U.S. Code of Federal Regulations
Regulations most recently checked for updates: Aug 27, 2025
§ 51.1541 - U.S. No. 1.
“U.S. No. 1” consists of potatoes which meet the following requirements:
(a) Similar varietal characteristics, except when designated as a mixed or specialty pack;
(b) Firm;
(c) Fairly clean;
(d) Fairly well shaped;
(e) Free from:
(1) Freezing;
(2) Blackheart;
(3) Late blight, southern bacterial wilt and ring rot; and,
(4) Soft rot and wet breakdown.
(f) Free from damage by any other cause. See §§ 51.1564 and 51.1565.
(g) Size. Not less than 1
(h) For tolerances see § 51.1546.
§ 51.1542 - U.S. Commercial.
“U.S. Commercial” consists of potatoes which meet the requirements of U.S. No. 1 grade except for the following:
(a) Free from serious damage caused by:
(1) Dirt or other foreign matter;
(2) Russet scab; and,
(3) Rhizoctonia.
(b) Increased tolerances for defects specified in § 51.1546.
§ 51.1543 - U.S. No. 2.
“U.S. No. 2” consists of potatoes which meet the following requirements:
(a) Similar varietal characteristics, except when designated as a mixed or specialty pack;
(b) Not seriously misshapen;
(c) Free from:
(1) Freezing;
(2) Blackheart;
(3) Late blight, southern bacterial wilt and ring rot; and,
(4) Soft rot and wet breakdown.
(d) Free from serious damage by any other cause. See §§ 51.1564 and 51.1565.
(e) Size. Not less than 1
(f) For tolerances see § 51.1546.
§ 51.1545 - Size.
(a) The minimum size, or minimum and maximum sizes may be specified in connection with the grade in terms of diameter or weight of the individual potato, or in accordance with one of the size designations in Table I or Table II: Provided, That sizes so specified shall not be in conflict with the basic size requirements for the grade.
(b) When size is designated as shown in Table II, the corresponding weight ranges shall apply. These size designations may be applied to potatoes packed in any size container: Provided, that the weight ranges are within the limits specified.
Table 1
| Size designation | Minimum diameter
1
or weight | Maximum diameter
1
or weight | ||
|---|---|---|---|---|
| Inches | Ounces | Inches | Ounces | |
| Creamer |
| ( 3) | 1
| ( 3) |
| Chef | 2
| 8 | 4
| 28 |
| Size A 2 | 1
| ( 3) | ( 3) | ( 3) |
| Size B | 1
| ( 3) | 2
| ( 3) |
| Small | 1
| ( 3) | 2
| 6 |
| Medium | 2
| 5 | 3
| 10 |
| Large | 3 | 10 | 4
| 28 |
1 Diameter means the greatest dimension at right angles to the longitudinal axis, without regard to the position of the stem end.
2 In addition to the minimum size specified, a lot of potatoes designated as Size A shall contain at least 40 percent of potatoes which are 2
3 No requirement.
Table II
[Ounces]
| Size designation | Minimum weight | Maximum weight |
|---|---|---|
| Under 50 | 15 | |
| 50 | 12 | 19 |
| 60 | 10 | 16 |
| 70 | 9 | 15 |
| 80 | 8 | 13 |
| 90 | 7 | 12 |
| 100 | 6 | 10 |
| 110 | 5 | 9 |
| 120 | 4 | 8 |
| 130 | 4 | 8 |
| 140 | 4 | 8 |
| Over 140 | 4 | 8 |
§ 51.1546 - Tolerances.
To allow for variations incident to proper grading and handling in each of the foregoing grades, the following tolerances by weight or equivalent basis, are provided as specified.
(a) For defects—(1) U.S. No. 1. (i) At Shipping Point: A total of 8 percent for potatoes in any lot which fail to meet the requirements for the grade: Provided, That included in this tolerance not more than the following percentages shall be allowed for the defects listed:
(A) 5 percent for external defects;
(B) 5 percent for internal defects; and
(C) Not more than a total of 1 percent for potatoes which are frozen or affected by soft rot or wet breakdown. See § 51.1547.
