BS 6986-1-1988 Analysis of instant tea - Methods of sampling《速溶茶的分析 第1部分 取样方法》.pdf

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1、BRITISH STANDARD CONFIRMED OCTOBER 1993 BS 6986-1: 1988 ISO 7516:1984 Analysis of instant tea Part 1: Methods of sampling ISO title: Instant tea in solid form Sampling UDC 663.95:620.113BS6986-1:1988 This British Standard, having been prepared under the directionof the Food and Agriculture Standards

2、 Committee,was published underthe authority of the BoardofBSI and comes into effect on 31August1988 BSI 12-1999 The following BSI references relate to the work on this standard: Committee reference FAC/8 Draft (ref. 87/54513) announced inBSI News November1987 ISBN 0 580 16723 2 Committees responsibl

3、e for this British Standard The preparation of this British Standard was entrusted by the Food and Agriculture Standards Committee (FAC/-) to Technical Committee FAC/8, upon which the following bodies were represented: Department of Trade and Industry (Laboratory of the Government Chemist) Ministry

4、of Agriculture, Fisheries and Food Overseas Development Natural Resources Institute Paper Sack Development Association Ltd. Tea Producers Association United Kingdom Tea Association Amendments issued since publication Amd. No. Date of issue CommentsBS6986-1:1988 BSI 12-1999 i Contents Page Committees

5、 responsible Inside front cover National foreword ii 0 Introduction 1 1 Scope and field of application 1 2 Definitions 1 3 General conditions of sampling 2 4 Sampling from immediate containers 2 5 Packaging and labelling of laboratory sample 4 6 Dispatch of laboratory samples 4 7 Sampling report 4 T

6、able 1 2 Table 2 2 Publication referred to Inside back coverBS6986-1:1988 ii BSI 12-1999 National foreword This Part of BS6986 has been prepared under the direction of the Food and Agriculture Standards Committee. It implements an agreement, to which the UK was a party, reached in Subcommittee 8, Te

7、a, of Technical Committee34, Agricultural food products, of the International Organization for Standardization (ISO). The UK also provides the secretariat for the Subcommittee. This Part of BS6986 is identical with ISO7516:1984 “Instant tea in solid form Sampling”. Terminology and conventions. The t

8、ext of the International Standard has been approved as suitable for publication as a British Standard without deviation. Some terminology and certain conventions are not identical with those used in British Standards; attention is drawn especially to the following. Wherever the words “International

9、Standard” appear, referring to this standard, they should be read as “Part of BS6986”. 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 i

10、tself confer immunity from legal obligations. Cross-reference International Standard Corresponding British Standard ISO 3534:1977 BS 5532 Statistical terminology Part 1:1978 Glossary of terms relating to probability and general terms relating to statistics (Identical) Summary of pages This document

11、comprises a front cover, an inside front cover, pages i and ii, pages1 to 4, an inside back cover and a back cover. This standard has been updated (see copyright date) and may have had amendments incorporated. This will be indicated in the amendment table on the inside front cover.BS6986-1:1988 BSI

12、12-1999 1 0 Introduction Being a natural product, instant tea may exhibit variable characteristics associated with the season of manufacture and/or the source of leaf material. In addition, variable manufacturing characteristics, such as bulk density, powder flowability and particle size, are critic

13、ally important. For these reasons, it is desirable that a sample of any lot or consignment is prepared at the factory and forwarded to the customer for approval prior to the instant tea being dispatched from the factory. In order to confirm that a given consignment of instant tea conforms to a contr

14、act specification, a buyer may wish to sample a representative number of boxes on arrival at his premises. However, instant tea in solid form is generally packed and transported in bulk in sealed bags of moisture-resistant material (i.e.an immediate container), protected by an outer container. Owing

15、 to the hygroscopic nature and friability of the product, special precautions need to be taken in order to ensure that the taking of samples does not adversely affect the sample itself or the remainder of the lot. 1 Scope and field of application This International Standard specifies methods of samp

16、ling instant tea in solid form (hereinafter referred to as “instant tea”). It applies to sampling from containers of all sizes. Separate methods are described for sampling at the point of manufacture, sampling at subsequent stages in the distribution chain and sampling of retail packs. In addition,

