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1、International Standard INTERNATIONAL ORGANIZATION FOR STANDARDIZATION.MEX,!IYHAPOHAR OPl-AHM3AWR l-l0 CTAHAPT3ALWlRGANISATION INTERNATIONALE DE NORMALISATION Tea - Sampling Thk - khan tillonnage First edition - 1980-02-15 UDC 663.95 : 543.053 : 620.113 Descriptors : agricultural products, tea, packa
2、ges, sampling. Ref. No. OS0 18394980 (E) Price based on 3 pages Foreword IS0 (the International Organization for Standardization) is a worldwide federation of national standards institutes (IS0 member bodies). The work of developing Inter- national Standards is carried out through IS0 technical comm
3、ittees. Every member body interested in a subject for which a technical committee has been set up has the right to be represented on that committee. International organizations, governmental and non-governmental, in liaison with ISO, also take part in the work. Draft International Standards adopted
4、by the technical committees are circulated to the member bodies for approval before their acceptance as International Standards by the IS0 Council. International Standard IS0 1839 was developed by Technical Committee lSO/TC 34, Agricultural foodproducts. It is the result of the combination into one
5、single document of the revision of International Standards IS0 1839/l-1975 and 1839/2-1976 and draft International Standard ISO/DIS 1839/3, which was submitted to member bodies in February 1977, and which was approved by the member bodies of the following coun- tries : Austria Canada Chile Egypt, Ar
6、ab Rep. of France Ghana Hungary India Romania Iran South Africa, Rep. of Israel Thailand Korea, Rep. of Turkey Mexico United Kingdom New Zealand USA Poland Yugoslavia The member bodies o f the following countries expr national Standard on technical grou nds : disapproval of the draft Inter- Australi
7、a Ireland International Standard IS0 1839/l-1975 had been approved by the member bodies of the following countries : Australia Brazil Chile Czechoslovakia Egypt, Arab Rep. of France Germany, F. R. Greece Hungary India Iran Israel Korea, Rep. of Netherlands New Zealand Peru Poland Portugal Romania So
8、uth Africa, Rep. of Sri Lanka Thailand Turkey United Kingdom International Standard IS0 1839/2-1976 had been approved by the member bodies of the following countries : Austria Belgium Brazil Bulgaria Canada Chile Czechoslovakia Egypt, Arab Rep. of France Germany, F. R. Hungary India Iran Israel Mexi
9、co Netherlands New Zealand Poland Portugal Romania South Africa, Rep. of Turkey United Kingdom USA Yugoslavia No member body had expressed disapproval of these International Standards. This first edition cancels and replaces International Standards IS0 1839/l-1975 and IS0 183912-1976. International
10、Organization for Standardization, 1980 Printed in Switzerland -,-,- INTERNATIONAL STANDARD IS0 1839-1980 (E) Tea - Sampling 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. 3 Apparatus 3.1 Spo
11、ons, scoops, borers or other instruments, suitable for taking samples from the interior of containers. 3.2 Dividing apparatus, suitable for the purpose of redu- cing the bulk sample to obtain the laboratory samples. 2 Definitions For the purpose of this International Standard the following definitio
12、ns apply. 1) 4 General 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 defined quantity of tea, intended to be uniform. 2.3 pr
13、imary sample2) : A small quantity of tea, taken at one time from one point in a single container, or, where appro- priate, the whole contents of one container in the lot (in the case of containers containing less than 1 kg of tea) (see 5.3). NOTE - A series of primary samples is taken from different
14、 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 (see 5.4). 2.5 laboratory sample : A prescribed quantity of tea taken from the bulk sample, r
15、epresentative of the quality of the lot and intended for analysis or other examination (see 5.5). 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
16、shall be carried out in a covered place, in such a manner that the samples of tea, the sampling instruments and the sample containers are protected from adventitious contami- nation and other factors likely to affect the samples, for exam- ple moisture, dust, radiation, etc. Special care is necessar
17、y to ensure that the sampling instru- ments 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
18、 characteristics of the tea. 4.4 If examination of primary samples shows that the lot is not uniform within the definition of “lot” (2.21, the sampling shall be discontinued and reference made back to the person who ordered the sampling to be carried out. 1) The terms and definitions in this clause
19、take cognizance of, but are not identical with, those in IS0 3534, Statistics - Vocabulary and symbols. 2) In IS0 3534 the term “increment” is used for this concept, but this term is not used in sampling in the tea trade. IS0 18394980 (E) 5 Sampling from containers 5.1 Number of containers to be sam
20、pled 5.1.1 Containers containing more than 20 kg of loose teal) (for example, tea chests) In the case of containers containing more than 20 kg of loose tea, the minimum number of containers to be sampled from a lot shall be as shown in table 1. Table 1 Number of containers Number of containers in lo
21、t to be sampled 2to 10 2 11 to 25 3 26 to 100 5 101 and over 7 5.1.2 Containers containing not more than 1 kg of loose tea In the case of containers containing not more than 1 kg of loose tea, the minimum number (see 5.3) of containers to be sampled from a lot shall be as shown in table 2, provided
