1、BRITISH STANDARD BS 4317-18: 1988 Methods of test for Cereals and pulses Part 18: Determination of hidden insect infestation UDC 633.1/.3:664.7:636.087.69:620.193.87:620.168.2BS 4317-18:1988 This British Standard, having been prepared under the directionof the Food and Agriculture Standards Committe
2、e, was published under the authority of the Board of BSI and comes intoeffect on 30 December1988 BSI 09-1999 The following BSI references relate to the work on this standard: Committee reference FAC/4 Drafts for comment 85/50928 DC 85/50929 DC 85/50930 DC ISBN 0 580 16942 1 Committees responsible fo
3、r this British Standard The preparation of this British Standard was entrusted by the Food and Agriculture Standards Committee (FAC/-) to Technical Committee FAC/4 upon which the following bodies were represented: AFRC Institute of Engineering Research Agricultural Engineers Association Association
4、of Public Analysts British Edible Pulse Association British Maize Refiners Association Department of Trade and Industry (Laboratory of the Government Chemist) Flour Milling and Baking Research Association Food and Drink Federation Grain and Feed Trade Association Home Grown Cereals Authority Institu
5、te of Brewing Institute of Food Science and Technology Intervention Board for Agricultural Produce Ministry of Agriculture, Fisheries and Food NABIM National Association of Commodity Cargo Superintendents and Surveyors National Farmers Union Overseas Development Natural Resources Institute Society o
6、f Chemical Industry Ulster Farmers Union United Kingdom Agricultural Supply Trade Association Ltd. Amendments issued since publication Amd. No. Date of issue CommentsBS 4317-18:1988 BSI 09-1999 i Contents Page Committees responsible Inside front cover Foreword ii 1 Scope 1 2 Definitions 1 3 General
7、principles 1 4 Sampling 2 5 Examination of samples 5 6 Expression of results 6 7 Interpretation of results 6 8 Test report 6 Appendix A Suitable data record sheet 7 Table 1 Number of bags to be sampled 4 Table 2 Incubation periods (in days) for the detection of the hidden stagesofinsects in samples
8、of cereals and pulses kept under the suggested conditions 6 Publications referred to Inside back coverBS 4317-18:1988 ii BSI 09-1999 Foreword This Part of BS 4317 has been prepared under the direction of the Food and Agriculture Standards Committee. It is based on ISO6639-1, ISO6639-2 and ISO6639-3
9、published by the International Organization for Standardization (ISO). These International Standards were prepared with the participation of the UK but not approved by the UK, as they refer to ISO6639-4, which describes rapid methods for determination of hidden insect infestation and which it was co
10、nsidered gave insufficiently reliable results. In addition, the UK considered that there was advantage in combining the general principles, sampling and method into a single document. For ease of production the data record sheet in Appendix A is reproduced from ISO6639-3. A British Standard does not
11、 purport to include all the necessary provisions of a contract. Users of British Standards are responsible for their correct application. Compliance with a British Standard does not of itself confer immunity from legal obligations. Summary of pages This document comprises a front cover, an inside fr
12、ont cover, pagesi andii, pages1 to8, an inside back cover and a back cover. This standard has been updated (see copyright date) and may have had amendments incorporated. This will be indicated in the amendment table on the inside front cover.BS 4317-18:1988 BSI 09-1999 1 1 Scope This Part of BS4317
13、describes a method for determining the extent of hidden insect infestation in cereals and pulses in any form of store or vehicle at any level of trade from producer to consumer. The method is suitable for use as a reference method in the calibration of rapid methods. It may be used in cases of dispu
14、te. NOTEThe titles of the publications referred to in this Part of BS4317 are listed on the inside back cover. 2 Definitions For the purposes of this Part of BS 4317 the following definitions apply. 2.1 initial observed infestation those free-living insects that are immediately apparent to the eye w
15、hen the sample is first examined 2.2 hidden infestation those insects which are not visible but which are present within individual grains either because they are at juvenile stages and have developed from eggs laid inside the grains, or because they have entered the interior of individual grains th
16、rough cracks or other damage, usually to feed 2.3 grain cereal grains and/or seeds of pulses 2.4 consignment the quantity of grain delivered at one time and covered by one set of shipping documents. It is composed of one or more lots 2.5 lot a stated quantity of a consignment, to be sampled using a
