August, 19631 ANALYTICAL METHODS COMMITTEE 583 Analytical Methods Commit tee REPORT PREPARED BY THE MEAT PRODUCTS SUB-COMMITTEE Nitrogen Factors for Chicken THE Analytical Methods Committee has received the following report from its Meat Products Sub-committee. The report has been approved by the Analytical Methods Committee and its publication has been authorised by the Council. REPORT The Meat Products Sub-committee of the Analytical Methods Committee responsible for the preparation of this Report was constituted as follows : Dr. S. M. Herschdoerfer (Chair- man), Mr. s. Back, Mr. P. 0. Dennis, Mr. J. R. Fraser, Mr. H. C. Hornsey, Dr. A. J. Kidney, Mr. T. McLachlan, Dr. R. A. Lawrie, Dr. A. McM. Taylor and Mr. E. F. Williams, with Dr. C . H. Tinker as Secretary. As in its reports on pork1 and beef,2 the Sub-committee agreed to base on Stubbs and More’s method its recommendations for the determination of the raw fresh meat content in products made from chicken meat.A nitrogen factor of 3.5 is generally used for such determinations, and the Sub-committee decided to test the validity of this factor and, if necessary, to recommend the use of alternative factors. Again, the Sub-committee was fortunate in obtaining the collaboration of several laboratories of meat-product manufacturers (see below), who agreed to analyse chicken carcases according to the requirements of the Sub-committee. The Sub-committee recommended that older heavier birds should be examined, as it is unusual for young light birds to be used for manufacturing purposes. It was also arranged that the breast meat should be analysed separately from the other meat, as breast meat and dark meat are sometimes used separately for manufacturing purposes.The instructions listed below were issued to the collaborating laboratories. PKOCEDURE FOR THE PREPARATION OF SAMPLES 1. The neck, head and feet should be removed from the already eviscerated and plucked chicken. 2. The breast meat should be dissected completely, weighed, and then finely minced and mixed. 3. All other flesh and skin (exclusive only of any adhering intestinal fat), should then be completely dissected from the bones, weighed, finely minced and then mixed. 4. Portions from 2 and 3 should then be weighed out for moisture, fat, ash and nitrogen determinations. 5. All these operations should be performed with a minimum of delay, to minimise evaporation losses. 6.When possible, the following details should be supplied- (a) Weight and age of bird. (b) Weights of “breast meat” and “other meat.” (c) Percentages of moisture, fat, ash, nitrogen and nitrogen expressed on the fat-free, on both the “breast meat” and the “other meat.” RESULTS Those marked with an asterisk were obtained on samples taken by the procedure outlined above, and the values thus marked in the “Whole Carcase” section of the chart have been calculated from the values for the component parts. In addition, the values marked with a dagger in this section were obtained on composite samples prepared by dissecting and comminuting all flesh and skin from the entire carcase.In other tests sampling was not carried out by the prescribed The results collected by the Sub-committee are shown in Fig. 1.584 ANALYTICAL METHODS COMMITTEE [AnaZyst, Vol. 88 method, since the analyses were completed before the instructions had been issued. The resulting figures may be to some extent affected by this variation; it would, for instance, be reasonable to assume that the average figure for leg meat found by Laboratory C would have been higher had the skin not been removed. The Sub-Committee was of the opinion that it should allow for the different use of breast meat, and that it should recommend different nitrogen factors for breast meat and all the other meat. When no information is available on the kind of chicken meat used, a general factor would have to be applied. RECOMMENDATION The Sub-Committee recommends the following average figures for use in the analyses of chicken products: breast meat, 3.9; dark meat, 3-6; whole carcase 3.7. ACKNOWLEDGMENT The Sub-Committee thanks those listed below for their help and communications- Brand & Co. Ltd. Crosse & Blackwell Ltd. N.V.H. Hartog’s Fabrieken Oss, Holland. Harvey’s Belgravia Foods Ltd. J. Lyons & Co. Ltd. The Official Norwegian Quality Control Institute for Canned Fish Products. S. J. Palmer (N/C) Ltd. J. Sainsbury Ltd. C. Shippam Ltd. Unilever Ltd. REFERENCES 1. 2. - , Ibid., 1963, 88, 422. Analytical Methods Committee, Analyst, 1961, 86, 557.