Shotgun labeling is permitted under 21 C.F.R. 101.100(a)(1) and this Compliance Policy Guide (CPG) where variations in the items in each package normally occur in good packing practice.
The key language in the CPG is:
“…those ingredients common to all items should be listed first in the ingredient declaration followed by a listing of ingredients not common to all, including specific indications of which ingredients are actually present in designated articles.”
For more information please visit the FDA webpage on "Catch-All" or "Shotgun" Ingredients Declaration