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U.S. Department of Health and Human Services

CFR - Code of Federal Regulations Title 21

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The information on this page is current as of Dec 22, 2023.

For the most up-to-date version of CFR Title 21, go to the Electronic Code of Federal Regulations (eCFR).

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Help | More About 21CFR
[Code of Federal Regulations]
[Title 21, Volume 3]
[CITE: 21CFR172.320]



Subpart D - Special Dietary and Nutritional Additives

Sec. 172.320 Amino acids.

The food additive amino acids may be safely used as nutrients added to foods in accordance with the following conditions:

(a) The food additive consists of one or more of the following individual amino acids in the free, hydrated, or anhydrous form, or as the hydrochloride, sodium, or potassium salts:

(1) L-Alanine

(2) L-Arginine

(3) L-Asparagine

(4) L-Aspartic acid

(5) L-Cysteine

(6) L-Cystine

(7) L-Glutamic acid

(8) L-Glutamine

(9) Aminoacetic acid (glycine)

(10) L-Histidine

(11) L-Isoleucine

(12) L-Leucine

(13) L-Lysine

(14) DL-Methionine (not for infant foods)

(15) L-Methionine

(16) L-Phenylalanine

(17) L-Proline

(18) L-Serine

(19) L-Threonine

(20) L-Tryptophan

(21) L-Tyrosine

(22) L-Valine

(b) The food additive meets the following specifications:

(1) As found in Food Chemicals Codex:

(i) L-Alanine, pages 28 and 29.

(ii) L-Arginine, pages 69 and 70.

(iii) L-Arginine Monohydrochloride, pages 70 and 71.

(iv) L-Cysteine Monohydrochloride, pages 269 and 270.

(v) L-Cystine, pages 270 and 271.

(vi) Aminoacetic acid (glycine), pages 457 and 458.

(vii) L-Leucine, pages 577 and 578.

(viii) DL-Methionine, pages 641 and 642.

(ix) L-Methionine, pages 642 and 643.

(x) L-Tryptophan, pages 1060 and 1061.

(xi) L-Phenylalanine, pages 794 and 795.

(xii) L-Proline, pages 864 and 865.

(xiii) L-Serine, pages 915 and 916.

(xiv) L-Threonine, pages 1031 and 1032.

(xv) L-Glutamic Acid Hydrochloride, page 440.

(xvi) L-Isoleucine, pages 544 and 545.

(xvii) L-Lysine Monohydrochloride, pages 598 and 599.

(xviii) Monopotassium L -glutamate, pages 697 and 698.

(xix) L-Tyrosine, page 1061.

(xx) L-Valine, pages 1072.

(2) As found in "Specifications and Criteria for Biochemical Compounds," NAS/NRC Publication, for the following:

(i) L-Asparagine

(ii) L-Aspartic acid

(iii) L-Glutamine

(iv) L-Histidine

(c) The additive(s) is used or intended for use to significantly improve the biological quality of the total protein in a food containing naturally occurring primarily intact protein that is considered a significant dietary protein source, provided that:

(1) A reasonable daily adult intake of the finished food furnishes at least 6.5 grams of naturally occurring primarily intact protein (based upon 10 percent of the daily allowance for the "reference" adult male recommended by the National Academy of Sciences in "Recommended Dietary Allowances," NAS Publication No. 1694.

(2) The additive(s) results in a protein efficiency ratio (PER) of protein in the finished ready-to-eat food equivalent to casein as determined by the method specified in paragraph (d) of this section.

(3) Each amino acid (or combination of the minimum number necessary to achieve a statistically significant increase) added results in a statistically significant increase in the PER as determined by the method described in paragraph (d) of this section. The minimum amount of the amino acid(s) to achieve the desired effect must be used and the increase in PER over the primarily intact naturally occurring protein in the food must be substantiated as a statistically significant difference with at least a probability (P) value of less than 0.05.

