Food and Drug Administration, HHS § 173.25

under the following prescribed condi- adjuvant substances required in the tions: production of such basic polymer. (a) The ion-exchange membrane is These optional adjuvant substances prepared by subjecting a polyethylene may include substances used in accord- base conforming to § 177.1520 of this ance with § 174.5 of this chapter. chapter to polymerization with styrene (c) Conditions of use. (1) until the polystyrene phase of the base Perfluorinated ion exchange mem- is not less than 16 percent nor more branes described in paragraph (a) of than 30 percent by weight. The base is this section may be used in contact then modified by reaction with with all types of liquid foods at tem- chloromethyl methyl ether, and by peratures not exceeding 70° (158 °F). subsequent amination with trimethyl- (2) Maximum thickness of the copoly- amine, dimethylamine, diethylene- mer membrane is 0.007 inch (0.017 centi- triamine, or dimethylethanolamine. meter). (b) The ion-exchange membrane is (3) Perfluorinated ion exchange mem- manufactured so as to comply with the branes shall be maintained in a sani- following extraction limitations when tary manner in accordance with cur- subjected to the described procedure: rent good manufacturing practice so as Separate square-foot samples of mem- to prevent microbial adulteration of brane weighing approximately 14 grams food. each are cut into small pieces and (4) To assure their safe use, refluxed for 4 hours in 150 cubic centi- perfluorinated ionomer membranes meters of the following solvents: Dis- shall be thoroughly cleaned prior to tilled water, 5 percent acetic acid, and their first use in accordance with cur- 50 percent alcohol. Extraction from rent good manufacturing practice. each sample will not exceed 0.4 percent by weight of sample. [59 FR 15623, Apr. 4, 1994] (c) The ion-exchange membrane will § 173.25 Ion-exchange resins. be used in the production of grapefruit juice to adjust the ratio of citric acid Ion-exchange resins may be safely to total solids of the grapefruit juice used in the treatment of food under the produced. following prescribed conditions: (a) The ion-exchange resins are pre- § 173.21 Perfluorinated ion exchange pared in appropriate physical form, and membranes. consist of one or more of the following: Substances identified in paragraph (1) Sulfonated copolymer of styrene (a) of this section may be safely used as and divinylbenzene. ion exchange membranes intended for (2) Sulfonated anthracite coal meet- use in the treatment of bulk quantities ing the requirements of ASTM method of liquid food under the following pre- D388–38, Class I, Group 2, ‘‘Standard scribed conditions: Specifications for Classification of Coal (a) Identity. The membrane is a co- by Rank,’’ which is incorporated by polymer of ethanesulfonyl fluoride, 2- reference. Copies are available from [1-[difluoro-[(trifluoro- University Microfilms International, ethenyl)oxy]methyl]-1,2,2,2-tetrafluoro- 300 N. Zeeb Rd., Ann Arbor, MI 48106, or ethoxy]-1,1,2,2,-tetrafluoro-, with tetra- available for inspection at the National fluoroethylene that has been subse- Archives and Records Administration quently treated to hydrolyze the (NARA). For information on the avail- sulfonyl fluoride group to the sulfonic ability of this material at NARA, call acid. The Chemical Abstracts Service 202–741–6030, or go to: http:// name of this polymer is ethanesulfonic www.archives.gov/federallregister/ acid, 2-[1-[difluoro-[(trifluoro- codeloflfederallregulations/ ethenyl)oxy]methyl]-1,2,2,2-tetrafluoro- ibrllocations.html. ethoxy]-1,1,2,2,-tetrafluoro-, polymer (3) Sulfite-modified cross-linked phe- with tetrafluoroethane (CAS Reg. No. nol-formaldehyde, with modification 31175–20–9). resulting in sulfonic acid groups on (b) Optional adjuvant substances. The side chains. basic polymer identified in paragraph (4) Methacrylic acid-divinylbenzene (a) of this section may contain optional copolymer.