17、particular sampling plan NOTE 1There is no need to restrict the size of the lot when sampling for hidden 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 more convenient. If the consignment is received i
18、n 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 to be sampled as separate lots. NOTE 2The definition of lot for the purpose
19、s of sampling for determination of hidden infestation differs from the definition of lot relating to sampling of grain and pulses for the determination of other characteristics. 2.6 increment a small quantity of grain taken from a single position in the lot 2.7 bulk sample the quantity of grain obta
20、ined by combining and mixing the increments taken from a specific lot 2.8 laboratory sample the quantity of grain removed from the bulk sample, or a separate increment, and intended for examination 3 General principles 3.1 Some species of insects are especially adapted to attack whole grains and nor
21、mally spend a considerable part of the life cycle, including the entire larval feeding period, inside grains. Other species also take advantage of holes or cracks in grains to enter and feed inside them. These insects constitute a hidden infestation that cannot readily be seen in consignments or sam
22、ples. 3.2 Most insect pests of stored grains are very small, under5mm in length, cryptic in behaviour and dull in colour. Those that fly do so mostly in dull light or at high temperatures. Thus, even when they are living freely outside the grains and do not constitute a hidden infestation as describ
23、ed in3.1, they are not easy to detect unless populations are large enough to induce noticeable activity. 3.3 Being mobile, at least in the free-living form, insects are capable of moving through a bulk of grain and tend to concentrate in those parts of the bulk most favourable for feeding and breedi
24、ng. Such centres of insect activity are not necessarily static; they may expand, contract or move for many complex reasons. The most important reasons are changes in the physical condition of the grain, for example temperature and moisture content, and overcrowding of the insects due to rapid breedi
25、ng. Thus the distribution of insects in a bulk of grain is rarely random, and their detection requires specialist knowledge and techniques.BS 4317-18:1988 2 BSI 09-1999 3.4 For true grain insects that spend the larval stage, and usually the pupal stage, within the grain, the test method is to incuba
26、te samples at a standard temperature and relative humidity and to examine the samples at regular intervals. It is a slow method because it allows each insect to complete its developmental cycle and to emerge as an adult from the grain before it is removed. It can be used reliably for species that no
27、rmally feed within grains, but not for species that occasionally feed in holes or cracks in grains. These may be shaken from the grains or be induced to leave them by the disturbance of handling at any stage of the life cycle and some are likely to be killed in the process. The numbers of such speci
28、es will therefore be underestimated. 4 Sampling 4.1 The methods of sampling cereals and pulses specified in BS4510 and BS4511 are not appropriate for sampling for hidden infestation in cereals and pulses, because of the non-random distribution of insect populations, particularly after a period of pr
29、olonged storage or transportation. 4.2 Special techniques, not relevant or desirable for the purposes of determination of grain quality, for which BS4510 and BS4511 were developed, include selecting samples from the top and outer layer of bags or packages in a stack and sampling from the surface lay
30、er and warmer regions of bulk grain. These are locations in which insect infestation is generally most likely to be found, and therefore justify the departure from the basic principles of representative sampling. Despite these differences, it will be possible in most instances for the same personnel
31、 to use the same equipment to obtain samples for either the determination of grain quality or the determination of hidden insect infestation, or for both purposes, during the same operation. NOTEUsually there is little or no prior information on the size or distribution of any insect population that
32、 may 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 here do not necessarily enable insect populations to be measured precisely, but have been designed to g
33、ive a maximum of information in a practical manner. 4.3 Special care is necessary to ensure that all sampling apparatus is 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 entering the samples, sampli
34、ng apparatus and sample containers. 4.4 Laboratory samples shall be enclosed in sample bags and shall be protected from direct exposure to sunlight, wetting or other extreme environmental conditions. Airtight containers shall not be used for samples as these may cause any insects present to be asphy
