BS 5987-1980 Methods for sampling tea《茶的取样方法》.pdf

1、BRITISH STANDARD CONFIRMED OCTOBER 1995 BS 5987:1980 ISO 1839:1980 Methods for Sampling tea UDC 663.95:620.113BS5987:1980 This British Standard, having been prepared under the directionof the Food and Agriculture Standards Committee,was published underthe authority of the Executive Board and comes i

2、ntoeffect on 29August1980 BSI 12-1999 The following BSI references relate to the work on this standard: Committee reference FAC/8 Draft for comment 77/51686 DC ISBN 0 580 11597 6 Cooperating organizations The Food and Agriculture Standards Committee, under whose direction this British Standard was p

3、repared, consists of representatives from the following: Agricultural Co-operation and Marketing Services Agricultural Research Council, Meat Research Institute British Food Manufacturing Industries Research Association British Industrial Biological Research Association Ltd. Campden Food Preservatio

4、n Research Association Consumer Standards Advisory Committee of BSI Department of Agriculture and Fisheries for Scotland Department of Agriculture (Government of Northern Ireland) Department of Industry (Laboratory of the Government Chemist)* Flour Milling and Baking Research Association Food and Dr

5、ink Industries Council Food Manufacturers Federation Incorporated Institute of Brewing Local Authorities Co-ordinating Body of Trading Standards Ministry of Agriculture, Fisheries and Food* National Farmers Union National Farmers Union of Scotland Tobacco Advisory Council The organizations marked wi

6、th an asterisk in the above list, together with the following, were directly represented on the Technical Committee entrusted with the preparation of this British Standard: British Tea Producers Association Overseas Development Administration Tropical Products Institute Tea Trade Committee Amendment

7、s issued since publication Amd. No. Date of issue CommentsBS5987:1980 BSI 12-1999 i Contents Page Cooperating organizations Inside front cover National foreword ii 1 Scope and field of application 1 2 Definitions 1 3 Apparatus 1 4 General 1 5 Sampling from containers 1 6 Packaging and labelling of s

8、amples 3 7 Despatch of samples 3 8 Sampling report 3 Table 1 2 Table 2 2 Publication referred to Inside back coverBS5987:1980 ii BSI 12-1999 National foreword This British Standard embodies an agreement, in which the UK has taken part, reached in Sub-committee8, Tea, of the Technical Committee34, Ag

9、ricultural food products, of the International Organization for Standardization (ISO). The UK also provides the Secretariat for the Sub-committee. This standard is identical with ISO1839 “Sampling Tea” published in1980. Terminology and conventions. The text of the International Standard has been app

10、roved as suitable for publication, without deviation, as a British Standard. Some terminology and certain conventions are not identical with those used in British Standards. Where the words “International Standard” appear, referring to this standard, they should be read as “British Standard”. A Brit

11、ish 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-reference International Standard Correspo

12、nding British Standard ISO 3534:1977 BS 5532:1978 Statistics Vocabulary and symbols (Identical) Summary of pages This document comprises a front cover, an inside front cover, pagesiandii, pages1to4, an inside back cover and a back cover. This standard has been updated (see copyright date) and may ha

13、ve had amendments incorporated. This will be indicated in the amendment table on the inside front cover.BS5987:1980 BSI 12-1999 1 1 Scope and field of application This International Standard specifies methods for the sampling of tea. It applies to sampling from containers of all sizes. 2 Definitions

14、 For the purpose of this International Standard the following definitions apply. 1) 2.1 consignment the quantity of goods despatched or received at one time and covered by a particular contract or shipping document. The consignment may be made up of one or more lots or parts of lots 2.2 lot; break a

15、 defined quantity of tea, intended to be uniform 2.3 primary sample 2) a small quantity of tea, taken at one time from one point in a single container, or, where appropriate, the whole contents of one container in the lot (in the case of containers containing less than1kg of tea) (see5.3) NOTEA seri

16、es of primary samples is taken from different positions in the lot. 2.4 bulk sample the quantity of tea obtained by bringing together the primary samples taken from different positions in the lot and which is representative of the quality of the lot (see5.4) 2.5 laboratory sample a prescribed quanti

17、ty of tea taken from the bulk sample, representative of the quality of the lot and intended for analysis or other examination (see 5.5) 3 Apparatus 3.1 Spoons, scoops, borers or other instruments, suitable for taking samples from the interior of containers. 3.2 Dividing apparatus, suitable for the p

