Code of Federal Regulations Title 7. Agriculture § 7.51.1450 Serious damage

(a) Any plainly visible mold;

(b) Rancidity when the kernel is distinctly rancid to the taste. Staleness of flavor shall not be classed as rancidity;

(c) Decay affecting any portion of the kernel;

(d) Insects, web, or frass or any distinct evidence of insect feeding on the kernel;

(e) Internal discoloration which is dark gray, dark brown, or black and extends more than one-third the length of the half-kernel or piece;

(f) Adhering material from inside the shell when attached to more than one-half of the surface on one side of the half-kernel or piece;

(g) Dark kernel spots when more than three are on the kernel, or when any dark kernel spot or the aggregate of two or more spots affect an area of more than 10 percent of the surface of the half-kernel or piece;

(h) Dark skin discoloration, darker than “dark brown,” when covering more than one-fourth of the surface of the half-kernel or piece;  and,

(i) Undeveloped kernel. (See Figure 1.)