ISO-9622-1999.pdf
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1、A Reference number ISO 9622:1999(E) INTERNATIONAL STANDARD ISO 9622 First edition 1999-11-15 Whole milk Determination of milkfat, protein and lactose content Guidance on the operation of mid-infrared instruments Lait entier Dtermination des teneurs en matire grasse laitire, en protines et en lactose
2、 Lignes directrices pour lutilisation des appareils de dosage par absorption dans le moyen infrarouge -,-,- ISO 9622:1999(E) ISO 1999 All rights reserved. Unless otherwise specified, no part of this publication may be reproduced or utilized in any form or by any means, electronic or mechanical, incl
3、uding photocopying and microfilm, without permission in writing from the publisher. International Organization for Standardization Case postale 56 CH-1211 Genve 20 Switzerland Internetisoiso.ch Printed in Switzerland ii Contents 1 Scope1 2 Normative references1 3 Terms and definitions .2 4 Principle
4、2 5 Principal characteristics of infrared instruments.2 6 Factors affecting the accuracy of measurement3 6.1 Instrument factors 3 6.2 Physicochemical and biological factors 5 7 Calibration of the instrument7 7.1 Objective7 7.2 Checking the initial calibration for fat, protein and lactose .7 7.3 Main
5、taining calibration and confirmation of calibration validity.8 8 Sampling.8 9 Uniformity of test samples8 10 Determination.8 11 Checking daily short-term stability of the instrument .9 11.1 General.9 11.2 Preparation and storage of sub-samples.9 11.3 Analysis of control samples9 11.4 Monitoring the
6、analytical procedure.9 11.5 Re-adjustment of calibration.11 12 Precision and accuracy.11 12.1 Repeatability11 -,-,- ISOISO 9622:1999(E) iii 12.2 Intralaboratory reproducibility 12 12.3 Accuracy12 13 Test report12 Annex A (informative) Procedure for setting and evaluating linearity on a mass/volume b
7、asis13 Annex B (informative) Control and adjustment of correction factors .15 Annex C (informative) Procedure for calibration of infrared milk analysers using modified milk samples24 Bibliography27 ISO 9622:1999(E) ISO iv Foreword ISO (the International Organization for Standardization) is a worldwi
8、de federation of national standards bodies (ISO member bodies). The work of preparing International Standards is normally carried out through ISO technical committees. Each member body interested in a subject for which a technical committee has been established has the right to be represented on tha
9、t committee. International organizations, governmental and non-governmental, in liaison with ISO, also take part in the work. ISO collaborates closely with the International Electrotechnical Commission (IEC) on all matters of electrotechnical standardization. International Standards are drafted in a
10、ccordance with the rules given in the ISO/IEC Directives, Part 3. Draft International Standards adopted by the technical committees are circulated to the member bodies for voting. Publication as an International Standard requires approval by at least 75 % of the member bodies casting a vote. Interna
11、tional Standard ISO 9622 was prepared by Technical Committee ISO/TC 34, Agricultural food products, Subcommittee SC 5, Milk and milk products, in collaboration with the International Dairy Federation (IDF) and AOAC International, and will also be published by these organizations. Annexes A, B and C
12、of this International Standard are for information only. INTERNATIONAL STANDARD ISOISO 9622:1999(E) 1 Whole milk Determination of milkfat, protein and lactose content Guidance on the operation of mid-infrared instruments 1 Scope This International Standard describes the operating conditions for inst
13、ruments used for the determination of fat, protein and lactose content of ex-farm milk, based upon the measurement of the absorption of mid-infrared radiation at wavelengths which are representative of each component analysed. NOTE 1 In practice, these measurements are made using commercial automati
14、c or semi-automatic instruments defined in clause 5 and called “infrared instruments“ in this International Standard. Any model of instrument which does not comply with the principle of analysis given in this International Standard or which incorporates modifications that may alter the principal cha
15、racteristics of the apparatus (repeatability, accuracy, conditions of use), as well as the means of adjusting the calibration, will require a separate specific standard. NOTE 2Not all instruments allow determination of the lactose content. Moreover, some instruments allow direct measurement of the w
16、ater content. The total solids content can be estimated by adding together the fat, protein and lactose contents, a constant being used to correct for the salt content. The method described is applicable to the determination of the fat, protein and, as appropriate, lactose content of ex-farm milk. T
17、he method is also applicable to the analysis of milk of other species (goat, ewe, buffalo, etc.) and processed milk provided a specific calibration of the instrument (see clause 7) is made. 2 Normative references The following normative documents contain provisions which, through reference in this t
18、ext, constitute provisions of this International Standard. For dated references, subsequent amendments to, or revisions of, any of these publications do not apply. However, parties to agreement based on this International Standard are encouraged to investigate the possibility of applying the most re
19、cent editions of the normative documents indicated below. For undated references, the latest edition of the normative document referred to applies. Members of ISO and IEC maintain registers of currently valid International Standards. ISO 1211, Milk Determination of fat content Gravimetric method (Re
20、ference method). ISO 5765-1, Dried milk, dried ice-mixes and processed cheese Determination of lactose content Part 1: Enzymatic method utilizing the glucose moiety of the lactose. ISO 5765-2, Dried milk, dried ice-mixes and processed cheese Determination of lactose content Part 2: Enzymatic method
21、utilizing the galactose moiety of the lactose. ISO 8968-1, Milk Determination of nitrogen content Part 1: Kjeldahl method. ISO 8968-2, Milk Determination of nitrogen content Part 2: Block-digestion method (Macro method). ISO 8968-4, Milk Determination of nitrogen content Part 4: Determination of non
22、-protein nitrogen content. ISO 8968-5, Milk Determination of nitrogen content Part 5: Determination of protein-nitrogen content. -,-,- ISO 9622:1999(E) ISO 2 3 Terms and definitions For the purposes of this International Standard, the following terms and definitions apply. 3.1 infrared instrument pr
23、oprietary apparatus which, when used under the conditions defined in this International Standard, estimates the mass fraction of fat, protein and lactose in whole milk 3.2 fat, protein and lactose content mass fraction of substances determined using the method specified in this International Standar
24、d NOTE The fat, protein and lactose contents are expressed as mass fractions, in percent formerly given as % (m/m). 4 Principle After homogenization of the milk sample, measurement with an infrared spectrometer of the quantity of radiation absorbed by: the carbonyl groups of the ester bonds of the g
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