7 CFR § 51.3411
Usable piece
July 6, 2020
“Usable Piece” means that portion of the potato remaining after trimming, or as it occurs in the sample:
(a) Not have any unusable material;
(b) Unless otherwise specified, weigh at least 4 ounces; and,
(c) Must have at least 50% of peel remaining after trimming.