Grades and grade requirements for corn.
Grade Minimum test weight per bushel (pounds) Maximum limits of:
Damaged kernels Broken corn and foreign material
(percent)
Heat damaged kernels Total
(percent) (percent)
U.S. No. 1 56.0 0.1 3.0 2.0
U.S. No. 2 54.0 0.2 5.0 3.0
U.S. No. 3 52.0 0.5 7.0 4.0
U.S. No. 4 49.0 1.0 10.0 5.0
U.S. No. 5 46.0 3.0 15.0 7.0
U.S. Sample Grade
U.S. Sample grade is corn that:
(a) Does not meet the requirements for the grades U.S. Nos. 1, 2, 3, 4, or 5; or
(b) Contains stones with an aggregate weight in excess of 0.1 percent of the sample
weight, 2 or more pieces of glass, 3 or more crotalaria seeds (Crotalaria spp.), 2 or more
castor beans (Ricinus communis L.), 4 or more particles of an unknown foreign
substance(s) or a commonly recognized harmful or toxic substance(s), 8 or more
cockleburs (Xanthium spp.), or similar seeds singly or in combination, or animal filth in
excess of 0.20 percent in 1,000 grams; or
(c) Has a musty, sour, or commercially objectionable foreign odor; or
(d) Is heating or otherwise of distinctly low quality.