21 CFR 177: is this polymer cleared for this use?

FDA's page on determining the regulatory status of food contact components lists them: a regulation in 21 CFR (the indirect additive parts 174 to 178, including Part 177 for polymers), GRAS status, a prior sanction, a threshold of regulation exemption, or an effective FCN. The status of the finished material depends on every substance reasonably expected to migrate, not just the base resin.

Under 21 CFR 170.100, an FCN is effective only for the food contact substance made by the manufacturer or supplier named in it, for the stated intended use. Matching another firm's chemistry does not carry their FCN across.

FDA suggests reading each authorisation in three parts: the identity of the substance, its specifications such as purity or physical properties, and the limits on conditions of use. A Part 177 listing can restrict food types, temperatures or extractives.

21 CFR 170.39 lets FDA exempt a specific use of a substance when, among other conditions, it is not a known carcinogen and use results in dietary concentration at or below 0.5 parts per billion. FDA grants the exemption for a stated use; check FDA's list rather than assuming it applies to your material.

Customers often ask for a letter of guaranty or compliance statement. Keep each statement tied to the resin grade, supplier, revision and intended use.