(4) The amount of the additive added for nutritive purposes plus the amount naturally present in free and combined (as protein) form does not exceed the following levels of amino acids expressed as percent by weight of the total protein of the finished food:

Percent by weight of total
protein (expressed as free
amino acid)
L-Aspartic acid (including L-asparagine)7.0
L-Cystine (including L-cysteine)2.3
L-Glutamic acid (including L-glutamine)12.4
Aminoacetic acid (glycine)3.5
L- and DL-Methionine3.1

(d) Compliance with the limitations concerning PER under paragraph (c) of this section shall be determined by the method described in sections 43.212-43.216, "Official Methods of Analysis of the Association of Official Analytical Chemists." Each manufacturer or person employing the additive(s) under the provisions of this section shall keep and maintain throughout the period of his use of the additive(s) and for a minimum of 3 years thereafter, records of the tests required by this paragraph and other records required to assure effectiveness and compliance with this regulation and shall make such records available upon request at all reasonable hours by any officer or employee of the Food and Drug Administration, or any other officer or employee acting on behalf of the Secretary of Health and Human Services and shall permit such officer or employee to conduct such inventories of raw and finished materials on hand as he deems necessary and otherwise to check the correctness of such records.

(e) To assure safe use of the additive, the label and labeling of the additive and any premix thereof shall bear, in addition to the other information required by the Act, the following:

(1) The name of the amino acid(s) contained therein including the specific optical and chemical form.

(2) The amounts of each amino acid contained in any mixture.

(3) Adequate directions for use to provide a finished food meeting the limitations prescribed by paragraph (c) of this section.

(f) The food additive amino acids added as nutrients to special dietary foods that are intended for use solely under medical supervision to meet nutritional requirements in specific medical conditions and comply with the requirements of part 105 of this chapter are exempt from the limitations in paragraphs (c) and (d) of this section and may be used in such foods at levels not to exceed good manufacturing practices.

(g) The standards required in this section are incorporated by reference into this section with the approval of the Director of the Federal Register under 5 U.S.C. 552(a) and 1 CFR part 51. Copies may be examined at the Dockets Management Staff (HFA-305), Food and Drug Administration, 5630 Fishers Lane, Rm. 1061, Rockville, MD 20852, 240-402-7500, between 9 a.m. and 4 p.m., Monday through Friday, or at the National Archives and Records Administration (NARA). For information on the availability of this material at NARA, call 202-741-6030 or go to: http://www.archives.gov/federal-register/cfr/ibr-locations.html.

(1) AOAC INTERNATIONAL, 481 North Frederick Ave., suite 500, Gaithersburg, MD 20877:

(i) Sections 43.212-43.216, "Official Methods of Analysis of the Association of Official Analytical Chemists," 13th Ed. (1980).

(ii) [Reserved]

(2) National Academy of Sciences, available from the Dockets Management Staff (HFA-305), Food and Drug Administration, 5630 Fishers Lane, Rm. 1061, Rockville, MD 20852, 240-402-7500, between 9 a.m. and 4 p.m., Monday through Friday:

(i) "Recommended Dietary Allowances," NAS Publication No. 1694, 7th Ed. (1968).

(ii) "Specifications and Criteria for Biochemical Compounds," NAS/NRC Publication, 3rd Ed. (1972).

(3) United States Pharmacopeial Convention, 12601 Twinbrook Pkwy., Rockville, MD 20852 (Internet address http://www.usp.org ):

(i) Food Chemicals Codex, 7th ed. (2010), pages 28, 29, 69, 70, 71, 269, 270, 271, 440, 457, 458, 544, 545, 577, 578, 598, 599, 641, 642, 643, 697, 698, 794, 795, 864, 865, 915, 916, 1031, 1032, 1060, 1061, and 1072.

(ii) [Reserved]

[78 FR 71461, Nov. 29, 2013, as amended at 88 FR 17719, Mar. 24, 2023]