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(5) Cross-linked polystyrene, first (18) Methyl acrylate-divinylbenzene- chloromethylated then aminated with diethylene glycol divinyl ether trimethylamine, dimethylamine, di- terpolymer containing not less than 7 ethylenetriamine, or dimethylethanol- percent by weight of divinylbenzene amine. and not more than 2.3 percent by (6) Diethylenetriamine, triethylene- weight of diethylene glycol divinyl tetramine, or tetraethylenepentamine ether, aminolyzed with dimethyl- cross-linked with epichlorohydrin. aminopropylamine and quaternized (7) Cross-linked phenol-formaldehyde with methyl chloride. activated with one or both of the fol- (19) Epichlorohydrin cross-linked lowing: Triethylene tetramine and with ammonia and then quaternized tetraethylenepentamine. with methyl chloride to contain not (8) Reaction resin of formaldehyde, more than 18 percent strong base ca- acetone, and tetraethylenepentamine. pacity by weight of total exchange ca- (9) Completely hydrolyzed copoly- pacity [Chemical Abstracts Service mers of methyl acrylate and name: Oxirane (chloromethyl)-, poly- divinylbenzene. mer with ammonia, reaction product with chloromethane; CAS Reg. No. (10) Completely hydrolyzed 68036–99–7]. terpolymers of methyl acrylate, (20) Regenerated cellulose, cross- divinylbenzene, and acrylonitrile. linked and alkylated with epichloro- (11) Sulfonated terpolymers of sty- hydrin and propylene oxide, then sulfo- rene, divinylbenzene, and acrylonitrile nated whereby the amount of epi- or methyl acrylate. chlorohydrin plus propylene oxide em- (12) Methyl acrylate-divinylbenzene ployed does not exceed 250 percent by copolymer containing not less than 2 weight of the starting quantity of cel- percent by weight of divinylbenzene, lulose. aminolyzed with dimethylaminopro- (b) Ion-exchange resins are used in pylamine. the purification of foods, including po- (13) Methyl acrylate-divinylbenzene table water, to remove undesirable ions copolymer containing not less than 3.5 or to replace less desirable ions with percent by weight of divinylbenzene, one or more of the following: bicarbon- aminolyzed with dimethylaminopro- ate, calcium, carbonate, chloride, hy- pylamine. drogen, hydroxyl, magnesium, potas- (14) Epichlorohydrin cross-linked sium, sodium, and sulfate except that: with ammonia. The ion-exchange resin identified in (15) Sulfonated tetrapolymer of sty- paragraph (a)(12) of this section is used rene, divinylbenzene, acrylonitrile, and only in accordance with paragraph methyl acrylate derived from a mix- (b)(1) of this section, the ion-exchange ture of monomers containing not more resin identified in paragraph (a)(13) of than a total of 2 percent by weight of this section is used only in accordance acrylonitrile and methyl acrylate. with paragraph (b)(2) of this section, (16) Methyl acrylate-divinylbenzene- the resin identified in paragraph (a)(16) diethylene glycol divinyl ether of this section is used only in accord- terpolymer containing not less than 3.5 ance with paragraph (b)(1) or (b)(2) of percent by weight of divinylbenzene this section, the ion-exchange resin and not more than 0.6 percent by identified in paragraph (a)(17) of this weight of diethylene glycol divinyl section is used only in accordance with ether, aminolyzed with dimethyl- paragraph (b)(3) of this section, the aminopropylamine. ion-exchange resin identified in para- (17) Styrene-divinylbenzene cross- graph (a)(18) of this section is used only linked copolymer, first in accordance with paragraph (b)(4) of chloromethylated then aminated with this section, and the ion-exchange dimethylamine and oxidized with hy- resin identified in paragraph (a)(20) of drogen peroxide whereby the resin con- this section is used only in accordance tains not more than 15 percent by with paragraphs (b)(5) and (d) of this weight of vinyl N,N-dimethylbenzyl- section. amine-N-oxide and not more than 6.5 (1) The ion-exchange resins identified percent by weight of nitrogen. in paragraphs (a) (12) and (16) of this