18、urpose of reducing the bulk sample to obtain the laboratory samples. 4 General 4.1 Sampling shall be carried out by persons appointed by buyers and sellers and, if desired, in the presence of the buyer (or his representatives) and the seller (or his representatives). 4.2 Sampling shall be carried ou

19、t in a covered place, in such a manner that the samples of tea, the sampling instruments and the sample containers are protected from adventitious contamination and other factors likely to affect the samples, for example moisture, dust, radiation, etc. Special care is necessary to ensure that the sa

20、mpling instruments are clean and dry, and do not impart any foreign odour to the sample. 4.3 Handling of the sample (for example combining of primary samples into the bulk sample, packaging of the sample) shall be carried out with care in order to avoid changing the original characteristics of the t

21、ea. 4.4 If examination of primary samples shows that the lot is not uniform within the definition of “lot”(2.2), the sampling shall be discontinued and reference made back to the person who ordered the sampling to be carried out. 5 Sampling from containers 5.1 Number of containers to be sampled 5.1.

22、1 Containers containing more than 20 kg of loose tea 3)(for example, tea chests) In the case of containers containing more than20kg of loose tea, the minimum number of containers to be sampled from a lot shall be as shown inTable 1. 1) The terms and definitions in this clause take cognizance of, but

23、 are not identical with, those in ISO3534, Statistics Vocabulary and symbols. 2) In ISO3534 the term “increment” is used for this concept, but this term is not used in sampling in the tea trade. 3) “Loose tea” means tea in containers not otherwise packeted.BS5987:1980 2 BSI 12-1999 Table 1 5.1.2 Con

24、tainers containing not more than 1 kg of loose tea In the case of containers containing not more than1kg of loose tea, the minimum number (see5.3) of containers to be sampled from a lot shall be as shown inTable 2, provided that the mass specified for each laboratory sample is obtained. Table 2 5.1.

25、3 Containers containing 1 to 20 kg of loose tea The minimum number of containers to be sampled from a lot shall be that shown inTable 1 orTable 2 according to agreement between the interested parties. 5.2 Procedure for random sampling The containers to be sampled shall be taken at random, and, for t

26、his purpose, use should be made of random number tables. If such tables are not available, the following procedure may be used: Let N be the number of containers in the lot and n the number of containers to be taken. Starting from any container, count the containers in order as1, 2,., etc. up to r,

27、where r = N/n. (If N/n is not a whole number, take r as the integral part of it). Select the r thcontainer as a sample. Continue counting and selecting every r thcontainer, until the required number of containers has been taken. In the case of containers containing less than1kg of loose tea, if the

28、containers are packed in outer cases, cartons or crates containing a convenient number of units, approximately20% (but, not fewer than two) of the outer packages shall be taken at random. From these, small containers shall be taken in equal numbers, at random, so as to make up the required number of

29、 containers to be sampled, as specified in5.1.2. 5.3 Primary samples 5.3.1 Containers containing more than 20 kg of loose tea In the case of containers containing more than20kg of loose tea, take, by means of the apparatus mentioned in3.1, a primary sample of50g, representative of the contents, from

30、 each container taken from the lot as described in5.2. NOTEIn most cases it would be impracticable and purposeless to re-blend the contents of a large container of tea with a view to obtaining a fully representative sample, and a sample taken in the ordinary way, by boring or after opening the conta

31、iner, is sufficiently representative. In special cases, however, for example if tea dust or other adventitious powder is present as an impurity, exceptional measures may be required, especially when the tea is sampled for chemical analysis. 5.3.2 Containers containing not more than 1 kg of loose tea

32、 5.3.2.1 If the amount of tea in each container taken from the lot as described in5.2 does not exceed50g, each of the containers shall constitute a primary sample. 5.3.2.2 If the amount of tea in each container exceeds50g, it shall be carefully mixed and a primary sample of50g shall then be taken by

33、 means of the apparatus mentioned in3.1. 5.3.2.3 If the amount of tea in each container is less than 100g, select a sufficient number of containers to obtain the minimum mass for each laboratory sample as specified in5.5. 5.3.3 Containers containing 1 to 20 kg of loose tea If appropriate, i.e. parti