35、xiated. 4.5 If related information about the grain, such as moisture content, is required, separate samples shall be taken in accordance with BS4510 or BS4511 or other relevant standards and shall be packaged accordingly. 4.6 Apparatus for sampling 4.6.1 Device for sampling from grain flowing in bul
36、k, which will extract samples continuously from the entire cross section of the grain flow, giving samples of all particle sizes from the lot. This can be either a sophisticated electrically operated automatic sampler (see BS6298) or a falling stream sampler (Pelican type) (see BS4510) operated by h
37、and. 4.6.2 Device for sampling from the surface of static bulk grain, a hand scoop (see BS4510). 4.6.3 Device for sampling bulk grain in depth, either a cylindrical sampler (divided bulk probe) (seeBS4510) or an electrically operated suction sampler. 4.6.4 Device for sampling grain in bags, either a
38、 cylindrical sampler or a sample divider. If the bag to be sampled weighs less than10kg, a sample divider (conical divider (Boerner type) or multiple-slot divider) as shown in BS4510 should be used to obtain the increments. In the case of larger bags, a large, continuous flow sample divider may be u
39、sed. NOTESampling spears (open triers) are not suitable for sampling for this purpose. 4.6.5 Sample bags, of close woven cloth with tie ribbons, each measuring approximately40cm long and30cm wide, which have been cleaned and disinfested. NOTESample bags can be cleaned by thoroughly brushing inside a
40、nd out, and, if necessary, by washing and drying. They may be disinfested by being left in an oven at103 C for2h. Immediately after being allowed to cool in the oven, the bags should be placed into sterile, screw-top jars for storage until required. 4.6.6 Metal seals and sealing equipment, for seali
41、ng the sample bags. 4.7 Place and time of sampling Samples shall be taken at any point from farmer to final destination. NOTEIf samples are to be taken at different points in the distribution chain, it is useful to establish standardized sampling operations at all points and to collect the sampling
42、data in order to form a more comprehensive picture.BS 4317-18:1988 BSI 09-1999 3 Sampling is most effectively carried out as the commodity is moved into and out of the storage structure or transit vehicle (railway wagons, lorries, containers, ships, lighters, etc.). If a commodity is stored for a lo
43、ng period in bulk or in bags, sampling becomes more difficult but more important. Samples shall not be taken from grain that has been stored for less than3weeks in order to allow time for migration of insects. 4.8 Pre-sampling inspection and identification of lots 4.8.1 The identification of the lot
44、 or lots to be inspected and the species of insects (live or dead) to be sought shall be specified. NOTE 1In the case of grain for export, due regard should be paid to any regulations concerning scheduled pests, and tolerances for such pests, in the importing country. Internal trade may also be affe
45、cted by such regulations. NOTE 2It should be borne in mind that it is possible for a hidden infestation to mature and produce large numbers of free-living adults shortly after a lot has been reported to be free from infestation or only lightly infested. Rapid changes in insect population density or
46、distribution can result from variations in ambient temperature, cross-infestation or some other reason. 4.8.2 Particularly in order to help in the assessment of samples, inspection of bags, buildings, structures and transport shall be carried out before sampling the grain and information recorded in
47、cluding the temperature of the grain. Any living insects found in the samples being taken shall be collected and forwarded in a container separate from grain to the laboratory for identification. 4.9 Sampling of bulk grain 4.9.1 Extracting samples from moving bulks. At flow rates of100t/h or less, t
48、he lot to be sampled shall be not greater than5000kg (5t) or smaller than1000kg (1t) and the increments shall be equivalent to a minimum of1kg per1000kg. Higher rates of flow may require the designation of larger lot sizes, to allow the sampling equipment to cope, but the size of the increments shal
49、l be proportionately the same. An automatic sampling device or falling stream sampler (Pelican type) (4.6.1) shall be used for collecting samples from free-falling grain. If there is no point of free-fall, it is permissible to use alternative mechanical sampling equipment or hand scoops (4.6.2). NOTESamples obtained from conveyor belts are less representative than those extracted from a point of free fall. 4.9.2 Extracting samples from static bulks 1) . In vertical bulk storage bins, if the air temperature above the grain is below15 C, sampling for hidden infestation
