1、INTERNATIONAL STANDARD INTERNATIONAL ORGANIZATION FOR STANDARDIZATION ORGANISATION INTERNATIONALE DE NORMALISATION MEXAYHAPOAHAR OPTAHM3Al#lR no CTAHAAPTMSAUMM Milk and milk prodi by variables cts - Sa npling - Inspection Lait et produits laitiers - Echantillonnage - Contrle par mesures IS0 8197 Fir
2、st edition 1988-11-01 Reference number IS0 8197 : 1988 (E) Copyright International Organization for Standardization Provided by IHS under license with ISONot for ResaleNo reproduction or networking permitted without license from IHS-,-,- IS0 8197 : 1988 (E) Foreword IS0 (the International Organizati
3、on for Standardization) is a worldwide federation of national standards bodies (IS0 member bodies). The work of preparing International Standards is normally carried out through IS0 technical committees. Each member body interested in a subject for which a technical committee has been established ha
4、s the right to be represented on that committee. International organizations, govern- mental and non-governmental, in liaison with ISO, also take part in the work. IS0 collaborates closely with the International Electrotechnical Commission (IEC) on all matters of electrotechnical standardization. Dr
5、aft International Standards adopted by the technical committees are circulated to the member bodies for approval before their acceptance as International Standards by the IS0 Council. They are approved in accordance with IS0 procedures requiring at feast 75 % approval by the member bodies voting. In
6、ternational Standard IS0 8197 was prepared by Technical Committee ISO/TC 34, Agricultural food products, in collaboration with the International Dairy Federation (IDFI and the Association of Official Analytical Chemists (AOAC) and will also be published by these organizations. Annex A forms an integ
7、ral part of this International Standard. O International Organization for Standardization, 1988 Printed in Switzerland Copyright International Organization for Standardization Provided by IHS under license with ISONot for ResaleNo reproduction or networking permitted without license from IHS-,-,-IS0
8、 8197 : 1988 (EI Introduction Inspection by variables is a method which consists in measuring a quantitative characteristic for each item of a sample taken from a population. The acceptability of the population is established statistically from the number of items in the sample that meet specified r
9、equirements. iii Copyright International Organization for Standardization Provided by IHS under license with ISONot for ResaleNo reproduction or networking permitted without license from IHS-,-,-INTERNATIONAL STANDARD IS0 8197 : 1988 (E) by variables 1 Scope This International Standard describes the
10、 basis of sampling plans for the inspection by variables of milk and milk products. It is intended primarily for use under the following 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 product
11、ion process; b) where only a single quality characteristic, x, which must be measurable on a continuous scale, is taken into consideration (if several such characteristics are of impor- tance, this International Standard applies to each of them separately); c) where production is stable (under stati
12、stical control) and the quality characteristic, x, is distributed according to a normal distribution law or a close approximation to the normal distribution law; d) where a contract or specification defines an upper specification limit U, a lower specification limit L, or both. NOTE - The product is
13、 qualified as complying with the requirements of the contract or specification if the measured quality characteristic, x, satisfies one of the following conditions : xL . . I (2) or xL . . . (3) Conditions (1 I and (2) are called cases with a single specification limit and condition (3) a case with
14、double specification limits. This International Standard does not apply in the case of examination for microbiological defects. 2 Normative references The following standards contain provisions which, through reference in this text, constitute provisions of this International Standard. At the time o
15、f publication, the editions indicated were valid. All standards are subject to revision, and parties to Ing - Inspection agreements based on this International Standard are encour- aged to investigate the possibility of applying the most recent editions of the standards listed below. Members of IEC
