1、BRITISH STANDARD CONFIRMED JUNE1993 BS7037-2: 1989 ISO8197: 1988 Sampling plans for milk and milk products Part2: Inspection by variables UDC 637.1.07:543.8.051+620.1.113BS 7037-2:1989 This British Standard, having been prepared under the directionof the Dairying Standards Policy Committee, waspubli
2、shed under the authorityof the Board of BSIandcomes into effect on 31 October1989 BSI11-1999 The following BSI references relate to the work on this standard: Committee referenceDAC/5 Draft for comment87/50566 DC ISBN 0 580 17333 X Committees responsible for this British Standard The preparation of
3、this British Standard was entrusted by the Dairying Standards Policy Committee (DAC/-) to Technical CommitteeDAC/5, upon which the following bodies were represented: AFRC Institute of Food Research, Reading Laboratory Association of Clinical Pathologists Department of Health and Social Security Ice
4、Cream Alliance Limited Institute of Trading Standards Administration Institution of Environmental Health Officers Intervention Board for Agricultural Produce Milk Marketing Board Milk Marketing Board for Northern Ireland Ministry of Agriculture, Fisheries and Food Royal Association of British Dairy
5、Farmers Society of Chemical Industry Society of Dairy Technology Amendments issued since publication Amd. No. Date of issue CommentsBS7037-2:1989 BSI 11-1999 i Contents Page Committees responsible Inside front cover National foreword ii 1 Scope 1 2 Normative references 1 3 Definitions 1 4 Selection
6、of sampling plan 1 5 Sampling and inspection procedures 2 6 Conformity 2 Annex A (normative) Inspection by variables sampling plans 3 Table A.1 Inspection level1AQL=1% 3 Table A.2 Inspection level1AQL=1,5% 3 Table A.3 Inspection level1AQL=2,5% 4 Table A.4 Inspection level1AQL=4% 4 Table A.5 Inspecti
7、on level1AQL=6,5% 4 Table A.6 Inspection level1AQL=10% 5 Publications referred to Inside back coverBS7037-2:1989 ii BSI 11-1999 National foreword This British Standard has been prepared under the direction of the Dairying Standards Policy Committee and is identical with ISO8197 “Milk and milk produc
8、ts Sampling Inspection by variables”, published by the International Organization for Standardization (ISO). The method has been developed jointly with the International Dairy Federation(IDF) and the Association of Official Analytical Chemists (AOAC) andwill also be published by these organizations.
9、 A British Standard does not purport to include all the necessary provisions of a contract. Users of British Standards are responsible for their correct application. Compliance with a British Standard does not of itself confer immunity from legal obligations. Cross-references International Standard
10、Corresponding British Standard ISO707:1985 BS809:1985 Methods for sampling of milk and milk products (Identical) ISO2859:1974/ Addendum1:1977 BS6000:1972 Guide to the use of BS6001, sampling procedures and tables for inspection by attributes (Identical) ISO3534:1977 BS5532 Statistical terminology Pa
11、rt1:1978 Glossary of terms relating to probability and general terms relating to statistics (Identical) ISO3951:1981 BS6002:1979 Specification for sampling procedures and charts for inspection by variables for percent defective (Technically equivalent) ISO5538:1987 BS7037 Sampling plans for milk and
12、 milk products Part1:1988 Specification for inspection by attributes (Identical) Summary of pages This document comprises a front cover, an inside front cover, pagesi andii, pages1 to6, an inside back cover and a back cover. This standard has been updated (see copyright date) and may have had amendm
13、ents incorporated. This will be indicated in the amendment table on the inside front cover.BS7037-2:1989 BSI 11-1999 1 1 Scope This International Standard describes the basis of sampling plans for the inspection by variables of milk and milk products. It is intended primarily for use under the follo
14、wing conditions: a) where the inspection procedure is to be applied to a continuous series of lots of discrete products, all supplied by one producer using one production process; b) where only a single quality characteristic, x, which must be measurable on a continuous scale, is taken into consider
