1 Scope
This standard specifies methods of sampling animal feeding stuffs, including fish feed, for quality control for commercial, technical and legal purposes.
It is not applicable to pet foods. Nor are the methods intended for sampling for the purpose of microbiological examination. Sampling methods are specified separately for determining the physical characteristics of feeding stuffs under certain conditions.
For certain categories of animal feeding stuffs, specific methods of sampling are specified in other international standards. A list of these can be found in the bibliography. Methods of sampling for the determination of substances likely to be non-uniformly distributed are described in Annex A.
2 Terms and definitions
For the purpose of this standard, the following terms and definitions apply.
2.1
consignment
a specified quantity of feeding stuff on offer, dispatched or received at one time
Note: It may consist of one or more lots (see 2.2).
2.2
lot
an identified quantity of a consignment having characteristics presumed to be uniform
2.3
increment
a quantity of material taken at one time from a single point in a lot
2.4
bulk sample
sample obtained by combining and mixing all the increments taken from the same lot
Note: A collection of distinct and identifiable increments intended for separate investigation may be denoted the “gross sample”.
2.5
reduced sample
a representative part of the bulk sample, obtained by a process of successive division or reduction in such a manner that the mass or volume approximates to that of the laboratory samples
2.6
laboratory sample
a sample representative of the quality and condition of the lot, obtained by division of the reduced sample and intended for analysis or other examination
Note: For each sample taken, three or four laboratory samples are normally produced. One of these should be submitted for testing and at least one stored for reference purposes. If more than four laboratory samples are required, the quantity of the reduced sample will have to be increased so that the minimum quantity requirement for all laboratory samples can be met.
3 General principles
3.1 Representative sampling
The purpose of representative sampling is to obtain a small fraction from a lot in such a way that a determination of any particular characteristic of this fraction will represent the mean value of the characteristic of the lot.
3.2 Selective sampling
If portions of a lot to be sampled show a noticeable difference in quality from the rest, such portions shall be separated from the lot and treated as a separate lot for sampling. In such cases, mention shall be made of this fact in the sampling report.
3.3 Statistical considerations
Acceptance sampling is the usual method of sampling for animal feeding stuffs. For sampling by attributes, there is a theoretical sampling plan based on a binomial distribution, but, for practical purposes, this plan has been simplified to a square-root relationship between the lot size and the number of increments.
Note 1: With bulk products, sample variances can be expected to be acceptably uniform if, for lots up to 2.5 t, at least seven increments are taken and, for lots between 2.5 t and 80 t, the number of increments taken is at least equal to , where m is the mass, in t, of the lot. If the lot exceeds 80 t, the square-root relationship is still applicable, but the risk of making incorrect decisions on the basis of the samples increases. However, this can be the subject of agreement between the interested parties.
Note 2: The application of the square-root relationship is somewhat different for the sampling of packaged animal feeding stuffs, for liquids and semi-liquids, for blocks and licks and for roughages, because the sample size may vary.
Foreword i
1 Scope
2 Terms and definitions
3 General principles
4 Sampling personnel
5 Identification and general inspection of the product prior to sampling
6 Sampling equipment
7 Sample containers
8 Sampling procedure
9 Packing, sealing and marking of samples and sample containers
10 Sampling report
Annex A (informative) Sampling of feeding stuffs containing undesirable substances which are likely to be non-uniformly distributed, including mycotoxins, castor-oil seed husks and poisonous seeds
Bibliography
