1、BSI Standards Publication BS ISO 9622:2013 Milk and liquid milk products Guidelines for the application of mid-infrared spectrometryBS ISO 9622:2013 BRITISH STANDARD National foreword This British Standard is the UK implementation of ISO 9622:2013. It supersedes BS ISO 9622:1999 which is withdrawn.
2、The UK participation in its preparation was entrusted to Technical Committee AW/5, Chemical analysis of milk and milk products. A list of organizations represented on this committee can be obtained on request to its secretary. This publication does not purport to include all the necessary provisions
3、 of a contract. Users are responsible for its correct application. The British Standards Institution 2013. Published by BSI Standards Limited 2013 ISBN 978 0 580 75465 4 ICS 67.100.10 Compliance with a British Standard cannot confer immunity from legal obligations. This British Standard was publishe
4、d under the authority of the Standards Policy and Strategy Committee on 30 September 2013. Amendments issued since publication Date Text affectedBS ISO 9622:2013 Milk and liquid milk products Guidelines for the application of mid- infrared spectrometry Lait et produits laitiers liquides Lignes direc
5、trices pour lapplication de la spectromtrie dans le moyen infrarouge INTERNATIONAL STANDARD Second edition 2013-09-15 ISO and IDF 2013 Reference numbers ISO 9622:2013(E) IDF 141:2013(E) ISO 9622 IDF 141BS ISO 9622:2013ISO 9622:2013(E) IDF 141:2013(E) ii ISO and IDF 2013 All rights reserved COPYRIGHT
6、 PROTECTED DOCUMENT ISO/IDF 2013 All rights reserved. Unless otherwise specified, no part of this publication may be reproduced or utilized otherwise in any form or by any means, electronic or mechanical, including photocopying, or posting on the internet or an intranet, without prior written permis
7、sion. Permission can be requested from either ISO or IDF at the respective address below or ISOs member body in the country of the requester. ISO copyright office International Dairy Federation Case postale 56 CH-1211 Geneva 20 Silver Building Bd Auguste Reyers 70/B B-1030 Brussels Tel. + 41 22 749
8、01 11 Tel. + 32 2 733 98 88 Fax + 41 22 749 09 47 Fax + 32 2 733 04 13 E-mail copyrightiso.org E-mail infofil-idf.org Web www.iso.org Web www.fil-idf.org Published in SwitzerlandBS ISO 9622:2013ISO 9622:2013(E) IDF 141:2013(E) ISO and IDF 2013 All rights reserved iii Contents Page Foreword iv 1 Scop
9、e . 1 2 Normative references 1 3 T erms and definitions . 1 4 Principle 2 5 Principal characteristics of infrared instruments . 2 6 Factors affecting the measurements 2 6.1 Instrument factors . 2 6.2 Physico-chemical and biological factors . 5 7 Calibration of the instrument . 8 7.1 Objective . 8 7.
10、2 Spectrum calibration models 8 7.3 Core settings 9 7.4 Checking the slope and intercept 9 8 Sampling .10 9 Determination 10 10 Checking daily short-term stability of the instrument 10 10.1 General 10 10.2 Preparation and storage of control samples 10 10.3 Analysis of control samples.11 10.4 Monitor
11、ing the analytical procedure 11 10.5 Re-adjustment of instrument settings .11 11 Precision 12 11.1 Repeatability 12 11.2 Intra-laboratory reproducibility .12 11.3 Reproducibility 12 12 Test report 13 Bibliography .14BS ISO 9622:2013ISO 9622:2013(E) Foreword ISO (the International Organization for St
12、andardization) is a worldwide 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 rig
13、ht to be represented on that 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. The procedure
14、s used to develop this document and those intended for its further maintenance are described in the ISO/IEC Directives, Part 1. In particular the different approval criteria needed for the different types of ISO documents should be noted. This document was drafted in accordance with the editorial ru
15、les of the ISO/IEC Directives, Part 2. www.iso.org/directives Attention is drawn to the possibility that some of the elements of this document may be the subject of patent rights. ISO shall not be held responsible for identifying any or all such patent rights. Details of any patent rights identified
16、 during the development of the document will be in the Introduction and/or on the ISO list of patent declarations received. www.iso.org/patents Any trade name used in this document is information given for the convenience of users and does not constitute an endorsement. The committee responsible for
17、 this document is ISO/TC 34, Food products, Subcommittee SC 5, Milk and milk products, and the International Dairy Federation (IDF). It is being published jointly by ISO and IDF. This second edition of joint ISO 9622|IDF 141 cancels and replaces the first edition (ISO 9622:1999), which has been tech
18、nically revised. IDF 141:2013(E) iv ISO and IDF 2013 All rights reservedBS ISO 9622:2013ISO 9622:2013(E) Foreword IDF (the International Dairy Federation) is a non-profit organization representing the dairy sector worldwide. IDF membership comprises National Committees in every member country as wel