22、that the mass specified for each laboratory sample is obtained. Table 2 Number of containers 1 / “uyo”;,cmo;y 1 up to 25 I 3 26 to 100 5 101 to 300 7 301 to 500 10 501 to 1000 15 1001t03000 20 3 001 and over 25 5.1.3 Containers containing 1 to 20 kg of loose tea The minimum number of containers to b
23、e sampled from a lot shall be that shown in table 1 or table 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 this purpose, use should be made of random number tables. If such tables are not ava
24、ilable, the following procedure may be used : Let IV be the number of containers in the lot and n the number of containers to be taken. Starting from any con- tainer, count the containers in order as 1, 2, . . . . etc. up to r, where r = N/n. (If N/n is not a whole number, take r as the integral par
25、t of it). Select the rth container as a sample. Continue counting and selecting every rfh container, until the required number of containers has been taken. In the case of containers containing less than 1 kg of loose tea, if the containers are packed in outer cases, cartons or crates containing a c
26、onvenient number of units, approx- imately 20 % (but, not fewer than two) of the outer packages shall be taken at random. From these, small con- tainers shall be taken in equal numbers, at random, so as to make up the required number of containers to be sampled, as specified in 5.1.2. 5.3 Primary sa
27、mples 5.3.1 Containers containing more than 20 kg of loose tea In the case of containers containing more than 20 kg of loose tea, take, by means of the apparatus mentioned in 3.1, a primary sample of 50 g, representative of the contents, from each container taken from the lot as described in 5.2. NO
28、TE - In most cases it would be impracticable and purposeless to re-blend the contents of a large container of tea with a view to obtain- ing a fully representative sample, and a sample taken in the ordinary way, by boring or after opening the container, is sufficiently represen- tative. In special c
29、ases, 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 5.3.2.1 If the amount of tea in each container ta
30、ken from the lot as described in 5.2 does not exceed 50 g, each of the con- tainers shall constitute a primary sample. 5.3.2.2 If the amount of tea in each container exceeds 50 g, it shall be carefully mixed and a primary sample of 50 g shall then be taken by means of the apparatus mentioned in 3.1.
31、 5.3.2.3 If the amount of tea in each container is less than 100 g, select a sufficient number of containers to obtain the minimum mass for each laboratory sample as specified in 5.5. 5.3.3 Containers containing ? to 20 kg of loose tea if appropriate, i.e. particularly in the case of smaller contain
32、ers within the range 1 to 20 kg, the contents of the container shall be well mixed. Then, by means of the apparatus mentioned in 3.1, a primary sample of 50 g, representative of the contents, shall be taken from each container selected, as described in 5.3.2.2. Otherwise proceed as described in 5.3.
33、1. 1) “Loose tea” means tea in containers not otherwise packeted. 2 -,-,- is0 1839-1980 E) 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, com- bine them to constitute the bulk sample (see 5.5.1). 5.43 If th
34、e primary samples consist of intact pre-packed units, the whole shall form the bulk sample and shall be for- warded 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
35、 and then divid- ed down to the required number of laboratory samples. NOTE - Replicate 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 recogni
36、zed trade practices, unless otherwise agreed. 5.52 If the bulk sample consists of unopened single con- tainers, 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 than 100 g for t
37、he purposes of chemical analysis and not less than 50 g for sensory tests, unless 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
38、almost completely filled by the sample. It is imperative that containers for samples for sensory tests are seasonedl) 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
39、, fitted with air- tight and moisture-tight closures. The containers shall be com- pletely filled and the closures shall be sealed to prevent loosen- ing or tampering. NOTE - Owing to the hygroscopic character of tea, it is essential to transfer the samples to their containers as promptly as possibl
40、e. 6.2 Labelling of samples Each sample container shall carry a label marked with full 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 t
41、he specie (grade). 7 Despatch of samples Samples shall be despatched as soon as possible and only in exceptional circumstances more than 48 h 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
42、made to any unusual appearance of the container, and all the circumstances that may have 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
43、 witnesses; sampling personnel and e) identification of the method tions to the technique described; used, and any modifica- 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
44、number, etc.); h) destination of samples; j) condition of packages and surroundings; k) if required, atmospheric conditions during sampling, including relative humidity. -. 1) Seasoning of sample containers sample before use to eliminate taint involves exposure of the inside to the atmosphere (“air -ing off”) or storage with tea of the whether from the container itsel f or from tea previously contained irl it. same type as tk 3 -,-,- This page intentionally left blank -,-,- This page intentionally left blank This page intentionally left blank