16、and IS0 maintain registers of currently valid International Standards. IS0707 : 1985, Milk and milk products - Methods of sampling. IS0 2859 : 1974lAdd.l : 1977, General information on sam- pling inspection, and guide to the use of the IS0 2859 tables. IS0 3534 : 1977, Statistics - Vocabulary and sy
17、mbols. IS0 3951 : 1981, Sampling procedures and charts for inspec- tion by variables for percent defective. 3 Definitions For the purposes of this International Standard, the definitions given in IS0 3534 apply. L and milk products - Samp 4 Selection of sampling plan 4.1 Classification of defects Be
18、fore selection of a sampling plan, the contract or specifica- tion 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 containing or referring to the sampling plan. 4.1.T A critical de
19、fect is one that would make the product unacceptable. NOTE - Inspection by variables should not be used for critical defects. For this category, inspection by attributes should be used (see IS0 5538 : 1987, Milkandmilk products - Sampling - Inspection by . attributes). 4.1.2 A major defect is one th
20、at is likely to make the product unfit for use, .e. in the case of milk and milk products, unfit for 1 Copyright International Organization for Standardization Provided by IHS under license with ISONot for ResaleNo reproduction or networking permitted without license from IHS-,-,-IS0 8197 : 1988 (E)
21、 sale to the consumer. A major defect would result in the pro- duct spoiling or becoming unfit for sale or processing. Examples include a) composition defect, where this would affect keeping quality; b) contamination with inhibitory substances. 4.1.3 A minor defect is a failure to comply with a spec
22、ifica- tion, but which does not make the unit unfit for use and sale, nor cause it to spoil; for example, a unit, the chemical composi- tion or net content of which falls outside, but close to, a specification limit. 4.2 Choice of inspection level and acceptable quality level (AQL) See IS0 3951 : 19
23、81, clause 11. Sampling plans for major defects shall be selected from the tables in IS0 3951 using an AQL of not more than 6,5 %. Sampling plans for minor defects shall be selected from the tables in IS0 3951 using an AQL of not more than 10 %. 5 Sampling and inspection procedures 5.1 Method of sam
24、pling Sampling shall be carried out using the methods specified in IS0 707. 5.2 Procedure 5,2.1 Take a sample of n items at random from the lot, in accordance with IS0 2859 : 1974/Add.l : 1977, clause 15. 5.2.2 Examine each such item separately. A total of n values will be obtained Cxll . . ., xn).
25、5.2.3 Calculate the arithmetic mean, XI of the n results by means of the formula =+Yi 1“ n i= 1 where xi is the value obtained for the ifh item in the sample of n items (i = 1, ., n); n is the number of items in the sample. 5.2.4 Calculate the sample standard deviation, s, by means of the formula wh
26、ere the symbols have the same meaning as in 5.2.3. 5.2.5 Calculate the values of QL and/or Qu by means of the formulae i-L QL = 7 and U-X Qu=y where X is the arithmetic mean calculated in 5.2.3; s is the standard deviation calculated in 5.2.4; L is the lower specification limit; U is the upper speci
27、fication limit. NOTE - The value of QL is calculated if the measured characteristic has a lower specification limit, Quif the measured characteristic has an upper specification limit, and QL and Qu if the measured characteristic has double specification limits. 6 Conformity The lot shall be consider
28、ed to comply with the requirements if a) in the case of a lower specification limit : QL k b) in the case of an upper specification limit : Qu k c) in the case of a double specification limit : QL k and Qu k where k is the acceptability constant of the sampling plan (see annex A). The lot shall be d
29、eemed not to comply with the requirements if the appropriate condition a), b) or c) is not satisfied. 2 Copyright International Organization for Standardization Provided by IHS under license with ISONot for ResaleNo reproduction or networking permitted without license from IHS-,-,-Annex A ( norma ti
