§ 173.25 21 CFR Ch. I (4–1–09 Edition)

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. adjuvant substances required in the (5) Cross-linked polystyrene, first production of such basic polymer. chloromethylated then aminated with These optional adjuvant substances , , di- may include substances used in accord- ethylenetriamine, or dimethylethanol- ance with § 174.5 of this chapter. amine. (c) Conditions of use. (1) (6) , triethylene- Perfluorinated ion exchange mem- tetramine, or tetraethylenepentamine branes described in paragraph (a) of cross-linked with epichlorohydrin. this section may be used in contact (7) Cross-linked phenol-formaldehyde with all types of liquid foods at tem- activated with one or both of the fol- peratures not exceeding 70° (158 °F). lowing: Triethylene tetramine and (2) Maximum thickness of the copoly- tetraethylenepentamine. mer membrane is 0.007 inch (0.017 centi- (8) Reaction resin of formaldehyde, meter). acetone, and tetraethylenepentamine. (3) Perfluorinated ion exchange mem- (9) Completely hydrolyzed copoly- branes shall be maintained in a sani- mers of methyl acrylate and tary manner in accordance with cur- divinylbenzene. rent good manufacturing practice so as (10) Completely hydrolyzed to prevent microbial adulteration of terpolymers of methyl acrylate, food. divinylbenzene, and . (4) To assure their safe use, (11) Sulfonated terpolymers of sty- perfluorinated ionomer membranes rene, divinylbenzene, and acrylonitrile shall be thoroughly cleaned prior to or methyl acrylate. their first use in accordance with cur- (12) Methyl acrylate-divinylbenzene rent good manufacturing practice. copolymer containing not less than 2 percent by weight of divinylbenzene, [59 FR 15623, Apr. 4, 1994] aminolyzed with dimethylaminopro- pylamine. § 173.25 Ion-exchange resins. (13) Methyl acrylate-divinylbenzene Ion-exchange resins may be safely copolymer containing not less than 3.5 used in the treatment of food under the percent by weight of divinylbenzene, following prescribed conditions: aminolyzed with dimethylaminopro- (a) The ion-exchange resins are pre- pylamine. pared in appropriate physical form, and (14) Epichlorohydrin cross-linked consist of one or more of the following: with ammonia. (1) Sulfonated copolymer of styrene (15) Sulfonated tetrapolymer of sty- and divinylbenzene. rene, divinylbenzene, acrylonitrile, and

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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 (18) Methyl acrylate-divinylbenzene- section are used to treat water for use diethylene glycol divinyl ether in the manufacture of distilled alco- terpolymer containing not less than 7 holic beverages, subject to the fol- percent by weight of divinylbenzene lowing conditions: and not more than 2.3 percent by (i) The water is subjected to treat- weight of diethylene glycol divinyl ment through a mixed bed consisting of ether, aminolyzed with dimethyl- one of the resins identified in para- aminopropylamine and quaternized graph (a) (12) or (16) of this section and with methyl chloride. one of the strongly acidic cation-ex- (19) Epichlorohydrin cross-linked change resins in the hydrogen form with ammonia and then quaternized identified in paragraphs (a) (1), (2), and with methyl chloride to contain not (11) of this section; or more than 18 percent strong base ca- (ii) The water is first subjected to pacity by weight of total exchange ca- one of the resins identified in para- pacity [Chemical Abstracts Service graph (a) (12) or (16) of this section and name: Oxirane (chloromethyl)-, poly- is subsequently subjected to treatment mer with ammonia, reaction product through a bed of activated carbon or with chloromethane; CAS Reg. No. one of the strongly acidic cation-ex- 68036–99–7]. change resins in the hydrogen form (20) Regenerated cellulose, cross- identified in paragraphs (a) (1), (2), and linked and alkylated with epichloro- (11) of this section. hydrin and propylene oxide, then sulfo- (iii) The temperature of the water nated whereby the amount of epi- passing through the resin beds identi- chlorohydrin plus propylene oxide em- fied in paragraphs (b)(1) (i) and (ii) of ployed does not exceed 250 percent by this section is maintained at 30 °C or weight of the starting quantity of cel- less, and the flow rate of the water lulose. passing through the beds is not less (b) Ion-exchange resins are used in than 2 gallons per cubic foot per the purification of foods, including