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1、 Reference numbers ISO 5538:2004(E) IDF 113:2004(E) ISO and IDF 2004 INTERNATIONAL STANDARD ISO 5538 IDF 113 Second edition 2004-12-01 Milk and milk products Sampling Inspection by attributes Lait et produits laitiers chantillonnage Contrle par attributs Copyright International Organization for Stan
2、dardization Provided by IHS under license with ISO Licensee=Hong Kong Polytechnic Univ/9976803100 Not for Resale, 04/17/2007 10:12:06 MDTNo reproduction or networking permitted without license from IHS -,-,- ISO 5538:2004(E) IDF 113:2004(E) PDF disclaimer This PDF file may contain embedded typefaces
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5、meters were optimized for printing. Every care has been taken to ensure that the file is suitable for use by ISO member bodies and IDF national committees. In the unlikely event that a problem relating to it is found, please inform the ISO Central Secretariat at the address given below. ISO and IDF
6、2004 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, including photocopying and microfilm, without permission in writing from either ISO or IDF at the respective address below. ISO copyr
7、ight office International Dairy Federation Case postale 56 CH-1211 Geneva 20 Diamant Building Boulevard Auguste Reyers 80 B-1030 Brussels Tel. + 41 22 749 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
8、-idf.org Published in Switzerland ii ISO and IDF 2004 All rights reserved Copyright International Organization for Standardization Provided by IHS under license with ISO Licensee=Hong Kong Polytechnic Univ/9976803100 Not for Resale, 04/17/2007 10:12:06 MDTNo reproduction or networking permitted with
9、out license from IHS -,-,- ISO 5538:2004(E) IDF 113:2004(E) ISO and IDF 2004 All rights reserved iii Contents Forewordiv Introduction .vi 1 Scope1 2 Normative references .1 3 Terms and definitions.1 4 Sampling plans2 5 Selection of sampling plan.2 5.1 Classification of defects.2 5.2 Choice of inspec
10、tion level and AQL3 6 Records4 7 Selection of units 4 Annex A (normative) Statistical theory 11 Annex B (normative) Critical defects .12 Annex C (informative) Drawing of samples .14 Bibliography .20 Copyright International Organization for Standardization Provided by IHS under license with ISO Licen
11、see=Hong Kong Polytechnic Univ/9976803100 Not for Resale, 04/17/2007 10:12:06 MDTNo reproduction or networking permitted without license from IHS -,-,- ISO 5538:2004(E) IDF 113:2004(E) iv ISO and IDF 2004 All rights reserved Foreword ISO (the International Organization for Standardization) is a worl
12、dwide 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
13、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. International Standards are drafted i
14、n accordance with the rules given in the ISO/IEC Directives, Part 2. The main task of technical committees is to prepare International Standards. Draft International Standards adopted by the technical committees are circulated to the member bodies for voting. Publication as an International Standard
15、 requires approval by at least 75 % of the member bodies casting a vote. 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. ISO 5538IDF 113 was prepared
16、 by Technical Committee ISO/TC 34, Food products, Subcommittee SC 5, Milk and milk products, and the International Dairy Federation (IDF), in collaboration with AOAC International. It is being published jointly by ISO and IDF and separately by AOAC International. This edition of ISO 5538IDF 113 canc
17、els and replaces ISO 5538:1987, of which it constitutes a minor revision. Only editorial changes have been made. Copyright International Organization for Standardization Provided by IHS under license with ISO Licensee=Hong Kong Polytechnic Univ/9976803100 Not for Resale, 04/17/2007 10:12:06 MDTNo re
18、production or networking permitted without license from IHS -,-,- ISO 5538:2004(E) IDF 113:2004(E) ISO and IDF 2004 All rights reserved v Foreword IDF (the International Dairy Federation) is a worldwide federation of the dairy sector with a National Committee in every member country. Every National
19、Committee has the right to be represented on the IDF Standing Committees carrying out the technical work. IDF collaborates with ISO and AOAC International in the development of standard methods of analysis and sampling for milk and milk products. Draft International Standards adopted by the Action T
