§ 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.
更多关于美国 FDA 可直接加入食品中的辅助性食品添加剂的种类法规，请点击美国FDA 21 CFR 第173部分可直接加入食品中的辅助性食品添加剂种类汇总