po- minute. table water, to remove undesirable ions (iv) The ion-exchange resins identi- or to replace less desirable ions with fied in paragraph (a) (12) or (16) of this one or more of the following: bicarbon- section are exempted from the require- ate, calcium, carbonate, chloride, hy- ments of paragraph (c)(4) of this sec- drogen, hydroxyl, magnesium, potas- tion, but the strongly acidic cation-ex- sium, sodium, and sulfate except that: change resins referred to in paragraphs The ion-exchange resin identified in (b)(1) (i) and (ii) of this section used in paragraph (a)(12) of this section is used the process meet the requirements of only in accordance with paragraph paragraph (c)(4) of this section, except

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for the exemption described in para- Paint Branch Pkwy., College Park, MD graph (d) of this section. 20740, or may be examined at the Cen- (2) The ion-exchange resins identified ter for Food Safety and Applied Nutri- in paragraphs (a) (13) and (16) of this tion’s Library, 5100 Paint Branch section are used to treat water and Pkwy., College Park, MD 20740, or at aqueous food only of the types identi- the National Archives and Records Ad- fied under Categories I, II, and VI-B in ministration (NARA). For information table 1 of § 176.170(c) of this chapter: on the availability of this material at Provided, That the temperature of the NARA, call 202–741–6030, or go to: http:// water or food passing through the resin www.archives.gov/federallregister/ beds is maintained at 50 °C or less and codeloflfederallregulations/ the flow rate of the water or food pass- ibrllocations.html. ing through the beds is not less than 0.5 (3) The ion-exchange resin identified gallon per cubic foot per minute. in paragraph (a)(17) of this section is (i) The ion-exchange resin identified used only for industrial application to in paragraph (a)(13) of this section is treat bulk quantities of aqueous food, used to treat water and aqueous food including potable water, or for treat- only of the types identified under cat- ment of municipal water supplies, sub- egories I, II, and VI-B in Table 1 of ject to the condition that the tempera- § 176.170(c) of this chapter: Provided, ture of the food or water passing That the temperature of the water or through the resin bed is maintained at food passing through the resin bed is 25 °C or less and the flow rate of the ° maintained at 50 C or less and the flow food or water passing through the bed rate of the water or food passing is not less than 2 gallons per cubic foot through the bed is not less than 0.5 gal- per minute. lon per cubic foot per minute. (4) The ion-exchange resin identified (ii) The ion-exchange resin identified in paragraph (a)(18) of this section is in paragraph (a)(16) of this section is used to treat aqueous sugar solutions used to treat water and aqueous food subject to the condition that the tem- only of the types identified under cat- perature of the sugar solution passing egories I, II, and VI-B in Table 1 of through the resin bed is maintained at § 176.170(c) of this chapter, Provided, 82 °C (179.6 °F) or less and the flow rate that either: of the sugar solution passing through (A) The temperature of the water or the bed is not less than 46.8 liters per food passing through the resin bed is cubic meter (0.35 gallon per cubic foot) maintained at 50 °C or less and the flow of resin bed volume per minute. rate of the water or food passing through the bed is not less than 0.5 gal- (5) The ion-exchange resin identified lon per cubic foot per minute; or in paragraph (a)(20) of this section is (B) Extracts of the resin will be found limited to use in aqueous process to contain no more than 1 milligram/ streams for the isolation and purifi- kilogram dimethylaminopropylamine cation of protein concentrates and iso- in each of the food simulants, distilled lates under the following conditions: water and 10 percent ethanol, when, (i) For resins that comply with the following washing and pretreatment of requirements in paragraph (d)(2)(i) of the resin in accordance with this section, the pH range for the resin § 173.25(c)(1), the resin is subjected to shall be no less than 3.5 and no more the following test under conditions than 9, and the temperatures of water simulating the actual temperature and and food passing through the resin bed flow rate of use: ‘‘The Determination of shall not exceed 25 °C. 3-Dimethylaminopropylamine in Food (ii) For resins that comply with the Simulating Extracts of Ion Exchange requirements in paragraph (d)(2)(ii) of Resins,’’ February 4, 1998, which is in- this section, the pH range for the resin corporated by reference in accordance shall be no less than 2 and no more with 5 U.S.C. 552(a) and 1 CFR part 51. than 10, and the temperatures of water Copies are available from the Division and food passing through the resin of Petition Control (HFS–215), Center shall not exceed 50 °C. for Food Safety and Applied Nutrition, (c) To insure safe use of ion-exchange Food and Drug Administration, 5100 resins, each ion-exchange resin will be:

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(1) Subjected to pre-use treatment by reagent grade, with 85 volumes of distilled the manufacturer and/or the user in ac- de-ionized water. cordance with the manufacturer’s di- 5 percent acetic acid made by mixing 5 parts rections prescribed on the label or la- by weight of A.C.S. reagent grade glacial acetic acid with 95 parts by weight of dis- beling accompanying the resins, to tilled de-ionized water. guarantee a food-grade purity of ion- exchange resins, in accordance with In addition to the organic extractives good manufacturing practice. limitation prescribed in this para- (2) Accompanied by label or labeling graph, the ion-exchange resin identi- to include directions for use consistent fied in paragraph (a)(17) of this section, with the intended functional purpose of when extracted with each of the named the resin. solvents, distilled water, 50 percent al- (3) Used in compliance with the label cohol, and 5 percent acetic acid, will be or labeling required by paragraph (c)(2) found to result in not more than 7 of this section. parts per million of nitrogen extrac- (4) Found to result in no more than 1 tives (calculated as nitrogen) when the part per million of organic extractives resin in the free-base form is subjected obtained with each of the named sol- to the following test immediately be- vents, distilled water, 15 percent alco- fore each use: Using a separate 1–inch 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- treated in accordance with the manu- exchange resin that is to be tested. facturer’s directions for preparing With the bottom outlet closed, fill each them for use with food, the ion-ex- ion-exchange column with one of the change resin is subjected to the fol- three solvents at a temperature of 25 °C lowing test: Using a separate ion-ex- until the solvent level is even with the change column for each solvent, pre- top of the resin bed. Seal each column pare columns using 50 milliliters of the at the top and bottom and store in a ready to use ion-exchange resin that is vertical position at a temperature of 25 to be tested. While maintaining the °C. After 96 hours, open the top of each highest temperature that will be en- column, drain the solvent into a collec- countered in use pass through these tion vessel, and analyze each drained beds at the rate of 350–450 milliliters solvent and a solvent blank for nitro- per hour the three test solvents dis- gen by a standard micro-Kjeldahl tilled water, 15 percent (by volume) method. ethyl alcohol, and 5 percent (by weight) (d)(1) The ion-exchange resins identi- acetic acid. The first liter of effluent fied in paragraphs (a)(1), (a)(2), (a)(11), from each solvent is discarded, then and (a)(15) of this section are exempted the next 2 liters are used to determine from the acetic acid extraction re- organic extractives. The 2-liter sample quirement of paragraph (c)(4) of this is carefully evaporated to constant section. ° weight at 105 C; this is total extrac- (2) The ion-exchange resin identified tives. This residue is fired in a muffle in paragraph (a)(20) of this section ° furnace at 850 C to constant weight; shall comply either with: this is ash. Total extractives, minus (i) The extraction requirement in ash equals the organic extractives. If paragraph (c)(4) of this section by using the organic extractives are greater dilute sulfuric acid, pH 3.5 as a sub- than 1 part per million of the solvent stitute for acetic acid; or used, a blank should be run on the sol- (ii) The extraction requirement in vent and a correction should be made paragraph (c)(4) of this section by using by subtracting the total extractives ob- reagent grade hydrochloric acid, di- tained with the blank from the total luted to pH 2, as a substitute for acetic extractives obtained in the resin test. acid. The resin shall be found to result The solvents used are to be made as in no more than 25 parts per million of follows: organic extractives obtained with each Distilled water (de-ionized water is distilled). of the following solvents: Distilled 15 percent ethyl alcohol made by mixing 15 water; 15 percent alcohol; and hydro- volumes of absolute ethyl alcohol A.C.S. chloric acid, pH 2. Blanks should be run

