---
kind: "section"
citation: "21 C.F.R. § 184.1769a"
title: "21"
number: "184.1769a"
heading: "Sodium metasilicate."
url: "https://uscodex.org/cfr/21/184.1769a"
---

# §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 (Na2SiO3·5H2O), and the nonahydrate (Na2SiO3·9H2O).
- (b) The ingredient must be of a purity suitable for its intended use.
- (c) In accordance with [§ 184.1(b)(1)](/cfr/21/184.1.md?p=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:
  - (1) The ingredient is used as a processing aid as defined in [§ 170.3(o)(24)](/cfr/21/170.3.md?p=o-24) of this chapter.
  - (2) The ingredient is used to treat the following foods at levels not to exceed current good manufacturing practice: for use in washing and lye peeling of fruits, vegetables, and nuts when used in accordance with [§ 173.315](/cfr/21/173.315.md) of this chapter; for use as a denuding agent in tripe; for use as a hog scald agent in removing hair; and for use as a corrosion preventative in canned and bottled water when used in accordance with [§ 165.110](/cfr/21/165.110.md) of this chapter.
- (d) Prior sanctions for this ingredient different from the uses established in this section do not exist or have been waived.

## Notes

### Amendments

[50 FR 38781, Sept. 25, 1985; 50 FR 42011, Oct. 17, 1985, as amended at 72 FR 10357, Mar. 8, 2007; 73 FR 8608, Feb. 14, 2008]

### Authority

Authority: 21 U.S.C. 321, 342, 348, 371.

### Source

Source: 42 FR 14653, Mar 15, 1977, unless otherwise noted.

### Amendments

[50 FR 38781, Sept. 25, 1985; 50 FR 42011, Oct. 17, 1985, as amended at 72 FR 10357, Mar. 8, 2007; 73 FR 8608, Feb. 14, 2008]