Fluoride Limits

Fluoride Limits (Guideline) The Committee on Food Chemicals Codex has established limits for fluoride in numerous monographs. For phosphates, this reflects the natural occurrence of fluoride in the inorganic phosphate starting material. Fluoride limits in other monographs may reflect the natural occurrence of fluoride in the article or in reagents... 

Following issuance of the Fluoride Limits (Guideline) in earlier editions of the Food Chemicals Codex, considerable research has been completed demonstrating the cariostatic— caries preventing—properties of fluoride. Fluoride is now added to many municipal water supplies to provide a level of 1 mg/L, and many dental products are formulated with it. Fluoride is in the formulation of many over-the-counter dietary supplements as well. 

The intake of fluoride as a constituent of substances described in FCC monographs, even at the maximum limits established for fluoride, is not expected to significantly add to the human daily fluoride intake from other sources and is well within the various limits described in the Institute of Medicine s committee report. Nonetheless, given that toxicological manifestations have been amply demonstrated for fluoride, as described in the report, the maintenance of fluoride limits in drinking water and food, and thus food additives, appears consistent with sound public health policy. Therefore, the Committee on Food Chemicals Codex considers that maintaining fluoride limits for relevant food additives and ingredients is justified. 

Because of the difficulties in analyzing for fluoride in food chemicals, the committee intends to adopt new analytical methods for fluoride as soon as adequate validation is submitted. Furthermore, in view of the considerable variation in fluoride limits for additives and ingredients in various national and international compendia, the committee deems harmonization of fluoride limits between the FCC and other compendia to be desirable. 

Perform a blank determination (see General Provisions), and make any necessary correction. Each milliliter of 0.1 N perchloric acid is equivalent to 20.12 mg of C4H4KNO4S. Fluoride Determine as directed in Method III under Fluoride Limit Test, Appendix IIIB, using a 4-g sample. 

Fluoride Determine as directed in Method V under Fluoride Limit Test, Appendix IIIB. 

Assay Dissolve about 1 g of sample, accurately weighed, in 50 mL of water, add 50.0 mL of 0.05 M disodium EDTA and 20 mL of pH 4.5 buffer solution (77.1 g of ammonium acetate and 57 mL of glacial acetic acid in 1000 mL of aqueous solution), and boil gently for 5 min. Cool, and add 50 mL of alcohol and 2 mL of dithizone TS. Back titrate with 0.05 M zinc sulfate to a bright rose-pink color. Perform a blank determination (see General Provisions), and make any necessary correction. The milliliters of 0.05 M disodium EDTA consumed is equivalent to 50 minus the milliliters of 0.05 M zinc sulfate used. Each milliliter of 0.05 M disodium EDTA is equivalent to 23.72 mg of A1K(S04)2T2H20. Ammonium Salts Add 1 g of sample to 10 mL of 1 N sodium hydroxide in a small beaker, and heat on a steam bath for 1 min. The odor of ammonia is not perceptible. Fluoride Determine as directed in Method V under Fluoride Limit Test, Appendix IIIB. 

Arsenic Determine as directed under Arsenic Limit Test, Appendix IIIB, using a solution of 1 g of sample in 35 mL of water. Fluoride Determine as directed in Method /Funder the Fluoride Limit Test, Appendix IIIB, using a 2-g sample, Buffer Solution B, and 0.1 mL of Fluoride Standard Solution. 

Fluoride Determine as directed under Fluoride Limit Test, Appendix NIB, using 1.0 g of sample, accurately weighed. Lead Determine as directed under Lead Limit Test, Appendix IIIB, using 10 mL of the following solution and 4 pig of lead (Pb) ion in the control Transfer 4.0 g of sample, accurately weighed, into a 250-mL beaker, cautiously add 50 mL of nitric acid, and evaporate just to dryness on a steam bath. Add 20 mL of nitric acid, repeat the evaporation, cool, and dissolve the residue in sufficient water containing 4 drops of nitric acid to make 40.0 mL. 

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