(ii) En route or at destination: A total of 10 percent for potatoes in any lot which fail to meet the requirements for the grade: Provided, That included in this tolerance not more than a total of 8 percent shall be allowed for permanent defects: And provided further, the following percentages shall be allowed for the defects listed:
(A) 7 percent for external defects, including therein not more than 5 percent for permanent external defects;
(B) 7 percent for internal defects, including therein not more than 5 percent for permanent internal defects; and
(C) Not more than a total of 2 percent for potatoes which are frozen or affected by soft rot or wet breakdown. See § 51.1547.
(2) U.S. Commercial: A total of 20 percent for potatoes in any lot which fail to meet the requirements for the grade: Provided, That included in this tolerance not more than the following percentages shall be allowed for the defects listed:
(i) 10 percent for potatoes which fail to meet the requirements for U.S. No. 2 grade, including therein not more than:
(ii) 6 percent for external defects;
(iii) 6 percent for internal defects; and
(iv) Not more than a total of 1 percent for potatoes which are frozen or affected by soft rot or wet breakdown. See § 51.1547.
(3) U.S. No. 2. (i) At Shipping Point: A total of 10 percent for potatoes in any lot which fail to meet the requirements for the grade: Provided, That included in this tolerance not more than the following percentages shall be allowed for the defects listed:
(A) 6 percent for external defects;
(B) 6 percent for internal defects; and
(C) Not more than a total of 1 percent for potatoes which are frozen or affected by soft rot or wet breakdown. See § 51.1547.
(ii) En route or at destination: A total of 12 percent for potatoes in any lot which fail to meet the requirements for the grade: Provided, That included in this tolerance not more than a total of 10 percent shall be allowed for permanent defects: And provided further, the following percentages shall be allowed for the defects listed:
(A) 8 percent for external defects, including therein not more than 6 percent for permanent external defects;
(B) 8 percent for internal defects, including therein not more than 6 percent for permanent internal defects; and
(C) Not more than a total of 2 percent for potatoes which are frozen or affected by soft rot or wet breakdown. See § 51.1547.
(b) For off-size. (1) Not more than 3 percent of the potatoes in any lot may be smaller than the required or specified minimum size except that a tolerance of 5 percent shall be allowed for potatoes packed to meet a minimum size of 2
(2) When a percentage of the potatoes is specified to be of a certain size and larger, individual samples shall have not less than one-half of the percentage specified: Provided, That the average for the entire lot is not less than the percentage specified.
§ 51.1547 - Application of tolerances.
Individual samples shall have not more than double the tolerances specified, except that at least one defective and one off-size potato may be permitted in any sample: Provided, That en route or at destination one-tenth of the samples may contain three times the tolerance permitted for potatoes which are frozen or affected by soft rot or wet breakdown: And provided further, That the averages for the entire lot are within the tolerances specified for the grade.
§ 51.1548 - Samples for grade and size determination.
Individual samples shall consist of at least 20 pounds. When individual packages contain at least 20 pounds, each individual sample is drawn from one package; when packages contain less than 20 pounds, a sufficient number of adjoining packages are opened to provide at least a 20-pound sample. The number of such individual samples drawn for grade and size determination will vary with the size of the lot.
§ 51.1549 - Skinning.
(a) The following definitions provide a basis for describing lots of potatoes as to the degree of skinning whenever description may be appropriate:
(1) “Practically no skinning” means that not more than 5 percent of the potatoes in the lot have more than one-tenth of the skin missing or “feathered”;
(2) “Slightly skinned” means that not more than 10 percent of the potatoes in the lot have more than one-fourth of the skin missing or “feathered”;
(3) “Moderately skinned” means that not more than 10 percent of the potatoes in the lot have more than one-half of the skin missing or “feathered”; and
(4) “Badly skinned” means that more than 10 percent of the potatoes in the lot have more than one-half of the skin missing or “feathered”.
§ 51.1550 - Similar varietal characteristics.
Similar varietal characteristics means that the potatoes in any lot have the same general shape, color and character of skin, and color of flesh.
§ 51.1552 - Clean.
Clean means that at least 90 percent of the potatoes in any lot are practically free from dirt or staining and practically no loose dirt or other foreign matter is present in the container.
