21 CFR § 130.9 - Sulfites in standardized food.
(a) Any standardized food that contains a sulfiting agent or combination of sulfiting agents that is functional and provided for in the applicable standard or that is present in the finished food at a detectable level is misbranded unless the presence of the sulfiting agent or agents is declared on the label of the food. A detectable amount of sulfiting agent is 10 parts per million or more of the sulfite in the finished food. The level of sulfite in the finished food will be determined using sections 20.123 through 20.125, “Sulfurous Acid (Total) in Food Modified Monier-Williams Method Final Action” in “Official Methods of Analysis of the Association of Official Analytical Chemists,” 14th ed. (1984), which is incorporated by reference in accordance with 5 U.S.C. 552(a) and 1 CFR part 51, and the refinements of the “Total Sulfurous Acid” procedure in the “Monier-Williams Procedure (with Modifications) for Sulfites in Foods,” which is appendix A to part 101 of this chapter. A copy of sections 20.123 through 20.125 of the “Official Methods of Analysis of the Association of Official Analytical Chemists” is available from AOAC INTERNATIONAL, 481 North Frederick Ave., suite 500, Gaithersburg, MD 20877 , or available for at the National Archives and Records Administration (NARA). For information on the availability of this material at NARA, call 202-741-6030, or go to: http://www.archives.gov/federal_register/code_of_federal_regulations/ibr_locations.html.
(b) Any standardized food that, as a result of actions that are consistent with current good manufacturing practice, contains an indirectly added sulfiting agent that has no functional effect in the food and that would, in the absence of § 101.100(a)(4) of this chapter, be considered to be an incidental additive for purposes of § 130.8, conforms to the applicable definition and standard of identity if the presence of the sulfiting agent is declared on the label of the food.