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section are used to treat water for use food passing through the resin bed is in the manufacture of distilled alco- maintained at 50 °C or less and the flow holic beverages, subject to the fol- rate of the water or food passing lowing conditions: through the bed is not less than 0.5 gal- (i) The water is subjected to treat- lon per cubic foot per minute. ment through a mixed bed consisting of (ii) The ion-exchange resin identified one of the resins identified in para- in paragraph (a)(16) of this section is graph (a) (12) or (16) of this section and used to treat water and aqueous food one of the strongly acidic cation-ex- only of the types identified under cat- change resins in the hydrogen form egories I, II, and VI-B in Table 1 of identified in paragraphs (a) (1), (2), and § 176.170(c) of this chapter, Provided, (11) of this section; or that either: (ii) The water is first subjected to (A) The temperature of the water or one of the resins identified in para- food passing through the resin bed is graph (a) (12) or (16) of this section and maintained at 50 °C or less and the flow is subsequently subjected to treatment rate of the water or food passing through a bed of activated carbon or through the bed is not less than 0.5 gal- one of the strongly acidic cation-ex- lon per cubic foot per minute; or change resins in the hydrogen form (B) Extracts of the resin will be found identified in paragraphs (a) (1), (2), and to contain no more than 1 milligram/ (11) of this section. kilogram dimethylaminopropylamine (iii) The temperature of the water in each of the food simulants, distilled passing through the resin beds identi- water and 10 percent ethanol, when, fied in paragraphs (b)(1) (i) and (ii) of following washing and pretreatment of this section is maintained at 30 °C or the resin in accordance with less, and the flow rate of the water § 173.25(c)(1), the resin is subjected to passing through the beds is not less the following test under conditions than 2 gallons per cubic foot per simulating the actual temperature and minute. flow rate of use: ‘‘The Determination of (iv) The ion-exchange resins identi- 3-Dimethylaminopropylamine in Food fied in paragraph (a) (12) or (16) of this Simulating Extracts of Ion Exchange section are exempted from the require- Resins,’’ February 4, 1998, which is in- ments of paragraph (c)(4) of this sec- corporated by reference in accordance tion, but the strongly acidic cation-ex- with 5 U.S.C. 552(a) and 1 CFR part 51. change resins referred to in paragraphs Copies are available from the Office of (b)(1) (i) and (ii) of this section used in Food Additive Safety (HFS–200), Center the process meet the requirements of for Food Safety and Applied Nutrition, paragraph (c)(4) of this section, except Food and Drug Administration, 5100 for the exemption described in para- Paint Branch Pkwy., College Park, MD graph (d) of this section. 20740, 240–402–1200, or may be examined (2) The ion-exchange resins identified at the Center for Food Safety and Ap- in paragraphs (a) (13) and (16) of this plied Nutrition’s Library, 5100 Paint section are used to treat water and Branch Pkwy., College Park, MD 20740, aqueous food only of the types identi- or at the National Archives and fied under Categories I, II, and VI-B in Records Administration (NARA). For table 1 of § 176.170(c) of this chapter: information on the availability of this Provided, That the temperature of the material at NARA, call 202–741–6030, or water or food passing through the resin go to: http://www.archives.gov/ beds is maintained at 50 °C or less and federallregister/ the flow rate of the water or food pass- codeloflfederallregulations/ ing through the beds is not less than 0.5 ibrllocations.html. gallon per cubic foot per minute. (3) The ion-exchange resin identified (i) The ion-exchange resin identified in paragraph (a)(17) of this section is in paragraph (a)(13) of this section is used only for industrial application to used to treat water and aqueous food treat bulk quantities of aqueous food, only of the types identified under cat- including potable water, or for treat- egories I, II, and VI-B in Table 1 of ment of municipal water supplies, sub- § 176.170(c) of this chapter: Provided, ject to the condition that the tempera- That the temperature of the water or ture of the food or water passing