§ 51.1553 - Fairly clean.
Fairly clean means that at least 90 percent of the potatoes in any lot are reasonably free from dirt or staining and not more than a slight amount of loose dirt or foreign matter is present in the container.
§ 51.1554 - Mature.
Mature means that the skins of the potatoes are generally firmly set and not more than 5 percent of the potatoes in the lot have more than one-tenth of the skin missing or “feathered.”
§ 51.1555 - Fairly well matured.
Fairly well matured means that the skins of the potatoes are generally fairly firmly set and not more than 10 percent of the potatoes in the lot have more than one-fourth of the skin missing or “feathered.”
§ 51.1557 - Fairly well shaped.
Fairly well shaped means that the potato is not materially pointed, dumbbell-shaped or otherwise materially deformed.
§ 51.1558 - Seriously misshapen.
Seriously misshapen means that the potato is seriously pointed, dumbell-shaped or otherwise badly deformed.
§ 51.1560 - Damage.
“Damage” means any defect, or any combination of defects, which materially detracts from the edible or marketing quality, or the internal or external appearance of the potato, or any external defect which cannot be removed without a loss of more than 5 percent of the total weight of the potato. See Tables III, IV, V and VI in § 51.1564 and Table VII in § 51.1565.
§ 51.1561 - Serious damage.
“Serious damage” means any defect, or any combination of defects, which seriously detracts from the edible or marketing quality, or the internal or external appearance of the potato, or any external defect which cannot be removed without a loss of more than 10 percent of the total weight of the potato. See Tables III, IV, V and VI in § 51.1564 and Table VII in 5§ 1.1565.
§ 51.1562 - Freezing.
Freezing means that the potato is frozen or shows evidence of having been frozen.
§ 51.1563 - Soft rot or wet breakdown.
Soft rot or wet breakdown means any soft, mushy, or leaky condition of the tissue such as slimy soft rot, leak, or wet breakdown following freezing injury.
§ 51.1564 - External defects.
External defects are defects which can be detected externally. However, cutting may be required to determine the extent of the injury. Some external defects are listed in Tables III, IV, V and VI.
Table III—External Defects
| Defects | Damage | Serious damage 1 |
|---|---|---|
| Air Cracks | When removal causes a loss of more than 5 percent of the total weight of the potato or when the air crack(s) affects more than
| When removal causes a loss of more than 10 percent of the total weight of the potato or when the air crack(s) affects more than
|
| Artificial Coloring | When unsightly or when concealing any defect causing damage or when penetrating the flesh and removal causes loss of more than 5 percent of total weight of potato | When concealing a serious defect or when penetrating into the flesh and removal causes loss of more than 10 percent of total weight of potato. |
| Bruises (Not including pressure bruise and sunken discolored areas) | When removal causes a loss of more than 5 percent of the total weight of the potato or when the area affected is more than 5 percent of the surface in the aggregate (i.e.,
| When removal causes a loss of more than 10 percent of the total weight of the potato or when the area affected is more than 10 percent of the surface in the aggregate (i.e., 1
|
| Cuts | When one smooth cut affects more than 5 percent of the surface area | Cut(s) that affect more than 10 percent of the surface area in the aggregate or when a single side cut extends beyond
|
| Dirt | When materially detracting from the appearance of the potato | When seriously detracting from the appearance of the potato. |
| Elephant Hide | When affecting over 10 percent of the surface area of the potato | When affecting over 25 percent of the surface area. |
| Enlarged Lenticels | When materially detracting from the appearance of the potato | When seriously detracting from the appearance of the potato. |
| External Discoloration (Areas that are light tan or lighter in color and blends should be ignored) | When more than 30 percent of the surface is affected by light tan or light brown colors which do not blend or when more than 15 percent of the surface is affected by colors darker than light tan or light brown | When more than 60 percent of the surface is affected by light tan or light brown colors which do not blend or when more than 30 percent of the surface is affected by colors darker than light tan or light brown. |
