food may not contain unapproved additives or additives that exceed the amounts specified in 21 C.F.R. 170-180 relating to food additives, generally recognized as safe or prior sanctioned substances that exceed amounts specified in 21 C.F.R. 181-186, substances that exceed amounts specified in 9 C.F.R., Subpart C, Section 424.21(b) Food Ingredients and Sources of Radiation, or pesticide residues that exceed provisions specified in 40 C.F.R. 180 Tolerances for Pesticides Chemicals in Food, and exceptions.