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through the resin bed is maintained at treated in accordance with the manu- 25 °C or less and the flow rate of the facturer’s directions for preparing food or water passing through the bed them for use with food, the ion-ex- is not less than 2 gallons per cubic foot change resin is subjected to the fol- per minute. lowing test: Using a separate ion-ex- (4) The ion-exchange resin identified change column for each solvent, pre- in paragraph (a)(18) of this section is pare columns using 50 milliliters of the used to treat aqueous sugar solutions ready to use ion-exchange resin that is subject to the condition that the tem- to be tested. While maintaining the perature of the sugar solution passing highest temperature that will be en- through the resin bed is maintained at countered in use pass through these 82 °C (179.6 °F) or less and the flow rate beds at the rate of 350–450 milliliters of the sugar solution passing through per hour the three test solvents dis- the bed is not less than 46.8 liters per tilled water, 15 percent (by volume) cubic meter (0.35 gallon per cubic foot) ethyl alcohol, and 5 percent (by weight) of resin bed volume per minute. acetic acid. The first liter of effluent (5) The ion-exchange resin identified from each solvent is discarded, then in paragraph (a)(20) of this section is the next 2 liters are used to determine limited to use in aqueous process organic extractives. The 2-liter sample streams for the isolation and purifi- is carefully evaporated to constant cation of protein concentrates and iso- weight at 105 °C; this is total extrac- lates under the following conditions: tives. This residue is fired in a muffle (i) For resins that comply with the furnace at 850 °C to constant weight; requirements in paragraph (d)(2)(i) of this is ash. Total extractives, minus this section, the pH range for the resin ash equals the organic extractives. If shall be no less than 3.5 and no more the organic extractives are greater than 9, and the temperatures of water than 1 part per million of the solvent and food passing through the resin bed used, a blank should be run on the sol- shall not exceed 25 °C. vent and a correction should be made (ii) For resins that comply with the by subtracting the total extractives ob- requirements in paragraph (d)(2)(ii) of tained with the blank from the total this section, the pH range for the resin extractives obtained in the resin test. shall be no less than 2 and no more The solvents used are to be made as than 10, and the temperatures of water follows: and food passing through the resin Distilled water (de-ionized water is distilled). shall not exceed 50 °C. 15 percent ethyl alcohol made by mixing 15 (c) To insure safe use of ion-exchange volumes of absolute ethyl alcohol A.C.S. resins, each ion-exchange resin will be: reagent grade, with 85 volumes of distilled (1) Subjected to pre-use treatment by de-ionized water. the manufacturer and/or the user in ac- 5 percent acetic acid made by mixing 5 parts cordance with the manufacturer’s di- by weight of A.C.S. reagent grade glacial acetic acid with 95 parts by weight of dis- rections prescribed on the label or la- tilled de-ionized water. beling accompanying the resins, to guarantee a food-grade purity of ion- In addition to the organic extractives exchange resins, in accordance with limitation prescribed in this para- good manufacturing practice. graph, the ion-exchange resin identi- (2) Accompanied by label or labeling fied in paragraph (a)(17) of this section, to include directions for use consistent when extracted with each of the named with the intended functional purpose of solvents, distilled water, 50 percent al- the resin. cohol, and 5 percent acetic acid, will be (3) Used in compliance with the label found to result in not more than 7 or labeling required by paragraph (c)(2) parts per million of nitrogen extrac- of this section. tives (calculated as nitrogen) when the (4) Found to result in no more than 1 resin in the free-base form is subjected part per million of organic extractives to the following test immediately be- obtained with each of the named sol- fore each use: Using a separate 1–inch vents, distilled water, 15 percent alco- diameter glass ion-exchange column hol, and 5 percent acetic acid when, for each solvent, prepare each column having been washed and otherwise using 100 milliliters of ready to use ion-

