---
kind: "section"
citation: "21 C.F.R. § 173.40"
title: "21"
number: "173.40"
heading: "Molecular sieve resins."
url: "https://uscodex.org/cfr/21/173.40"
---

# §173.40. Molecular sieve resins.


Molecular sieve resins may be safely used in the processing of food under the following prescribed conditions:

- (a) The molecular sieve resins consist of purified dextran having an average molecular weight of 40,000, cross-linked with epichlorohydrin in a ratio of 1 part of dextran to 10 parts of epichlorohydrin, to give a stable three dimensional structure. The resins have a pore size of 2.0 to 3.0 milliliters per gram of dry resin (expressed in terms of water regain), and a particle size of 10 to 300 microns.
- (b) The molecular sieve resins are thoroughly washed with potable water prior to their first use in contact with food.
- (c) Molecular sieve resins are used as the gel filtration media in the final purification of partially delactosed whey. The gel bed shall be maintained in a sanitary manner in accordance with good manufacturing practice so as to prevent microbial build-up on the bed and adulteration of the product.

## Notes

### Authority

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

### Source

Source: 42 FR 14526, Mar. 15, 1977, unless otherwise noted.