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for each of the solvents, and correc- duced by Ciba-Geigy, Inc., Seven Sky- tions should be made by subtracting line Dr., Hawthorne, NY 10532–2188, the total extractives obtained with the which is incorporated by reference in blank from the total extractives ob- accordance with 5 U.S.C. 552(a) and 1 tained in the resin test. CFR part 51. Copies are available from (e) Acrylonitrile copolymers identi- the Division of Product Policy, Center fied in this section shall comply with for Food Safety and Applied Nutrition the provisions of § 180.22 of this chap- (HFS–205), Food and Drug Administra- ter. tion, 5100 Paint Branch Pkwy., College [42 FR 14526, Mar. 15, 1977, as amended at 46 Park, MD 20740, or are available for in- FR 40181, Aug. 7, 1981; 46 FR 57033, Nov. 20, spection at the Center for Food Safety 1981; 49 FR 28830, July 17, 1984; 56 FR 16268, and Applied Nutrition’s Library, 5100 Apr. 22, 1991; 62 FR 7679, Feb. 20, 1997; 64 FR Paint Branch Pkwy., College Park, MD 14609, Mar. 26, 1999; 64 FR 56173, Oct. 18, 1999] 20740, or at the National Archives and § 173.40 Molecular sieve resins. Records Administration (NARA). For Molecular sieve resins may be safely information on the availability of this used in the processing of food under the material at NARA, call 202–741–6030, or following prescribed conditions: go to: http://www.archives.gov/ (a) The molecular sieve resins consist federallregister/ of purified dextran having an average codeloflfederallregulations/ molecular weight of 40,000, cross-linked ibrllocations.html. with epichlorohydrin in a ratio of 1 (b) The additives may be used, indi- part of dextran to 10 parts of vidually or together, in the processing epichlorohydrin, to give a stable three of beet sugar juice and liquor or of cane dimensional structure. The resins have sugar juice and liquor to control min- a pore size of 2.0 to 3.0 milliliters per eral scale. gram of dry resin (expressed in terms (c) The additives are to be used so of water regain), and a particle size of that the amount of either or both addi- 10 to 300 microns. tives does not exceed 4 parts per mil- (b) The molecular sieve resins are lion (calculated as the acid) by weight thoroughly washed with potable water of the beet or cane sugar juice or liquor prior to their first use in contact with process stream. food. (c) Molecular sieve resins are used as [51 FR 5315, Feb. 13, 1986, as amended at 61 the gel filtration media in the final pu- FR 386, Jan. 5, 1996] rification of partially delactosed whey. The gel bed shall be maintained in a § 173.50 Polyvinylpolypyrrolidone. sanitary manner in accordance with The food additive polyvinylpoly- good manufacturing practice so as to pyrrolidone may be safely used in ac- prevent microbial build-up on the bed cordance with the following prescribed and adulteration of the product. conditions: (a) The additive is a homopolymer of § 173.45 Polymaleic acid and its so- dium salt. purified vinylpyrrolidone catalytically produced under conditions producing Polymaleic acid (CAS Reg. No. 26099– polymerization and cross-linking such 09–2) and its sodium salt (CAS Reg. No. that an insoluble polymer is produced. 70247–90–4) may be safely used in food in accordance with the following pre- (b) The food additive is so processed scribed conditions: that when the finished polymer is (a) The additives have a weight-aver- refluxed for 3 hours with water, 5 per- age molecular weight in the range of cent acetic acid, and 50 percent alco- 540 to 850 and a number-average molec- hol, no more than 50 parts per million ular weight in the range of 520 to 650, of extractables is obtained with each calculated as the acid. Molecular solvent. weights shall be determined by a meth- (c) It is used or intended for use as a od entitled ‘‘Determination of Molec- clarifying agent in beverages and vin- ular Weight Distribution of egar, followed by removal with filtra- Poly(Maleic) Acid,’’ March 17, 1992, pro- tion.

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