Potatoes of each of these grades shall be of one variety or similar varietal characteristics which are fairly well shaped, fairly clean, free from freezing injury, blackheart, late blight, and soft rot or wet breakdown, and from damage caused by sunburn, second growth, growth cracks, air cracks, hollowheart, internal discoloration, cuts, shriveling, sprouting, scab, dry rot, rhizoctonia, other diseases, wireworm, other insects, or mechanical or other means. Potatoes of these grades shall also be mature: Provided, That potatoes which are not mature and the outer skin loosens or “feathers” readily under the usual handling practices need not meet this requirement if they are firm and are further designated as “Early” in connection with the grade, as for example “U.S. Grade A Medium-Early.” Potatoes on the shown face shall be reasonably representative in size and quality of the contents of the containers. (See §51.5177.)

(a) Tolerances. Incident to proper grading and handling, except for the tolerances for size, not more than a total of 5 percent, by weight, of the potatoes in any lot may fail to meet the requirements of the grade, including not more than 1 percent for potatoes affected by soft rot or wet breakdown. (See §51.1579.)