Code of Federal Regulations Title 21. Food and Drugs § 21.184.1769a Sodium metasilicate

(a) Sodium metasilicate (CAS Reg. No. 6834–92–0) is a strongly alkaline white powder. It does not occur naturally but rather is synthesized by melting sand with sodium carbonate at 1400 °C. The commercially available forms of sodium metasilicate are the anhydrous form (Na₂SiO₃), the pentahydrate (Na₂SiO₃5H₂O), and the nonahydrate (Na₂SiO₃9H₂O).

(b) The ingredient must be of a purity suitable for its intended use.

(c) In accordance with § 184.1(b)(1), the ingredient is used in food with no limitation other than current good manufacturing practice. The affirmation of this ingredient as generally recognized as safe (GRAS) as a direct human food ingredient is based upon the following current good manufacturing practice conditions of use:

(d) Prior sanctions for this ingredient different from the uses established in this section do not exist or have been waived.