ISO 6639-2:2025

International
Standard
ISO 6639-2
Second edition
Cereals and pulses —
2025-06
Determination of hidden insect
infestation —
Part 2:
Sampling
Céréales et légumineuses — Détermination de l'infestation
cachée par les insectes —
Partie 2: Échantillonnage
Reference number
© ISO 2025
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ii
Contents Page
Foreword .iv
1 Scope . 1
2 Normative references . 1
3 Terms and definitions . 1
4 General principles . 2
5 Equipment and devices . 2
6 Sampling location, time and period . 3
6.1 Sampling location and time .3
6.2 Sampling period .3
7 Pre-sampling inspection and identification of lots . 3
8 Sampling of bulk grain . . 4
8.1 Sampling of flowing bulk grain .4
8.2 Sampling of static bulks .4
8.2.1 General .4
8.2.2 Surface sampling .5
8.2.3 Shallow depth sampling .5
9 Sampling of grain in bags . 5
9.1 Sampling bags selection .5
9.2 Increments sampling from bags .6
10 Preparation of laboratory samples . 6
11 Packaging and labelling of laboratory samples . 6
11.1 Packaging .6
11.2 Labelling .6
12 Delivery of laboratory samples . 6
13 Sampling and inspection reports . 6
Bibliography . 7

iii
Foreword
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in the ISO/IEC Directives, Part 1. In particular, the different approval criteria needed for the different types
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This document was prepared by Technical Committee ISO/TC 34, Food products, Subcommittee SC 4, Cereals
and pulses.
This second edition cancels and replaces the first edition (ISO 6639-2:1986), which has been technically
revised.
The main changes are as follows:
— the normative references have been updated;
— the sampling location, time and period have been updated.
A list of all parts in the ISO 6639 series can be found on the ISO website.
Any feedback or questions on this document should be directed to the user’s national standards body. A
complete listing of these bodies can be found at www.iso.org/members.html.

iv
International Standard ISO 6639-2:2025(en)
Cereals and pulses — Determination of hidden insect
infestation —
Part 2:
Sampling
1 Scope
This document specifies methods of sampling cereals and pulses, in bags or in bulk, for the determination of
hidden insect infestation.
This document is applicable to grain in any form of storage structure or transit vehicle at any level of trade
from producer to consumer.
2 Normative references
The following documents are referred to in the text in such a way that some or all of their content constitutes
requirements of this document. For dated references, only the edition cited applies. For undated references,
the latest edition of the referenced document (including any amendments) applies.
ISO 24333:2009, Cereals and cereal products — Sampling
3 Terms and definitions
For the purposes of this document, the following terms and definitions apply.
ISO and IEC maintain terminology databases for use in standardization at the following addresses:
— ISO Online browsing platform: available at https:// www .iso .org/ obp
— IEC Electropedia: available at https:// www .electropedia .org/
3.1
lot
identified quantity of a consignment, to be sampled using a particular sampling plan
Note 1 to entry: Consignment is the physical quantity of grain on offer, dispatched or received at one time, and
covered by a particular contract or shipping document. A consignment may be composed of one or more lots. (See
ISO 5527:2015, 2.1.6.)
Note 2 to entry: There is no need to restrict the size of the lot when sampling for hidden insect infestation. A
consignment of the same origin and history may be regarded as one lot or may be split into several lots for sampling,
whichever is the more convenient. If the consignment is received in several barges, railway wagons, lorries, stacks,
etc., it is usually more convenient to treat each part as a separate lot for sampling purposes. Any parts of a consignment
known to be of different origin and/or history are sampled as separate lots.
Note 3 to entry: The definition of “lot” for the purposes of sampling for determination of hidden insect infestation
differs from the definition of “lot” in International Standards (e.g. ISO 5527:2015, 2.4.1.9, ISO 24333:2009, 2.1) relating
to sampling of grain and pulses for the determination of other characteristics.

3.2
increment
amount of material taken at one time at each individual sampling point throughout a lot (3.1)
[SOURCE: ISO 5527:2015, 2.6.1.10]
3.3
aggregate sample
aggregation of two or more increments (3.2), taken by experimental sampling throughout a lot (3.1),
combined and homogenized
[SOURCE: ISO 24333:2009, 2.4, modified — Admitted term “composite sample” deleted.]
3.4
laboratory sample
sample prepared by homogenizing and dividing an aggregate sample (3.3), or an increment (3.2), for sending
to the laboratory and intended for inspection or testing
[SOURCE: ISO 24333:2009, 2.5, modified “or an increment” added to the definition.]
4 General principles
4.1 Usually there is little or no prior information on the size or distribution of any insect population that
can be present in a lot to be sampled. In these circumstances, it is not possible to adopt a sampling scheme
which is soundly based on statistical theory.
Therefore, the sampling schemes described in this document do not necessarily precisely measure the insect
populations, but have been designed to provide a maximum amount of information in a practical manner.
4.2 Precautions shall be taken to ensure that all sampling equipment and devices are clean and dry before,
during and after the sampling of each lot. Sampling shall be carried out in such a manner as to prevent
insects from elsewhere from entering the samples, sampling apparatus and sample containers.
4.3 Laboratory samples shall be enclosed in sample bags (5.5) and shall be protected from extremes of
temperature and relative humidity and from direct exposure to sunlight. Airtight containers shall not be
used for samples as these may cause any insects present to be asphyxiated. Samples should be analysed
within 24 h of sampling. If immediate analysis is not possible, and there is no requirement to determine the
death or life status of insects, the samples should be frozen before testing.
4.4 If related information about the grain, such as moisture content, is required, separate samples
should be taken in accordance with ISO 24333:2009 or other relevant standards, and should be packaged
accordingly.
5 Equipment and devices
There are many different types of sampling equipment or devices. The most suitable equipment should be
chosen taking into account the product to be sampled, the quantity required and the containers to be used.
Equipment and devices described in this document are not exhaustive.
5.1 Device for sampling from flowing grain, which extracts samples continuously from the entire cross-
section of the grain flow, giving samples of all particle sizes from the lot.
This can be a sophisticated electrically operated automatic sampler including cross-cut sampling devices,
full-flow diverter-type sampling devices, rotating cup sampling devices and bucket elevator sampling
devices (see ISO 24333:2009, Annex A) or a simple pelican scoop operated
...