34、cularly in the case of smaller containers within the range1to20kg, the contents of the container shall be well mixed. Then, by means of the apparatus mentioned in3.1, a primary sample of50g, representative of the contents, shall be taken from each container selected, as described in5.3.2.2. Otherwis

35、e proceed as described in5.3.1. Number of containers inlot Number of containers to be sampled 2 to10 2 11 to25 3 26 to 100 5 101 and over 7 Number of containers inlot Number of containers to be sampled up to 25 3 26 to100 5 101 to300 7 301 to500 10 501 to 1 000 15 1 001 to 3 000 20 3 001 and over 25

36、BS5987:1980 BSI 12-1999 3 5.4 Bulk sample 5.4.1 Form the bulk sample by bringing together the primary samples. 5.4.2 If the primary samples consist of loose material, combine them to constitute the bulk sample (see5.5.1). 5.4.3 If the primary samples consist of intact pre-packed units, the whole sha

37、ll form the bulk sample and shall be forwarded for examination unless a different procedure is agreed. 5.5 Laboratory samples 5.5.1 If the bulk sample is formed by combining primary samples of loose material, it shall be well mixed and then divided down to the required number of laboratory samples.

38、NOTEReplicate samples will be often required, for example as duplicate or reference samples, and in general the number and size of the laboratory samples to be taken for examination and arbitration shall conform to the recognized trade practices, unless otherwise agreed. 5.5.2 If the bulk sample con

39、sists of unopened single containers, the latter shall be used as laboratory samples unless the contracting parties agree on an alternative procedure. 5.5.3 The size of each laboratory sample shall be not less than100g for the purposes of chemical analysis and not less than50g for sensory tests, unle

40、ss otherwise agreed. 6 Packaging and labelling of samples 6.1 Packaging of samples Samples shall be packed in clean, dry, odour-free aluminium or tin-plate containers with close-fitting lids, of such a size that they are almost completely filled by the sample. It is imperative that containers for sa

41、mples for sensory tests are seasoned 4)to avoid taint. The samples shall be protected from light during storage. Samples for the determination of moisture content shall be packed in air-tight and moisture-tight containers, fitted with air-tight and moisture-tight closures. The containers shall be co

42、mpletely filled and the closures shall be sealed to prevent loosening or tampering. NOTEOwing to the hygroscopic character of tea, it is essential to transfer the samples to their containers as promptly as possible. 6.2 Labelling of samples Each sample container shall carry a label marked with full

43、details of the place and date of sampling, the name of the estate or of the blend, the invoice and lot number, the name of the sampler and any other important particulars relating to the consignment, for example the specie (grade). 7 Despatch of samples Samples shall be despatched as soon as possibl

44、e and only in exceptional circumstances more than48h after sampling has been completed, non-business days excluded. 8 Sampling report If a sampling report is prepared, it is recommended that reference should be made to any unusual appearance of the container, and all the circumstances that may have

45、influenced the sampling. It shall include the following details: a) place of sampling; b) date of sampling; c) time of sampling, and time of subsequent sealing of sample containers; d) names and descriptions of sampling personnel and witnesses; e) identification of the method used, and any modificat

46、ions to the technique described; f) nature and number of units constituting the lot, and reference to relevant documents and details of marking; g) number of samples and their identification (markings, batch number, etc.); h) destination of samples; j) condition of packages and surroundings; k) if r

47、equired, atmospheric conditions during sampling, including relative humidity. 4) Seasoning of sample containers involves exposure of the inside to the atmosphere (“airing off”) or storage with tea of the same type as the sample before use to eliminate taint whether from the container itself or from

48、tea previously contained in it.4 blankBS5987:1980 BSI 12-1999 Publication referred to See national foreword.BS 5987:1980 ISO 1839:1980 BSI 389 Chiswick High Road London W4 4AL BSIBritishStandardsInstitution BSI is the independent national body responsible for preparing BritishStandards. It presents

49、the UK view on standards in Europe and at the international level. It is incorporated by Royal Charter. Revisions BritishStandards are updated by amendment or revision. Users of BritishStandards should make sure that they possess the latest amendments or editions. It is the constant aim of BSI to improve the quality of our products and services. We would be grateful if anyone finding an inaccuracy or ambiguity while using this BritishStandard would inform the Secretary of the technical committee responsible, the identity of which can be found on the inside front cove