Code of Federal Regulations Title 7. Agriculture § 7.51.2128 Damage

(a) Chipped and scratched kernels, when the affected area on an individual kernel aggregates more than the equivalent of a circle one-quarter inch (6.4 mm) in diameter;

(b) Mold, when visible on the kernel, except when white or gray and easily rubbed off with the fingers;

(c) Gum, when a film of shiny, resinous appearing substance affects an area aggregating more than the equivalent of a circle one-quarter inch (6.4 mm) in diameter;

(d) Shriveling, when the kernel is excessively thin for its size, or when materially withered, shrunken, leathery, tough or only partially developed:  Provided, that partially developed kernels are not considered damaged if more than three-fourths of the pellicle is filled with meat;

(e) Brown spot on the kernel, either single or multiple, when the affected area aggregates more than the equivalent of a circle one-eighth inch (3.2 mm) in diameter;  and,

(f) Skin discoloration when more than one-half of the surface of the kernel is affected by very dark or black stains contrasting with the natural color of the skin.