19、l as regional dairy associations having signed a formal agreement on cooperation with IDF. All members of IDF have the right to be represented on the IDF Standing Committees carrying out the technical work. IDF collaborates with ISO in the development of standard methods of analysis and sampling for
20、 milk and milk products. The main task of Standing Committees is to prepare International Standards. Draft International Standards adopted by the Standing Committees are circulated to the National Committees for endorsement prior to publication as an International Standard. Publication as an Interna
21、tional Standard requires approval by at least 50 % of IDF National Committees casting a vote. Attention is drawn to the possibility that some of the elements of this document may be the subject of patent rights. IDF shall not be held responsible for identifying any or all such patent rights. Any tra
22、de name used in this document is information given for the convenience of users and does not constitute an endorsement. ISO 9622|IDF 141 was prepared by the International Dairy Federation (IDF) and Technical Committee ISO/TC 34, Food products, Subcommittee SC 5, Milk and milk products. It is being p
23、ublished jointly by IDF and ISO. All work was carried out by an ISO-IDF Project Group on Guidance on the application of mid-infrared spectrometry, of the Standing Committee on Statistics and Automation (SCSA), under the aegis of its project leaders, Mr. P. Sauv (CA) and Mr. H. van den Bijgaart (NL).
24、 This second edition of joint ISO 9622|IDF 141 cancels and replaces IDF 141C:2000, which has been technically revised. IDF 141:2013(E) ISO and IDF 2013 All rights reserved vBS ISO 9622:2013BS ISO 9622:2013Milk and liquid milk products Guidelines for the application of mid-infrared spectrometry 1 Sco
25、pe This International Standard gives guidelines for the quantitative compositional analysis of milk and liquid milk products, such as raw milk, processed milk, cream and whey, by measurement of the absorption of mid-infrared radiation. Additional built-in instrument features, such as a conductivity
26、sensor, can improve the performance in the determination of compositional parameters and allow for the estimation of other parameters. The guidelines specified are applicable to the analysis of cows milk. The guidelines are also applicable to the analysis of milk of other species (goat, ewe, buffalo
27、, etc.) and derived liquid milk products, provided adequate calibrations are generated for each application and adequate control procedures are in place. The application is limited to lower viscosity products that can be pumped through the flow system of the analyser and to analytes that do not resu
28、lt in optical saturation at the specific wavelengths being utilized. 2 Normative references The following documents, in whole or in part, are normatively referenced in this document and are indispensable to its application. For dated references, only the edition cited applies. For undated references
29、, the latest edition of the referenced document (including any amendments) applies. ISO 8196|IDF 128 (all parts), Milk Definition and evaluation of the overall accuracy of indirect methods of milk analysis ISO 8968-1|IDF 20-1, Milk Determination of nitrogen content Part 1: Kjeldahl method ISO 8968-2
30、|IDF 20-2, Milk Determination of nitrogen content Part 2: Block-digestion method (Macro method) ISO 8968-5|IDF 20-5, Milk Determination of nitrogen content Part 5: Determination of protein- nitrogen content NOTE Other normative documents can apply depending on the specific application or calibration
31、 of the automated analyser. 3 T erms a nd definiti ons For the purposes of this document, the terms and definitions given in ISO 8196|IDF 128 (all parts), and the following apply. 3.1 spectral calibration spectrum calibration model calibration based on combination of absorbance signals at several (2
32、) wavelengths in the mid-infrared region or signals from other sensors, mathematically optimized to arrive at the best estimate for the parameter of interest 3.2 slope and intercept calibration simple linear regression coefficients as established from a least-squares regression of optimized instrume
33、nt readings against results as obtained with physico-chemical reference methods INTERNATIONAL ST ANDARD ISO 9622:2013(E) IDF 141:2013(E) ISO and IDF 2013 All rights reserved 1BS ISO 9622:2013ISO 9622:2013(E) 4 Principle After pretreatment and homogenization, where required, the sample is measured wi
34、th an infrared spectrometer that records the quantity of radiation absorbed in transmittance at specific wavelengths in the mid-infrared region. The spectral data are transformed into estimates of constituent concentrations or other physico-chemical parameters through calibration models developed on
