§ Grades and grade requirements for sunflower seed. Grade Minimum test weight per bushel (pounds) Maximum limits of— Damaged Sunflower Seed Heat Damaged (percent) Total (Percent) Dehulled seed (percent) U.S. No. 1 25.0 0.5 5.0 5.0 U.S. No. 2 25.0 1.0 10.0 5.0 U.S. Sample grade— U.S. Sample grade is sunflower seed that: (a) Does not meet the requirements for the grades U.S. Nos. 1 or 2; or (b) Contains 8 or more stones which have an aggregate weight in excess of 0.20 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), 10 or more rodent pellets, bird droppings, or equivalent quantity of other animal filth per 600 grams of sunflower seed; or (c) Has a musty, sour, or commercially objectionable foreign odor; or (d) Is heating or otherwise of distinctly low quality.