17、for sampling at some of these locations, different procedures or special precautions are specified depending on whether the samples are to be used for examination of particle characteristics (for example bulk density, flowability, particle size) or compositional characteristics (for example moisture

18、 content, ash). 2 Definitions For the purpose of this International Standard, the following definitions apply. 1) 2.1 consignment the quantity of instant tea dispatched or received at one time and covered by a particular contract or shipping document. The consignment may be made up of one or more lo

19、ts or parts of lots 2.2 lot; break a defined quantity of instant tea, presumed to be of uniform characteristics, taken from a consignment and allowing the quality to be assessed 2.3 primary sample 2) a small quantity of instant tea, taken at one time from one point in a single immediate container, o

20、r, where appropriate, the whole contents of one immediate container in the lot in the case of containers containing less than 1kg of instant tea (see4.3.5) NOTEA series of primary samples is taken from different positions in the lot. 2.4 bulk sample the quantity of instant tea obtained by bringing t

21、ogether the primary samples taken from different positions in the lot and which is representative of the quality of the lot 2.5 laboratory sample a prescribed quantity of instant tea taken from the bulk sample, representative of the quality of the lot and intended for analysis or other examination 2

22、.6 point of manufacture the point in the factory at which the instant tea is being poured into its first immediate container up to the time when the immediate container is sealed 2.7 immediate container the container that is in contact with the instant tea; it may be surrounded by an outer container

23、 or outer containers examples of immediate containers are: a) a sealed bag in which tea is transported in bulk, protected by an outer container such as a fibreboard box; b) a glass jar or sealed bag in a box in which the instant tea is packed usually for retail sale. 2.8 retail pack any package in w

24、hich the immediate container contains less than1kg of instant tea 1) The terms and definitions in this clause take cognizance of, but are not identical with, those in ISO3534, Statistics Vocabulary and symbols 2) In ISO 3534, the term “increment” is used for this concept, but this term is not used i

25、n sampling in the tea trade.BS6986-1:1988 2 BSI 12-1999 3 General conditions of sampling 3.1 Sampling shall be carried out by persons appointed by buyers and/or sellers and, if desired, in the presence of the buyer (or his representatives) and the seller (or his representatives). 3.2 Sampling shall

26、be carried out in a covered place, in such a manner that the samples of instant tea, the sampling apparatus and the sample containers are protected from adventitious contamination and other factors likely to affect the samples, for example moisture, dust, etc. Special care is necessary to ensure tha

27、t the sampling instruments are clean and dry, and do not impart any taint or contamination to the sample. 3.3 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 charact

28、eristics of the instant tea. 3.4 If it is obvious from the visual appearance of the primary samples that the lot is not uniform within the definition of “lot” (see2.2), the sampling shall be discontinued and reference made back to the person who ordered the sampling to be carried out. 4 Sampling fro

29、m immediate containers 4.1 Number of immediate containers to be sampled Unless otherwise specified in4.3 or in a contract, the number of immediate containers to be sampled shall be as given in4.1.1 to4.1.3. 4.1.1 Immediate containers containing more than20kg of instant tea In the case of immediate c

30、ontainers containing more than20kg of loose instant tea, the minimum number of containers to be sampled from a lot shall be as shown inTable 1. Table 1 4.1.2 Immediate containers containing not more than 1 kg of instant tea In the case of immediate containers containing not more than1 kg of loose in

31、stant tea, the minimum number 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 4.1.3 Immediate containers containing 1 to 20 kg of instant tea The minimum number of immediate containers to be sampled

32、from a lot shall be that shown inTable 1 orTable 2, according to agreement between the interested parties. 4.2 Procedure for random sampling The containers to be sampled shall be taken at random, and, for this purpose, use should be made of random number tables. If such tables are not available, the

33、 following procedure may be used: Let N be the number of immediate containers in the lot and n be the number of immediate containers to be taken. Starting from any immediate container, count the immediate containers in order as1,2, etc., up to r, where r = N/n (If N/n is not a whole number, take r a