15、ation (if several such characteristics are of importance, this International Standard applies to each of them separately); c) where production is stable (under statistical control) and the quality characteristic, x, is distributed according to a normal distribution law or a close approximation to th
16、e normal distribution law; d) where a contract or specification defines an upper specification limit U, a lower specification limit L, or both. NOTEThe product is qualified as complying with the requirements of the contract or specification if the measured quality characteristic, x, satisfies one of
17、 the following conditions: Conditions(1) and(2) are called cases with a single specification limit and condition(3) a case with double specification limits. This International Standard does not apply in the case of examination for microbiological defects. 2 Normative references The following standar
18、ds contain provisions which, through reference in this text, constitute provisions of this International Standard. At the time of publication, the editions indicated were valid. All standards are subject to revision, and parties to agreements based on this International Standard are encouraged to in
19、vestigate the possibility of applying the most recent editions of the standards listed below. Members of IEC and ISO maintain registers of currently valid International Standards. ISO707:1985, Milk and milk products Methods of sampling. ISO2859:1974/Add.1:1977, General information on sampling inspec
20、tion, and guide to the use of the ISO2859 tables. ISO3534:1977, Statistics Vocabulary and symbols. ISO3951:1981, Sampling procedures and charts for inspection by variables for percent defective. 3 Definitions For the purposes of this International Standard, the definitions given in ISO3534 apply. 4
21、Selection of sampling plan 4.1 Classification of defects 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 containi
22、ng or referring to the sampling plan. 4.1.1 A critical defect is one that would make the product unacceptable. NOTEInspection by variables should not be used for critical defects. For this category, inspection by attributes should be used (see ISO5538:1987, Milk and milk products Sampling Inspection
23、 by attributes). 4.1.2 A major defect is one 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. Amajor defect would result in the product spoiling or becoming unfit for sale or processing. Examples include a) composition defec
24、t, where this would affect keeping quality; b) contamination with inhibitory substances. 4.1.3 A minor defect 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; for example, a unit, the chemical composition or net content of w
25、hich falls outside, but close to, a specification limit. 4.2 Choice of inspection level and acceptable quality level (AQL) See ISO3951:1981, clause11. Sampling plans for major defects shall be selected from the tables in ISO3951 using an AQL of not more than6,5%. Sampling plans for minor defects sha
26、ll be selected from the tables in ISO3951 using an AQL of not more than10%. xu U . . . (1) or xW L . . . (2) or xu U and xW L . . . (3)BS7037-2:1989 2 BSI 11-1999 5 Sampling and inspection procedures 5.1 Method of sampling Sampling shall be carried out using the methods specified in ISO707. 5.2 Proc
27、edure 5.2.1 Take a sample of n items at random from the lot, in accordance with ISO2859:1974/Add.1:1977, clause15. 5.2.2 Examine each such item separately. A total ofn values will be obtained (x 1 , . . ., x n ). 5.2.3 Calculate the arithmetic mean, , of the n results by means of the formula 5.2.4 C
28、alculate the sample standard deviation, s, by means of the formula where the symbols have the same meaning as in5.2.3. 5.2.5 Calculate the values of Q Land/or Q Uby means of the formulae and NOTEThe value of Q Lis calculated if the measured characteristic has a lower specification limit, Q Uif the m
29、easured characteristic has an upper specification limit, and Q Land Q Uif the measured characteristic has double specification limits. 6 Conformity The lot shall be considered to comply with the requirements if a) in the case of a lower specification limit: Q L W k b) in the case of an upper specifi