| Flattened or Depressed Areas/Pressure Bruises | When removal of underlying discolored flesh causes a loss of more than 5 percent of the total weight of the potato or when the flattened or depressed area(s) covers more surface area than allowed in Table IV. (See Table IV.) | When removal of underlying discolored flesh the causes a loss of more than 10 percent of the weight of the potato or when the flattened depressed area(s) covers more surface area than allowed in the Table IV. (See Table IV.) |
| Flea Beetle Injury | When materially detracting from the appearance or when removal causes a loss of more than 5 percent of the total weight of the potato or when the area affected is more than 5 percent of the surface in the aggregate | When seriously detracting from the appearance of the potato or when removal causes a loss of more than 10 percent of the weight of the potato or when the area affected is more than 10 percent of the surface in the aggregate. |
| Greening | When removal causes a loss of more than 5 percent of the total weight of the potato or when green color affects more than 25 percent of the surface in the aggregate | When removal causes a loss of more than 10 percent of the weight of the potato or when green color affects more than 50 percent of the surface in the aggregate. |
| Growth Cracks | When the growth crack(s) affects more than
| When the growth crack(s) affects more than
|
| Grub Damage | When removal causes a loss of more than 5 percent of the total weight of the potato or when affecting more than 5 percent of the surface area (i.e. more than
| When removal causes a loss of more than 10 percent of the total weight of the potato or when affecting more than 10 percent of the surface area (i.e. more than 1
|
| Insects or Worms | (See Serious Damage.) | When present inside the potato. |
| Nematode (Root Knot) | When removal causes loss of more than 5 percent of total weight of potato | When removal causes loss of more than 10 percent of total weight of potato. |
| Rhizoctonia | When affecting more than 15 percent of the surface in the aggregate | When affecting more than 50 percent of the surface in the aggregate. |
| Russeting (On Non Russet Type) | When more than 50 percent of the surface is affected in the aggregate | N/A. |
| Rodent or Bird Damage | When removal causes a loss of more than 5 percent of the total weight of the potato or when affecting more than 5 percent of the surface area (i.e. more than
| When removal causes a loss of more than 10 percent of the total weight of the potato or when affecting more than 10 percent of the surface area (i.e. more than 1
|
| Scab, Pitted | When removal causes a loss of more than 5 percent of the total weight of the potato or when scab affects an aggregate area of more than
| When the removal causes a loss of more than 10 percent of the total weight of the potato or when scab affects an aggregate area of more than 1 inch. (Based on a potato 2
|
| Scab, Russet | Smooth and affecting more than
| Rough and affecting more than 25 percent of the surface in the aggregate. |
| Scab, Surface | When more than 5 percent of the surface in the aggregate is affected | When more than 25 percent of the surface in the aggregate is affected. |
| Second Growth | When materially detracting from the appearance of the potato | When seriously detracting from the appearance of the potato. |
| Silver Scurf | When affecting more than 50 percent of the surface area of the potato | When its severity causes a wrinkling of the skin over more than 50 percent of the surface. |
| Sprouts | When more than 5 percent of the potatoes in any lot have any sprout more than
| When more than 10 percent of the potatoes in any lot have any sprout more than
|
| Sunburn | When removal causes loss of more than 5 percent of total weight of potato | When removal causes loss more than 10 percent of total weight of potato. |
| Sunken Discolored Areas | SEE TABLE VI | SEE TABLE VI. |
| Surface Cracks (Areas affected by fine net-like cracking should be ignored.) | When smooth shallow cracking affects more than
| When rough deep cracking affects more than 10 percent of the surface. |
| Wireworm or Grass Damage | When affecting the flesh of the potato and removal causes loss of more than 5 percent of total weight of potato. | When affecting the flesh of the potato and removal causes loss of more than 10 percent of total weight of potato. |
The following defects are considered serious damage when present in any degree: 1. Freezing. 2. Late blight. 3. Ring rot. 4. Southern bacterial wilt. 5. Soft rot. 6. Wet breakdown.