20、eams and Standing Committees are circulated to the National Committees for voting. Publication as an International Standard requires approval by at least 50 % of the National Committees casting a vote. ISO 5538IDF 113 was prepared by Technical Committee ISO/TC 34, Food products, Subcommittee SC 5, M
21、ilk and milk products, and the International Dairy Federation (IDF), in collaboration with AOAC International. It is being published jointly by ISO and IDF and separately by AOAC International. All work was carried out by the Joint ISO/IDF/AOAC Group of Experts, Selection of samples (E26), under the
22、 aegis of its chairman, Mr D.C. Bettes (GB). This edition of ISO 5538IDF 113 cancels and replaces IDF 113A:1990. Only editorial changes have been made. Copyright International Organization for Standardization Provided by IHS under license with ISO Licensee=Hong Kong Polytechnic Univ/9976803100 Not f
23、or Resale, 04/17/2007 10:12:06 MDTNo reproduction or networking permitted without license from IHS -,-,- ISO 5538:2004(E) IDF 113:2004(E) vi ISO and IDF 2004 All rights reserved Introduction The sampling theory used in this International Standard is based on classifying a unit as “good” or “defectiv
24、e”. A “good” unit is one which meets the requirements of a specification, while a “defective” unit is one which does not. It is essential that the sample be taken at random. If it is not, the sampling plans will not give the stated protection. See Annex A. Copyright International Organization for St
25、andardization Provided by IHS under license with ISO Licensee=Hong Kong Polytechnic Univ/9976803100 Not for Resale, 04/17/2007 10:12:06 MDTNo reproduction or networking permitted without license from IHS -,-,- INTERNATIONAL STANDARD ISO 5538:2004(E) IDF 113:2004(E) ISO and IDF 2004 All rights reserv
26、ed 1 Milk and milk products Sampling Inspection by attributes 1 Scope 1.1 This International Standard specifies sampling plans for the inspection by attributes of milk and milk products. It is intended to be used to choose a sample size for any situation where it is required to measure the conformit
27、y to a specification of a lot of a dairy product by examination of a representative sample. 1.2 This International Standard is applicable to the sampling of all milk products submitted in discrete lots, irrespective of whether the lots are from the same production. The acceptance or otherwise of any
28、 lot is a matter for the parties to a contract and is outside the scope of this International Standard. 1.3 This International Standard is intended to be used in all cases where attribute sampling plans are required for a dairy product, except that if specific compositional standards, specifications
29、 or contracts include different sampling schemes, those schemes are to be used. 1.4 This International Standard is not applicable to sampling for microbiological defects, unless otherwise agreed by the interested parties. NOTE Methods of sampling for milk and milk products are given in ISO 707. 2 No
30、rmative references The following referenced documents are indispensable for the application of this document. For dated references, only the edition cited applies. For undated references, the latest edition of the referenced document (including any amendments) applies. ISO 2859-1:1999, Sampling proc
31、edures for inspection by attributes Part 1: Sampling schemes indexed by acceptance quality limit (AQL) for lot-by-lot inspection ISO 3534-1, Statistics Vocabulary and symbols Part 1: Probability and general statistical terms ISO 3534-2, Statistics Vocabulary and symbols Part 2: Applied statistics 3
32、Terms and definitions For the purposes of this document, the terms and definitions given in ISO 3534-1, ISO 3534-2 and the following apply. 3.1 acceptance quality limit AQL quality level that is the worst tolerable process average when a continuing series of lots is submitted for acceptance sampling
33、 ISO 2859-1:1999, definition 3.1.29 Copyright International Organization for Standardization Provided by IHS under license with ISO Licensee=Hong Kong Polytechnic Univ/9976803100 Not for Resale, 04/17/2007 10:12:06 MDTNo reproduction or networking permitted without license from IHS -,-,- ISO 5538:20
34、04(E) IDF 113:2004(E) 2 ISO and IDF 2004 All rights reserved 4 Sampling plans ISO 2859-1 describes plans for use in all situations, and gives an account of the theoretical background to the sampling tables. The plans are indexed by batch or lot size and acceptance quality limit (AQL). 5 Selection of