30、cation limit: Q U W k c) in the case of a double specification limit: Q L W k and Q U W k where k is the acceptability constant of the sampling plan (see Annex A). The lot shall be deemed not to comply with the requirements if the appropriate condition a), b) or c) is not satisfied. where x i is the
31、 value obtained for the i thitem in the sample of n items (i=1, . . ., n); n is the number of items in the sample. x where is the arithmetic mean calculated in5.2.3; s is the standard deviation calculated in5.2.4; L is the lower specification limit; U is the upper specification limit. Q L xL s - = Q
32、 U Ux s - = xBS7037-2:1989 BSI 11-1999 3 Annex A (normative) Inspection by variables sampling plans This annex sets out six typical sampling plans based on AQLs of1 %,1,5%,2,5 %,4%,6,5% and10% at inspection level1, for normal, tightened and reduced inspection. Switching rules are given in ISO3951. T
33、able A.1 Inspection level1AQL=1% Table A.2 Inspection level1AQL=1,5% Lot size Normal inspection Tightened inspection Reduced inspection n k n k n k Up to 50 51 to90 91 to150 151 to280 281 to500 501 to1200 1201 to3200 3201 to10000 10001 to35000 35001 to 150000 150001 to 500000 500001 and over 4 5 7 1
34、0 15 20 25 35 50 75 100 150 1,45 1,53 1,62 1,72 1,79 1,82 1,85 1,89 1,93 1,98 2,00 2,03 5 5 7 10 15 20 25 35 50 75 100 150 1,65 1,65 1,75 1,84 1,91 1,96 1,98 2,03 2,08 2,12 2,14 2,18 4 4 4 4 5 7 10 15 20 25 35 50 1,34 1,34 1,34 1,34 1,40 1,50 1,58 1,65 1,69 1,72 1,76 1,80 Lot size Normal inspection
35、Tightened inspection Reduced inspection n k n k n k Up to50 51 to90 91 to150 151 to280 281 to500 501 to1200 1201 to3200 3201 to10000 10001 to35000 35001 to 150000 150001 to 500000 500001 and over 4 5 7 10 15 20 25 35 50 75 100 150 1,34 1,40 1,50 1,58 1,65 1,69 1,72 1,76 1,80 1,84 1,86 1,89 4 5 7 10
36、15 20 25 35 50 75 100 150 1,45 1,53 1,62 1,72 1,79 1,82 1,85 1,89 1,93 1,98 2,00 2,03 3 3 3 4 5 7 10 15 20 25 35 50 1,12 1,12 1,12 1,17 1,24 1,33 1,41 1,47 1,51 1,53 1,57 1,61BS7037-2:1989 4 BSI 11-1999 Table A.3 Inspection level1AQL=2,5% Table A.4 Inspection level1AQL=4% Table A.5 Inspection level1
37、AQL=6,5% Lot size Normal inspection Tightened inspection Reduced inspection n k n k n k Up to 25 26 to50 51 to90 91 to150 151 to280 281 to500 501 to1200 1201 to3200 3201 to10000 10001 to35000 35001 to 150000 150001 to 500000 500001 and over 3 4 5 7 10 15 20 25 35 50 75 100 150 1,12 1,17 1,24 1,33 1,
38、41 1,47 1,51 1,53 1,57 1,61 1,65 1,67 1,70 4 4 5 7 10 15 20 25 35 50 75 100 150 1,34 1,34 1,40 1,50 1,58 1,65 1,69 1,72 1,76 1,80 1,84 1,86 1,89 3 3 3 3 4 5 7 10 15 20 25 35 50 0,958 0,958 0,958 0,958 1,01 1,07 1,15 1,23 1,30 1,33 1,35 1,39 1,42 Lot size Normal inspection Tightened inspection Reduce
39、d inspection n k n k n k Up to 25 26 to50 51 to90 91 to150 151 to280 281 to500 501 to1200 1201 to3200 3201 to10000 10001 to35000 35001 to 150000 150001 and over 3 4 5 7 10 15 20 25 35 50 75 100 0,958 1,01 1,07 1,15 1,23 1,30 1,33 1,35 1,39 1,42 1,46 1,48 3 4 5 7 10 15 20 25 35 50 75 100 1,12 1,17 1,
40、24 1,33 1,41 1,47 1,51 1,53 1,57 1,61 1,65 1,67 3 3 3 3 4 5 7 10 15 20 25 35 0,765 0,765 0,765 0,765 0,814 0,874 0,955 1,03 1,09 1,12 1,14 1,18 Lot size Normal inspection Tightened inspection Reduced inspection n k n k n k Up to 25 26 to50 51 to90 91 to150 151 to280 281 to500 501 to1200 1201 to3200
41、3201 to 10000 10001 to 35000 35001 and over 3 4 5 7 10 15 20 25 35 50 75 0,765 0,814 0,874 0,955 1,03 1,09 1,12 1,14 1,18 1,21 1,24 3 4 5 7 10 15 20 25 35 50 75 0,958 1,01 1,07 1,15 1,23 1,30 1,33 1,35 1,39 1,42 1,46 3 3 3 3 4 5 7 10 15 20 25 0,566 0,566 0,566 0,566 0,617 0,675 0,755 0,828 0,886 0,9
42、17 0,936BS7037-2:1989 BSI 11-1999 5 Table A.6 Inspection level1AQL=10% Lot size Normal inspection Tightened inspection Reduced inspection n k n k n k Up to25 26 to50 51 to90 91 to150 151 to280 281 to500 501 to1200 1201 to3200 3 201 to 10000 10001 and over 3 4 5 7 10 15 20 25 35 50 0,566 0,617 0,675
43、0,755 0,828 0,886 0,917 0,936 0,969 1,00 3 4 5 7 10 15 20 25 35 50 0,765 0,814 0,874 0,955 1,03 1,09 1,12 1,14 1,18 1,21 3 3 3 3 4 5 7 10 15 20 0,341 0,341 0,341 0,341 0,393 0,455 0,536 0,611 0,664 0,6956 blankBS7037-2:1989 BSI 11-1999 Publications referred to See national foreword.BS7037-2: 1989 IS
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