Table IV—Flattened or Depressed Areas—Pressure Bruises Maximum Area Allowed
| Diameter | Weight | No. 1
(aggregate area) | No. 2
(aggregate area) |
|---|---|---|---|
| Potato is: | Potato is: | Not more than: | Not more than: |
| Less than 2 in | Less than 4 oz |
| 1 in |
| 2 to 2
| 4 to 6 oz | 1 in | 1
|
| More than 2
| More than 6 to 8 oz | 1
| 1
|
| More than 3 to 3
| More than 8 to 14 oz | 1
| 1
|
| More than 3
| More than 14 to 20 oz | 1
| 2 in |
| More than 4 to 4
| More than 20 to 28 oz | 2 in | 2
|
| More than 4
| More than 28 to 36 oz | 2
| 2
|
| More than 5 in | More than 36 oz | 2
| 3
|
Table V—Depth Allowed for Growth Cracks
| Diameter | Weight | No. 1
(depth) | No. 2
(depth) |
|---|---|---|---|
| Potato is: | Potato is: | Not more than: | Not more than: |
| Less than 2 in | Less than 4 oz |
|
|
| 2 to 2
| 4 oz to 6 oz |
|
|
| More than 2
| More than 6 oz to 8 oz |
|
|
| More than 3 in | More than 8 oz |
|
|
Table VI—Sunken Discolored Areas Maximum Area Allowed
| Diameter | Weight | No. 1
(aggregate area) | No. 2
(aggregate area) |
|---|---|---|---|
| Potato is: | Potato is: | Not more than: | Not more than: |
| Less than 2 in | Less than 4 oz |
|
|
| 2 to 2
| 4 to 6 oz |
| 1 in |
| More than 2
| More than 6 to 8 oz | 1 in | 1
|
| More than 3 to 3
| More than 8 to 14 oz | 1
| 1
|
| More than 3
| More than 14 to 20 oz | 1
| 1
|
| More than 4 to 4
| More than 20 to 28 oz | 1
| 2 in |
| More than 4
| More than 28 to 36 oz | 2 in | 2
|
| More than 5 in | More than 36 oz | 2
| 2
|
§ 51.1565 - Internal defects.
Internal defects are defects which cannot be detected without cutting the potato. Some internal defects are listed in Table VII.
Table VII—Internal Defects
| Defects | Damage Maximum Allowed | Serious Damage Maximum Allowed |
|---|---|---|
| Ingrown Sprouts, Internal Discoloration, Vascular Browning, Fusarium Wilt, Net Necrosis, Other Necrosis, Stem End Browning | 5 percent waste | 10 percent waste. |
| Internal Black Spot | When the spot(s) are darker than the official color chip (POT-CC-2) after removing 5 percent of the total weight of the potato | When the spot(s) are darker than the official color chip (POT-CC-2) after removing 10 percent of the total weight of the potato. |
| Hollow Heart or Hollow Heart with Discoloration | Area affected not to exceed that of a circle
| Area affected not to exceed that of a circle
|
| Light Brown Discoloration (Brown Center) | Area affected not to exceed that of a circle
| Area affected not to exceed that of a circle
|
| Internal Brown Spot and Similar Discoloration (Heat Necrosis) | Not more than the equivalent of 3 scattered spots
| Not more than the equivalent of 6 scattered spots
|
1Note: Correspondingly lesser or greater areas in smaller or larger potatoes.
§ 51.1566 - Metric conversion table.
| Inches | Millimeters (mm) |
|---|---|
|
| 3.2 |
|
| 6.4 |
|
| 12.7 |
|
| 19.1 |
| 1 equals | 25.4 |
| 1
| 38.1 |
| 2 equals | 50.8 |
| 2
| 63.5 |
| 3 equals | 76.2 |
| 3
| 88.9 |
| 4 equals | 101.6 |
| 4
| 114.3 |
| Ounces | Grams |
|---|---|
| 1 equals | 28.35 |
| 4 equals | 113.40 |
| 5 equals | 141.75 |
| 6 equals | 170.10 |
| 7 equals | 198.45 |
| 8 equals | 226.80 |
| 9 equals | 255.15 |
| 10 equals | 283.50 |
| 12 equals | 340.20 |
| 14 equals | 396.90 |
| 16 equals | 453.60 |
| 18 equals | 510.30 |
| 19 equals | 538.60 |
| 20 equals | 567.00 |