30、ve) n 4 5 7 10 15 20 25 35 50 75 100 150 Inspection by variables sampling plans k 1,45 1 .= 1,62 1,72 1.79 1,82 1,85 1 ,= 1,93 1,98 2,oo 2.03 This annex sets out six typical sampling plans based on AQLs of 1 %, 1,5 %, 2,5 %, 4 %, 6,5 % and 10 % at inspection level 1, for normal, tightened and reduce
31、d inspection. Switching rules are given in IS0 3952. n 4 5 7 10 15 20 25 35 50 75 Table A.l - Inspection level 1 - AQL = 1 YO k 1.34 1,40 1.50 1 ,= 1,65 1,72 1,76 1,80 1.84 Lot size n 3 3 3 4 5 7 10 15 20 25 35 50 up to 50 51 to 90 91 to 150 151 to 280 281 to 500 501 to 1200 1201 to 3200 3201 to 100
32、00 10001 to 35000 35 001 to 150 O00 150001 to500000 500001 and over k 1,12 1,12 1,12 1,17 1,24 1,33 1,41 1.47 1,51 1,53 1,57 1.61 Normal inspection n 4 5 7 10 15 20 25 35 50 75 100 150 k 1,45 1,s 1,62 1,72 1,79 1,82 1,85 1 ,= 1.93 1,98 2,oo 2,03 rightened inspection n 5 5 7 10 15 20 25 35 50 75 100
33、150 k ,65 1,65 1.75 1 ,84 1,91 1,96 1,98 2,03 2.08 2,12 2,14 2,18 Table A.2 - Inspection level 1 - AQL = 1,5 YO Reduced inspection n 4 4 4 4 5 7 10 15 20 25 35 50 k 2,34 134 13 1,34 1,40 1,50 1 ,= 1,65 1,69 1,72 1,76 1 ,80 Lot size Up to 50 51 to 90 91 to 150 151 to 280 281 to 500 501to 1200 1201 to
34、 3 200 3201 to 10000 10 001 to 35 o00 35 001 to 150 000 150001 to500000 500001 and over Normal inspection 3 Copyright International Organization for Standardization Provided by IHS under license with ISONot for ResaleNo reproduction or networking permitted without license from IHS-,-,-IS0 8197 : 19&
35、8 (E) Table A.3 - Inspection level 1 - AQL = 2,5 % Normal inspection I Tightened inspection I Reduced inspection n I k I n I k n Lot size k 0,958 0,958 0,958 0,958 1 ,o1 1 ,O7 1,15 1 ,a 13 1833 1,35 1,39 1,42 3 4 5 7 10 15 20 25 35 50 75 100 150 1,12 1,17 1,24 13 1,41 1,47 1,51 133 1.57 1,61 1,65 1,
36、67 1,70 4 4 5 7 10 15 20 25 35 50 75 100 150 3 3 3 3 4 5 7 10 15 20 25 35 50 Up to 25 26tO 50 51 to 90 91 to 150 151 to 280 281 to 500 501to 1200 1201 to 3200 3 201 to 10 000 10001 to 35000 35 O01 to 150 000 150001 to500000 500001 and over Table A.4 - Inspection level I - AQL = 4 Yo Lot size Normal
37、inspection lightened inspection Reduced insoectlon n k 1,12 1,17 1,24 1 ,33 1,41 1,47 1,51 13 1,57 1,61 1.65 1.67 k k 0,958 1,Ol 1 ,O7 1,15 1,23 1,30 1 ,a 1,35 It39 1,42 I ,46 1.48 n n 3 4 5 7 10 15 20 25 35 50 75 100 3 4 5 7 10 15 20 25 35 50 75 IO0 3 3 3 3 4 5 7 10 15 20 25 35 0,765 0,765 0,765 0,
38、765 0,814 0,874 0,955 1 ,o3 1 ,o9 1,12 1,14 1.18 Up to 25 26to 5 51 to 90 91 to 150 151 to 280 281 to MK) 501to 1200 1201 to 3200 3201 to loo00 10001 to 35000 35 O01 to 150 000 150001 and over Table A.5 - Inspection level 1 - AQL = 6,5 YO Reduced inspection Lot size Normal inspection Tightened inspe
39、ction - n n k k k n Up to 25 26to 50 51 to 90 91 to 160 151 to 280 281 to 500 501to 1200 1201 to 3 200 3 201 to 10 o00 10 O01 to 35 o00 35 001 and over 3. 4 5 7 10 15 20 25 35 50 75 3 4 5 7 10 15 20 25 35 50 75 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 0,917 0,9
40、36 0,958 1,Ol 1 ,O7 1,15 1,23 1.30 13 1,35 13 1,42 1,46 0,765 0,814 0,874 0,955 1 ,o3 1 ,o9 1,12 1,14 1,18 1,21 1,24 4 Copyright International Organization for Standardization Provided by IHS under license with ISONot for ResaleNo reproduction or networking permitted without license from IHS-,-,-IS0
41、 8197 : 1988 (E) n k 3 0,566 4 0,617 5 0,675 7 0,755 10 0,828 15 0,886 20 0,917 25 0,936 35 0,969 50 1 ,o0 Table A.6 - Inspection level 1 - AQL = 10 YO n 3 4 5 7 10 15 20 25 35 50 Lot size k 0,765 0,814 0,874 0,955 1 ,O3 1 .o9 1,12 1,14 1.18 1,21 _ Up to 25 26 to 50 51 to 90 91 to 150 151 to 280 281
42、 to 500 501 to 1200 1201 to 3200 3 201 to 10 o00 10 O01 and over n 3 3 3 3 4 5 7 10 15 20 Normal inspection I Tightened inspection I Reduced inspection k 0,341 0,341 0,341 0,341 0,393 0,455 0,536 0,611 0,664 0,695 Copyright International Organization for Standardization Provided by IHS under license
43、 with ISONot for ResaleNo reproduction or networking permitted without license from IHS-,-,-IS0 8197 : I983 (E) UDC 37.1/.3 : 620.11 Descriptors : agricultural products, dairy products, milk, sampling, inspection by measurements. Price based on 5 pages Copyright International Organization for Standardization Provided by IHS under license with ISONot for ResaleNo reproduction or networking permitted without license from IHS-,-,-
