. 

§51.1666 Fairly well colored.

"Fairly well colored" means that sweetpotatoes of the white-fleshed varieties shall be no lighter in

color than a light straw color, and that yellow or orange-fleshed varieties shall be no lighter in

color than a light salmon-orange color. 

§51.1667 Damage. 

"Damage" means any defect which materially affects the canning quality, and which cannot be

removed in the ordinary process of trimming without a loss of more than 5 percent of the total

weight of the sweetpotato, excluding peel covering the defective area. 

§51.1668 Usable piece. 

"Usable piece" means a portion of the sweetpotato which meets the requirement of the specified

minimum length, and which when processed will have essentially the appearance of a whole

sweetpotato. 

§51.1669 Cull material. 

"Cull material" means pieces other than usable pieces of sweetpotatoes, vines, root crowns,

sprouts, secondary rootlets, loose dirt, adhering caked dirt or other foreign matter. 

§51.1670 Diameter.

"Diameter" means the greatest dimension of the sweetpotato, or usable piece, measured at right

angles to the longitudinal axis. 
3

§51.1671 Length.

"Length" means the dimension of the sweetpotato, or usable piece, measured in a straight line

between points at or near each end of the sweetpotato where it is at least five-eighths inch in

diameter. 
4

SHAPE - FAIRLY WELL SHAPED

One usable piece available

Illustration SPOPR 1
5

SHAPE - FAIRLY WELL SHAPED

One or more usable pieces available

(Pieces shown)

Illustration SPOPR 2
6

SHAPE - NOT FAIRLY WELL SHAPED

No usable piece available

Illustration SPOPR 3