ISO-6639-4-1987.pdf
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1、INTERNATIONAL STANDARD INTERNATIONAL ORGANIZATION FOR STANDARDIZATION ORGANISATION INTERNATIONALE DE NORMALISATION MEXflYHAPOaHAR OPTAHM3AMR IlO CTAHAAPTM3AMM Cereals and pulses - Determination of hidden insect infestation - Part 4: Rapid methods C or b) grain products with moisture contents greater
2、 than 15 % (m/m), because of the risk of carbon dioxide produced by the products themselves and by micro-organisms in- terfering with the results. In addition, the method is not applicable to the rapid testing of grain products on to which carbon dioxide has already been adsorbed in large quantities
3、, for example grain stored in a con- fined atmosphere or when there are clear external indications of heavy infestation. The method can be used for coarsely milled or kibbled grain products, provided that they have been sieved before testing to remove fine particles and loose insects. The method doe
4、s not permit the presence of dead adults, pupae, larvae or eggs to be detected. Section two: Ninhydrin method (clauses 10 to 16) The method is applicable to any dry grain prone to internal insect infestation, particularly wheat, sorghum, rice and similar sized grains. Large grains, such as maize, ha
5、ve to be partially broken (kibbled) before they can be tested. This treatment of large grains can cause some insects to be lost or fragmented, thus rendering the interpretation of results unreliable. Numbers of eggs and young larvae may be underestimated, but, in this respect, the method is no less
6、efficient than any other. Section three: Whole grain flotation method (clauses 17 to 24) The method is suitable for detecting hidden infestation in most cereals and pulses but only on a qualitative basis. Section four: Acoustic method (clauses 25 to 31) The method is suitable for detecting living in
7、sect adults and larvae feeding inside grains. It does not permit dead adults and larvae or living eggs and pupae (non-feeding stages) to be detected. Section five: X-ray method (clauses 32 to 36) The method is suitable for detecting living and dead larvae and adults within grains. Insects which have
8、 been recently killed (for example by fumigation) may be difficult to distinguish from those still living. 2 References IS0 520, Cereals and pulses - Determination of the mass of 7 CKX) grains. IS0 565, Test sieves - Woven metal wire clo tb, perforated plate and electroformed sheet - Nominal sizes o
9、f openings. IS0 712, Cereals and cereal products - Determination of moisture con tent (Routine reference method). IS0 950, Cereals - Sampling (as grain). IS0 951, Pulses in bags - Sampling. Copyright International Organization for Standardization Provided by IHS under license with ISO Licensee=NASA
10、Technical Standards 1/9972545001 Not for Resale, 04/19/2007 23:53:18 MDTNo reproduction or networking permitted without license from IHS -,-,- IS0 6639-4 : 1987 (E) Section one: Method by determination of carbon dioxide production 3 Principle Incubation of a test portion of the material at a standar
11、d temperature, and estimation, by a gasometric method or an infra-red method, of the amount of carbon dioxide generated during a standard period as a measure of the total metabolism of the material. NOTE - This method is based on work in which it was shown that respiration could be used to detect in
12、sects in produce and that the volume of airspace is approximately constant in bulk grain packed tight. The metabolic rate of dry grain, or a grain product, is very low. That of insects is so much higher that the generation of carbon dioxide in dry grain or grain product can be regarded as a sign of
13、infestation, provided that care has been taken to avoid contamination with this gas and to ensure that adsorption by the grain is minimized. 4 Apparatus 4.1 Sieve, of suitable aperture size such that fine particles and insects can pass but the material under test is retained (see IS0 565). 4.2 Balan
14、ce, accurate to 0,l g. 4.3 Apparatus for gasometric analysis (see figure l). 4.3.1 Airtight sample containers, of capacity not ex- ceeding 750 ml. Each container shall be closed with a rubber septum. 4.3.2 Syringes and needles, for withdrawing samples of in- terstitial air. The syringes shall be com
15、pletely airtight and shall be of sufficient capacity for the analysis. All-glass syringes of capacity 20 ml are suitable. 4.3.3 Incubator or climatic chamber, capable of being maintained at 25 + 1 OC (see 4.4.1). 4.3.4 Gas analysis apparatus, su itable for measuring bon dioxide concentrations to wit
16、hin +0,2 % WVL car- 4.4 Apparatus for infra-red gas analysis (see figure 2). 4.4.1 Controlled climate room. The analytical apparatus should be housed in a room having controlled temperature and relative humidity, preferably at 25 + 1 OC and a relative humidity of 70 + 5 %. - 4.4.2 Infra-red gas anal
17、yser, with two interchangeable measurement ranges for carbon dioxide (0 to 50 PI/I and 0 to 500 PI/I), capable of operating with dry air as the carrier gas supplied by a compressed air cylinder, an air pressure line or a leakproof diaphragm pump at a flow rate of 2 000 ml/min. 4.4.3 Airtight sample
18、containers, of capacity not ex- ceeding 750 ml. These containers comprise a cylinder made of gasproof material, approximately 100 mm in diameter, sealed at the bottom and accommodating a removable lid with an airtight closure at the top (see 4.3.11, having two orifices with nozzles permitting air to
19、 be introduced into the lower part of the cylinder after connection to the purified air line (see figure 2) and to be expelled at the top. 4.4.4 Supply of compressed dry air (air pressure line, com- pressed air cylinder or diaphragm pump) with a pressure- reducing valve. A flow-regulating valve and
20、a flowmeter are necessary in the circuit. 4.4.5 Three-way valves, manually or electrically controlled. 4.4.6 Air washing and drying tubes, installed in the circuit before the sample container. The washer comprises a flask to allow the air to be bubbled through 10 % (W/IV) sodium hydroxide solution.
21、The desiccator contains desiccant, for example anhydrous calcium chloride. 4.4.7 Moisture indicator, placed between the sample con- tainer and the analyser (silica gel with saturation indicator). 5 Sampling Use samples obtained as described in IS0 6639/2. 6 Procedure 6.1 Preparation of test sample U
22、se the sieve (4.1) to remove any fine particles and insects from the sample. If required, the insects may be identified and the number of adults, pupae and larvae recorded separately for each species. In order to bring the sample to a suitable condition for testing, keep it for 24 h in the incubator
23、 (4.3.31, controlled at 25 OC, or in the controlled climate room (4.4.1) in a close-woven cloth bag, or a wide-mouthed jar, tray or open tin, suitably covered to prevent the entry or escape of free-living insects, while allowing exchange of air (see IS0 6639/3, subclause 5.4). Before preparing the a
24、irtight sample container (6.21, re-sieve the sample to remove any insects which may have emerged during the preparatory period. Spread the sample thinly on a tray or other suitable flat surface, and leave exposed to air for 15 to 30 min (to permit adsorbed carbon dioxide to escape). Airing is less i
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