# 21 CFR § 573.640 - Methyl esters of higher fatty acids.

§ 573.640 Methyl esters of higher fatty acids.

The food additive methyl esters of higher fatty acids may be safely used in animal feeds in accordance with the following prescribed conditions:

(a) The food additive is manufactured by reaction of methyl alcohol with feed-grade fats or oils and consists of not less than 70 percent methyl esters of the following straight-chain monocarboxylic acids: Docosahexanoic acid, eicosapentanoic acid, linoleic acid, myristic acid, oleic acid, palmitic acid, palmitoleic acid, and stearic acid, and lesser amounts of the associated acid esters.

(b) The food additive meets the following specifications:

(1) Free methyl alcohol not to exceed 150 parts per million.

(2) Unsaponifiable matter not to exceed 2 percent.

(3) It is free of chick-edema factor or other factors toxic to chicks, as evidenced during the bioassay method for determining the chick-edema factor as prescribed in paragraph (b)(4)(ii) of this section.

(4) For the purposes of this section:

(i) Unsaponifiable matter shall be determined by the method described in Section 28.081, “Unsaponifiable Residue (20) - Official Final Action” of the “Official Methods of Analysis of the Association of Official Analytical Chemists,” 13th Ed., 1980, p. 451, which is incorporated by reference. Copies are available from the AOAC INTERNATIONAL, 481 North Frederick Ave., suite 500, Gaithersburg, MD 20877, or available for inspection 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/code_of_federal_regulations/ibr_locations.html.

(ii) The chick-edema factor bioassay method described under “26. Oils, Fats, and Waxes” in the Journal of the Association of Official Agricultural Chemists, Vol. 44, Page 146 (1961), or the method described under “Chick-Edema Factor - Bioassay Method (34) - Official Final Action” in §§ 28.113-28.117, “Official Methods of Analysis of the Association of Official Analytical Chemists,” 12th Ed., 1975, pp. 509-511, which is incorporated by reference, shall be employed. (Copies of the methods are available from the AOAC INTERNATIONAL, 481 North Frederick Ave., suite 500, Gaithersburg, MD 20877, or available for inspectionat 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/code_of_federal_regulations/ibr_locations.html. ) The presence of chick-edema factor shall be determined by a comparison between the mean log of the pericardial fluid volumes of a test group and of a concurrent negative control group. The significance of the difference in pericardial fluid volumes between the test group and the negative control group is determined by calculating a “t” value according to the formula:

$t=\frac{{\stackrel{—}{x}}_{t}-{\stackrel{—}{x}}_{c}}{\sqrt{\left({s}_{t}^{2}/{n}_{t}\right)+\left({s}_{c}^{2}/{n}_{c}\right)}}$

where:
x
t and x
c are the means of the logs of the pericardial fluid volumes of the test and control groups, respectively;
nt and nc are the number of chicks in the respective groups;
st2 and sc2 are the variances of the test and control groups, respectively.
The variances are calculated as follows:

${s}^{2}=\frac{n\left(\sum {x}^{2}\right)-{\left(\sum x\right)}^{2}}{n\left(n-1\right)}$

where:
Σx is the sum of the logs of the pericardial fluid volumes;
Σx2 is the sum of the squares of the logs of the pericardial fluid volumes for either the test t or control c group data.
The test sample is judged to contain chick-edema factor if the calculated “t” exceeds +1.3 and the mean log of the pericardial fluid volume obtained from the negative control group multiplied by 100 is less than 1.1461.

(iii) “Other factors toxic to chicks” referred to in paragraph (b)(3) of this section shall be determined during the course of the bioassay test described in paragraph (b)(4)(ii) of this section, on the basis of chick deaths or other abnormalities not attributable to chick-edema factor or to the experimental conditions of the test.

(c) It is used or intended for use as a supplementary source of fat for animal feed.

(d) To assure safe use of the additive, in addition to the other information required by the act:

(1) The label and labeling of the additive, and any feed additive supplement, feed additive concentrate, feed additive premix, or complete feed prepared therefrom shall bear:

(i) The name of the additive.

(ii) The designation “feed grade” in juxtaposition with the name and equally as prominent.

(2) The label or labeling of the additive and any feed additive supplement, feed additive concentrate, feed additive premix, or complete feed prepared therefrom shall bear adequate directions for use.

[41 FR 38652, Sept. 10, 1976, as amended at 47 FR 9397, Mar. 5, 1982; 54 FR 18281, Apr. 28, 1989; 70 FR 40880, July 15, 2005; 70 FR 67651, Nov. 8, 2005]