BS 7274:1990 download.pecification for Wheat.
1 Scope
BS 7274 lays down minimum specifications for wheat (Triticurn aestivum) intended for human consumption and which is the subject of international trade.
It also gives an indicative list of harmful and toxic seeds (Annex A), a list of unacceptable insect pests of stored cereals (Annex B) and a method for the determination of the impurities content (Annex C).
2 Normative references
The following standards contain provisions which, through reference in this text, constitute provisions of BS 7274. At the time of publication, the editions indicated were valid. All standards are subject to revision, and parties to agreements based on BS 7274 are encouraged to investigate the possibility of applying the most recent editions of the standards listed below. Members of IEC and ISO maintain registers of currently valid International Standards.
ISO 712:1985, Cereals and cereal products — Determination of moisture content
(‘Routine reference method,).
ISO 950:1979, Cereals — Sampling as grain). ISO 3093:1982. Cereals — Determination of falling number.
ISO 5223:1983, Test sieves for cereals. Iso 7971:1986, Cereals — Determination of bulk density, called “mass per hectolitre” (Reference method).
3 Definitions
For the purposes of BS 7274, the following definitions apply.
impurities
damaged wheat grains and all organic and inorganic materials other than wheat grains
the impurities comprise four main categories as follows: damaged wheat grains (3.1). other cereals (3.2), extraneous matter (3.3), and harmful andlor toxic seeds, bunted grains and ergot (3.4) (See also Table C.1.)
3.1 Damaged wheat grains
3.1.1
broken grains
grains of wheat in which part of the endosperm is exposed. This includes wheat without germ
3.1.2
shrivelled grains
whole grains, whatever their condition, which pass through a sieve with long rounded apertures 1,70 mm wide
3.1.3 Unsound grains
3.1.3.1
mouldy grains
grains which have moulds visible to the naked eye on 50 % of the surface andlor in the kernel
3.1.3.2
heat-damaged grains
grains which have a chestnut to black coloration resulting from the effect of heat
3.1.4
grains attacked by pests
grains which show visible damage owing to attack by rodents, insects, mites or other pests
3.1.5
sprouted grains
sprouted grains are not taken into account as such, but according to the a-amylase activity which results from their presence and which is expressed as the falling number (see 4.2.4)
3.2
other cereals
cereal grains belonging to species other than Triticum aestivum
3.3
extraneous matter
after removal of ergot, this category includes:
— all the components of the sample, with the exception of grains of other cereals (3.2). grains of wheat, harmful and/or toxic seeds (3.4.1) and bunted grains (3.4.2), which are retained by a sieve with long rounded apertures 3,55 mm wide and all the components which pass through a sieve with long rounded apertures 1,00 mm wide. (By convention, the latter shall be considered to be inorganics.)
— all the organic components other than grains of wheat, other cereals (3.2), harmful and/or toxic seeds (3.4.1), bunted grains (3.4.2), foreign seeds, fragments of straw, dead insects and fragments of insects, etc., and inorganic components such as stone and sand, which pass through a sieve with long rounded apertures 3,55 mm wide and which are retained by a sieve with long rounded apertures 1,00 wide.
3.4 Harmful and/or toxic seeds, bunted grains and ergot
3.4.1
harmful and/or toxic seeds
seeds which if present in quantities above a certain limit may have a damaging or dangerous effect on health, organoleptic properties or technological performance
an indicative list of these seeds is given in Annex A
3.4.2
bunted grains
grains filled with a fetid-smelling dust comprising the spores of the bunts, i.e. Tilletia caries, Tilietia con troversa, Tilletia foetida, Tilietia intermedia, Tilletia triticoides and Neouossia indica
3.4.3
ergot
scierotium of the fungus Claviceps purpurea
4 Requirements
4.1 General organoleptic and health characteristics
Wheat grains shall be sound. clean, have no foreign odours or odours denoting any deterioration, and shall be free of additives and toxic substances.
Pesticide residues and other contaminants shall not exceed the maximum levels laid down in the national legislation of the country of destination or, in the absence of such legislation, the maximum levels laid down by the joint FAO/WHO Codex Alimentarius Commission.
Wheat shall be free from the living insects (visible to the naked eye) listed in Annex B.
4.2 Physical and chemical characteristics
4.2.1 Moisture content
The moisture content of wheat, determined in accordance with ISO 712, shall not be greater than 15,5 %.
NOTE Lower moisture contents are required for certain destinations, in relation to the climate, and duration of transport and of storage. For further information, see ISO 6322-1, ISO 6322-2 and ISO 6322.3.
4.2.2 Bulk density
The bulk density (mass per hectolitre) of wheat shall be determined using instruments calibrated according to the reference method given in ISO 7971, and shall not be less than 70 kg/hl.
4.2.4 a-amylase activity
The a-amylase activity (see 3.1.5) determined in accordance with ISO 3093, and expressed as the falling number, shall be not less than 160.
5 Sampling
Sampling shall be carried out in accordance with
ISO 950.
6 Test methods
The tests shall be carried out using the methods specified in 4.2.