Are the “secondary direct additives” listed in 21 CFR part 173 considered “food contact substances” as defined in section 409(h)(6) of the FD&C Act? Are facilities that manufacture/process, pack, or hold secondary direct additives required to register?

The answer to these questions depends upon the specific use of the secondary direct additive. The
regulations in 21 CFR part 173 stipulate the conditions of safe use for certain additives that are
added directly to food (such as enzyme preparations) as well as additives that are food contact
substances (such as ion exchange resins). A facility that manufactures/processes, packs, or holds
a substance approved in 21 CFR part 173 is exempt from registration only if the substance
satisfies the definition of “food contact substance” in section 409(h)(6) of the FD&C Act (21
U.S.C. 348(h)(6)). Otherwise, a facility that manufactures/processes, packs, or holds a substance
approved in 21 CFR part 173 is required to register.