U.S. No. 1

• Potatoes that are graded U.S. No. 1 must have an attractive shape and overall appearance. They cannot have any discoloration and cannot be damaged in any way. These potatoes are typically sold to consumers in grocery stores or used in restaurant dishes that require aesthetically pleasing potatoes for a dish. Good-looking potatoes are usually needed when preparing them baked, steamed or boiled.

U.S. No. 2

• The USDA gives potatoes the U.S. No. 2 grade when they are bruised, misshapen or discolored. These potatoes are not typically sold to the public, but are sold to restaurants who need them for meals where the potato's appearance is not important. Such meals might include mashed potatoes or french fries, because the potato is peeled or thinly cut.

U.S. Commercial

• If a potato meets nearly all of the requirements for the U.S. No. 1 grade, but does not meet only a few, it may be designated a U.S. Commercial potato. For this grade to be given, the potato must be free from any extensive damage caused by dirt, foreign matter or Russet scab. The potato must also not suffer from Rhizoctonia, a common fungal disease.

External Defects

• The USDA gives a potato its grade based mostly on external defects. Such defects can include cracks, flattened areas or green patches. Damage caused by insects, rodents and birds is also considered. When examining these defects, they must be classified as "Damage" or "Serious Damage." Often, potatoes labeled "Serious Damage" are discarded.