21 C.F.R. § 170.240
Part 4 of a GRAS notice: Self-limiting levels of use
In circumstances where the amount of the notified substance that can be added to food is limited because food containing levels of the notified substance above a particular level would become unpalatable or technologically impractical, in Part 4 of your GRAS notice you must include data and information on such self-limiting levels of use.