21 CFR § 172.170 - Sodium nitrate.
(a) It is used or intended for use as follows:
(1) As a preservative and color fixative, with or without sodium nitrite, in smoked, cured sablefish, smoked, cured salmon, and smoked, cured shad, so that the level of sodium nitrate does not exceed 500 parts per million and the level of sodium nitrite does not exceed 200 parts per million in the finished product.
(2) As a preservative and color fixative, with or without sodium nitrite, in meat-curing preparations for the home curing of meat and meat products (including poultry and wild game), with directions for use which limit the amount of sodium nitrate to not more than 500 parts per million in the finished meat product and the amount of sodium nitrite to not more than 200 parts per million in the finished meat product.
(b) To assure safe use of the additive, in addition to the other information required by the Act:
(1) The label of the additive or of a mixture containing the additive shall bear:
(i) The name of the additive.
(ii) A statement of the concentration of the additive in any mixture.
(2) If in a retail package intended for household use, the label and labeling of the additive, or of a mixture containing the additive, shall bear adequate directions for use to provide a final food product that complies with the limitations prescribed in paragraph (a) of this section.
(3) If in a retail package intended for household use, the label of the additive or of a mixture containing the additive, shall bear the statement “Keep out of the reach of children”.