``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; \2\---------------------------------------------------------------------------
\2\ Potatoes in containers bearing official State Seed Certification Tags and Seals are not required to be fairly clean but shall be free from damage by dirt.---------------------------------------------------------------------------
(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 Sec. Sec. 51.1564 and 51.1565.
(g) Size. Not less than 1\7/8\ inches in diameter, unless otherwise specified in connection with the grade.
(h) For tolerances see Sec. 51.1546. [35 FR 18258, Dec. 1, 1970, as amended at 76 FR 31789, June 2, 2011]