ISO 4874:2020

ISO 4874:2020 pdf free.Tobacco一Sampling of batches of raw material一General principles.
4 Contractual arrangements
The contract between the interested parties shall state: .
a) at what stages of production and delivery sampling shall be carried out;
b) the party or parties responsible for carrying out the sampling and under whose control;
c) the characteristics to be determined;
d) the laboratory or laboratories that will perform the analyses;
e) the maximum interval of time admissible between sampling and analysis. [This interval should be
as short as possible.)
5 Sampling
5.1 General It is important that the laboratory receive a representative sample which has not been damaged or changed during transport or storage. If it is necessary to sample tobacco taken from cigarettes, the procedures listed in ISO 8243:2013, 4.1.3  should be used.
5.2 Sampling equipment The equipment that is used for sampling the tobacco shall be appropriate for the determination of the characteristics that are specified in Clause 4 c). If physical characteristics such as leaf dimensions or particle size distribution are to be determined, then the sampling equipment shall not alter these characteristics. The sampling equipment shall be clean and dry, and shall not affect any subsequent determination.
5.3 Containers for samples and storage precautions The containers used for collecting the samples shall be made of a chemically inert material. They shall be airtight and preferably opaque.
The samples shall be kept in a dry and cool place protected against light, and in an odour-free
environment to prevent contamination, microbial growth, infestation or other situations which would
affect organoleptic properties.
6 Procedure
6.1 General
The procedure shall include the following steps:
a) labelling of samples for proper identification;
b) selection of sampling units;
c) extraction of increments and constitution of single samples;
d) constitution of the gross sample;
e) constitution of reduced samples;
f) preparation of the laboratory sample(s).
If heterogeneity is of interest as well as mean values, analyses of several laboratory samples is necessary. In these circumstances, the laboratory samples is usually taken from a single sample or a gross sample comprising not more than two or three single samples.
6.2 Treatment of damaged sampling units
The treatment of damaged sampling units depends on the aim of the analyses.
a) If the damage to the tobacco is irrelevant with respect to the characteristics to be determined (for example, disease markings when assessing the length of the leaf), sample damaged units in the same way as undamaged units.
b) If the assessment may be affected by the damage, the damaged sampling units shall be sampled separately and a record made.
c) If the damage to the tobacco is such that the tobacco is unusable for the assessment of the characteristics to be determined, do not sample that sampling unit.
It can be necessary to grade the damage to the tobacco in the damaged sampling units into several classes and obtain sufficient increments from the damaged sampling units.
6.3 Selection of sampling units
6.3.1 General
The selection of sampling units may be carried out by random sampling or by periodic systematic sampling.
The choice of the method to be employed depends on the nature of the consignment. If the batches in the consignment are not identified, random selection of the sampling units is recommended. If the batches in the consignment are marked with successive numbers indicating a production order, then periodic sampling to select sampling units may be suitable.
6.3.2 Selecting the sampling units at random
Draw the sampling units at random from the consignment in such a manner that each unit has the same probability of being selected. Repeat this process until the required number (n) of sampling units has been drawn.ISO 4874 pdf download.

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