35、 representative samples from the population to be tested. For some parameters, i.e. freezing point equivalents, signals from additional installed sensors may be fed to the calibration model. 5 Principal characteristics of infrared instruments The signals at the relevant wavelengths may be produced u
36、sing either a Fourier-transformed interferogram or by using optical filters. Instruments and applied calibration models may differ with respect to the number of specific wavelengths used in estimating the parameters of interest. An infrared instrument is a proprietary apparatus which, when used unde
37、r the conditions defined in this International Standard, provides estimates of compositional and other parameters in milk and liquid milk products. 6 Factors affecting the measurements 6.1 Instrument factors 6.1.1 Repeatability To check instrument repeatability, analyse a uniform representative samp
38、le a minimum of 12 times in succession. The first two replicate results are discarded to minimize carry-over effects. The calculated repeatability should meet with the repeatability limits for the concerned parameter and sample matrix. 6.1.2 Zero stability To monitor zero stability, a blank sample (
39、water or zero solution) is analysed periodically during routine use of the instrument. Drift should be relatively small and random with respect to direction (), such that cumulative drift is minimal. A plot of the zero drift vs time is an effective way to track instrument stability. NOTE Certain ins
40、truments are factory set to auto-correct the zero at regular intervals. It is intended that operators review these automatic corrections to ensure that cumulative drift is not excessive. 6.1.3 Homogenization To check the efficiency of the homogenizer, make two consecutive analyses, firstly with an u
41、nhomogenized whole milk sample, and secondly with the same whole milk sample after it has been homogenized through the instruments homogenizer. When the average of five replicate fat readings is found, the difference among these five replicate fat readings shall not exceed 0,04 % for a milk sample c
42、ontaining a mass fraction of 4,0 % of milk fat. To calculate the appropriate pass/fail criteria for milk fat concentrations other than 4,0 %, multiply the actual fat content by 0,01 to obtain the new criteria. NOTE 1 This procedure is only applicable to instruments in which the homogenized discharge
43、 can be isolated and collected. NOTE 2 For applications involving sample matrices with higher levels of fat (i.e. raw cream), it is advisable to check homogenization efficiency with a representative high fat sample. Specific parameters for homogenizer performance depend upon the matrix. IDF 141:2013
44、(E) 2 ISO and IDF 2013 All rights reservedBS ISO 9622:2013ISO 9622:2013(E) NOTE 3 Instrument readings for every milk fat component (e.g. individual fatty acids or groups of fatty acids) is dependent on the effectiveness of homogenization. Different wavelengths used in calibration models result in un
45、equal sensitivity to homogenizer efficiency and possibly larger relative effects than for fat. When measuring such milk fat components, it is intended that the homogenizer efficiency test be performed for these components, and the difference is not intended to exceed the limit of repeatability for t
46、he component. CAUTION The results of this test can be misleading, as an instrument in which the homogenizer d o e s n o t w o r k a t a l l g i v e s v e r y l i t t l e d i f f e r e n c e b e t w e e n t h e f i r s t a n d t h e s e c o n d r u n . An alternative procedure is to obtain an unhomog
47、enized as well as a homogenized portion of the same milk, either by collecting raw and processed milk from the same tank at a dairy plant or by producing smaller volumes by means of a bench-top or pilot-plant homogenizer. Then measure both the unhomogenized and the same homogenized milk and compare
48、the difference in results to the above- mentioned pass/fail criterion. The assumption is that the homogenization efficiency of the external homogenizer is good. That can be verified by particle size analysis of the homogenized milk. A reasonable fat globule size distribution is characterized by a d
49、(0,9) of 1,4 m to 1,5 m d (0,9) means that 90 % of the milk fat globules has a diameter of less than d. 17 Some instruments allow the user to monitor a homogenization index value to track the performance of the homogenizer. The manufacturers guidelines should be followed. Monitoring of instrument repeatability can also provide valuable information with respect to the state of the homogenizer. If repeatability on homogenized milk is satisfactory, whereas the repeatability on raw milk is poor (more than twice the variati