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exchange resin that is to be tested. molecular weight of 40,000, cross-linked With the bottom outlet closed, fill each with epichlorohydrin in a ratio of 1 ion-exchange column with one of the part of dextran to 10 parts of three solvents at a temperature of 25 °C epichlorohydrin, to give a stable three until the solvent level is even with the dimensional structure. The resins have top of the resin bed. Seal each column a pore size of 2.0 to 3.0 milliliters per at the top and bottom and store in a gram of dry resin (expressed in terms vertical position at a temperature of 25 of water regain), and a particle size of °C. After 96 hours, open the top of each 10 to 300 microns. column, drain the solvent into a collec- (b) The molecular sieve resins are tion vessel, and analyze each drained thoroughly washed with potable water solvent and a solvent blank for nitro- prior to their first use in contact with gen by a standard micro-Kjeldahl food. method. (c) Molecular sieve resins are used as (d)(1) The ion-exchange resins identi- the gel filtration media in the final pu- fied in paragraphs (a)(1), (a)(2), (a)(11), rification of partially delactosed whey. and (a)(15) of this section are exempted The gel bed shall be maintained in a from the acetic acid extraction re- sanitary manner in accordance with quirement of paragraph (c)(4) of this good manufacturing practice so as to section. prevent microbial build-up on the bed (2) The ion-exchange resin identified and adulteration of the product. in paragraph (a)(20) of this section shall comply either with: § 173.45 Polymaleic acid and its so- (i) The extraction requirement in dium salt. paragraph (c)(4) of this section by using Polymaleic acid (CAS Reg. No. 26099– dilute sulfuric acid, pH 3.5 as a sub- 09–2) and its sodium salt (CAS Reg. No. stitute for acetic acid; or 70247–90–4) may be safely used in food (ii) The extraction requirement in in accordance with the following pre- paragraph (c)(4) of this section by using scribed conditions: reagent grade hydrochloric acid, di- (a) The additives have a weight-aver- luted to pH 2, as a substitute for acetic age molecular weight in the range of acid. The resin shall be found to result 540 to 850 and a number-average molec- in no more than 25 parts per million of ular weight in the range of 520 to 650, organic extractives obtained with each calculated as the acid. Molecular of the following solvents: Distilled weights shall be determined by a meth- water; 15 percent alcohol; and hydro- od entitled ‘‘Determination of Molec- chloric acid, pH 2. Blanks should be run ular Weight Distribution of for each of the solvents, and correc- Poly(Maleic) Acid,’’ March 17, 1992, pro- tions should be made by subtracting duced by Ciba-Geigy, Inc., Seven Sky- the total extractives obtained with the line Dr., Hawthorne, NY 10532–2188, blank from the total extractives ob- which is incorporated by reference in tained in the resin test. accordance with 5 U.S.C. 552(a) and 1 (e) Acrylonitrile copolymers identi- CFR part 51. Copies are available from fied in this section shall comply with the Office of Food Additive Safety the provisions of § 180.22 of this chap- (HFS–200), Center for Food Safety and ter. Applied Nutrition, Food and Drug Ad- ministration, 5100 Paint Branch Pkwy., [42 FR 14526, Mar. 15, 1977, as amended at 46 FR 40181, Aug. 7, 1981; 46 FR 57033, Nov. 20, College Park, MD 20740, 240–402–1200, or 1981; 49 FR 28830, July 17, 1984; 56 FR 16268, are available for inspection at the Cen- Apr. 22, 1991; 62 FR 7679, Feb. 20, 1997; 64 FR ter for Food Safety and Applied Nutri- 14609, Mar. 26, 1999; 64 FR 56173, Oct. 18, 1999; tion’s Library, 5100 Paint Branch 78 FR 14665, Mar. 7, 2013] Pkwy., College Park, MD 20740, or at the National Archives and Records Ad- § 173.40 Molecular sieve resins. ministration (NARA). For information Molecular sieve resins may be safely on the availability of this material at used in the processing of food under the NARA, call 202–741–6030, or go to: http:// following prescribed conditions: www.archives.gov/federallregister/ (a) The molecular sieve resins consist codeloflfederallregulations/ of purified dextran having an average ibrllocations.html.

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