35、 sampling plan 5.1 Classification of defects 5.1.1 General Before selection of a sampling plan, the contract or specification shall clearly define all critical, major and minor defects in such a way that they are unambiguously understood by all users of the contract, specification or document contai
36、ning or referring to the sampling plan. 5.1.2 Critical defect This is a defect that would make the product unacceptable. For the purposes of this International Standard, critical defects relate to the presence of toxic contaminants at a critically high level. Examples include heavy metals and pestic
37、ide residues. In this case, the method to be adopted shall be that described in Annex B. It is necessary to decide on an acceptable risk of not detecting a certain percentage of defectives, where a defective is a unit which contains more than the critical level of the contaminant. It is impossible t
38、o guarantee freedom from contamination. 5.1.3 Major defect This is a defect that is likely to make the product unfit for use; i.e. in the case of milk and milk products, unfit for sale to the consumer. A major defect would result in the product spoiling or becoming unfit for sale or processing. Exam
39、ples include a) composition defect, where this would affect keeping quality, b) contamination with inhibitory substances, c) integrity of packaging, and d) visible contamination with dirt. Sampling plans for major defects shall be selected from the Tables using an AQL of not more than 6,5 %. 5.1.4 M
40、inor defect This is a failure to comply with a specification, but which does not make the unit unfit for use and sale, nor cause it to spoil. Examples include a) a unit, the chemical composition or net content of which falls outside, but close to, a specification limit, and b) small abnormalities in
41、 appearance. Sampling plans for minor defects shall be selected from Tables 1 to 24 using an AQL of not more than 10 %. Copyright International Organization for Standardization Provided by IHS under license with ISO Licensee=Hong Kong Polytechnic Univ/9976803100 Not for Resale, 04/17/2007 10:12:06 M
42、DTNo reproduction or networking permitted without license from IHS -,-,- ISO 5538:2004(E) IDF 113:2004(E) ISO and IDF 2004 All rights reserved 3 5.2 Choice of inspection level and AQL 5.2.1 The sampling plan shall be selected from Tables 1 to 24, using the lot size and the agreed AQL. In these Table
43、s, n is the sample size, Ac is the acceptance number, and Re is the rejection number. EXAMPLE For a sample size of n = 13, Ac = 0 and Re = 1, this means that if a sample of 13 units contains no defectives, the lot shall be accepted; if the sample contains 1 defective, the lot shall be rejected. Tabl
44、es 1 to 20 are derived from ISO 2859-1 and refer to Inspection Levels I, S-4, S-3, S-2 and S-1. Inspection Level I is preferred. Using any of the S plans will result in increased risks, and they shall not be used without first checking that the associated risk is acceptable. Details of these risks a
45、re given in 5.2.2. 5.2.2 Inspection Levels S-4, S-3, S-2 and S-1 may be used where relatively small sample sizes are necessary and large sample risks may or must be tolerated. As a consequence of using these special levels, there is an increased probability of making a wrong decision. First, the con
46、sumers risk increases. This is illustrated in Tables 21 to 24. Table 21 refers to plans with an AQL of 2,5 %, Table 22 to an AQL of 4,0 %, Table 23 to an AQL of 6,5 % and Table 24 to an AQL of 10 %. Each Table contains the sample size (n) and the appropriate lot size at the separate inspection level
47、s, maximum number of defective units permitted in the sample, i.e. the acceptance number (Ac), minimum number of defective units required in the sample to reject the lot, i.e. the rejection number (Re), and the limiting quality (LQ). If the sample size is small, the LQ is high; if the sample size in
48、creases, the LQ is reduced at the same AQL. For example, in Table 6, the inspection plan in which the sample size is 5 and LQ = 45 % appears in all the inspection levels but only at S-1 level can all lot sizes be inspected. At the S-4 and I Inspection Levels, the sample size of 5 may only be taken when the lot size does not exceed 150. The fact that the consumers risk (and at the same time the LQ) becomes smaller as the size of the inspected lot becomes gre