34、s the integral part of it). Select the rth immediate container, until the required number of immediate containers has been taken. In the case of immediate containers containing not more than1 kg of instant tea, if the containers are packed in outer cases, cartons or crates containing a convenient nu

35、mber of units, approximately20% (but, not fewer than two) of these outer packages shall be taken at random. From these, immediate containers shall be taken in equal numbers, at random, so as to make up the required number of immediate containers to be sampled, as specified in4.1.2. 4.3 Primary sampl

36、es 4.3.1 General The method of taking primary samples depends on the point in the manufacturing and distribution chain at which sampling is to be undertaken and can depend on the methods of analysis that will be made on the samples. When sampling at the point of manufacture, methodA (see4.3.2) shall

37、 be used. The samples so obtained may be used for any determination. Number of immediate containers in lot Number of immediate containers to be sampled 2 to 10 11 to 25 26 to 100 101 and over 2 3 5 7 Number of immediate containers in lot Number of immediate containers to be sampled up to 25 26 to 10

38、0 101 to 300 301 to 500 501 to 1 000 1 001 to 3 000 3 001 and over 3 5 7 10 15 20 25BS6986-1:1988 BSI 12-1999 3 When sampling at any point after the point of manufacture, provided that the instant tea is not packed in retail packages method B (see4.3.3) shall be used when the samples are required fo

39、r determinations of bulk density, flowability and particle size. The samples shall not be used for the determination of moisture content but may be used for any other determinations. method C (see4.3.4) shall be used when the samples are required for the determination of moisture content. The sample

40、s shall not be used for determinations of bulk density, flowability and particle size but may be used for any other determinations. When sampling retail packs, method D (see4.3.5) shall be used. The samples so obtained may be used for any determination. 4.3.2 Method A 4.3.2.1 Apparatus The following

41、 apparatus is required: powder scoop polyethylene bag (large enough to hold all primary samples) 4.3.2.2 Procedure Using the scoop, take a primary sample from each immediate container (in the lot) as it is being filled or when filled but before it is sealed. Place the primary samples in the polyethy

42、lene bag. Minimize the risk of take up or loss of moisture by keeping the polyethylene bag holding the primary samples closed except when inserting further samples, and with as little air inside as possible. Use the primary samples to obtain a bulk sample (see4.4). 4.3.3 Method B 4.3.3.1 Apparatus T

43、he following apparatus is required: polyethylene bags at least equal in volume to those in which the instant tea is received from the manufacturer powder scoop polyethylene bag (large enough to hold all the primary samples) polyethylene heat sealer (optional) 4.3.3.2 Procedure The number of immediat

44、e containers to be sampled from a given lot or consignment shall either be subject to prior agreement between the interested parties, or, in the absence of such agreement, in accordance with4.1. The required number of immediate containers shall be withdrawn from the lot or consignment according to a

45、 system of random numbers. Operating preferably in an air-conditioned room, open completely one of the outer containers and the immediate container inside it. Gently pour at full flow the entire contents of the immediate container into a polyethylene bag so that the contents are mixed and any layers

46、 destroyed. Using the scoop, take a primary sample from the top surface of this bag and place it in another polyethylene bag (i.e.the bag which will contain the bulk sample). Place the filled bag in its outer container and seal it using the heat sealer or other effective method of sealing. Repeat th

47、e procedure on all the other immediate containers to be sampled. Use the primary samples to obtain a bulk sample (see4.4). 4.3.4 Method C 4.3.4.1 Apparatus The following apparatus is required: a suitable trier polyethylene bag (large enough to hold all the primary samples) polyethylene heat sealer (

48、optional) 4.3.4.2 Procedure The number of immediate containers to be sampled from a given lot or consignment shall either be subject to prior agreement between the interested parties, or, in the absence of such agreement, in accordance with4.1. The required number of immediate containers shall be wi

49、thdrawn from the lot or consignment according to a system of random numbers. Open each outer container and its immediate container, causing as little damage as possible. Using the trier, take a primary sample from the immediate container and place it in the polyethylene bag. Reseal the immediate container using the heat sealer or other effective method of sealing and reseal the outer container. Minimize the risk of take up or loss of moisture by keeping the polyethylene bag holding the primary samples closed except when inserting further samples, a