The FDA law may not be as black a white as you wish. If the ingredient is present in small/incidental amounts and it does not have a techinical of functional effect in the final product, it does not need to be declared.
If you feel like your in for a headache or are not sure, just list everyting.
https://www.accessda....cfm?fr=101.100
(3) Incidental additives that are present in a food at insignificant levels and do not have any technical or functional effect in that food. For the purposes of this paragraph (a)(3), incidental additives are:
(i) Substances that have no technical or functional effect but are present in a food by reason of having been incorporated into the food as an ingredient of another food, in which the substance did have a functional or technical effect.
7. Is it necessary to declare ingredients in “trace”, i.e., incidental amounts? Can sulfites be considered incidental additives? Answer: FDA does not define “trace amounts”, however, there are some exemptions for declaring ingredients present in “incidental” amounts in a finished food. If an ingredient is present at an incidental level and has no functional or technical effect in the finished product, then it need not be declared on the label. An incidental additive is usually present because it is an ingredient of another ingredient. Note that major food allergens (as discussed on pages 20-24), regardless of whether they are present in the food in trace amounts, must be declared. Sulfites added to any food or to any ingredient in any food and that has no technical effect in that food are considered to be incidental only if present at less than 10 ppm. 21 CFR 101.100(a)(3) & (4)