1、BRITISH STANDARD BS4317-29: 1993 ISO11050: 1993 Methods of test for Cereals and pulses Part29: Determination of impurities of animal origin in wheat flour and durum wheat semolina UDC 664.641.12+664.762:544.869BS4317-29:1993 This British Standard, having been prepared under the directionof the Agric
2、ulture andFood Standards Policy Committee, was published underthe authority of the Standards Board and comes intoeffect on 15 October1993 BSI 08-1999 The following BSI references relate to the work on this standard: Committee reference AFC/4 Draft for comment91/55373 DC ISBN 0 580 22544 5 Committees
3、 responsible for this British Standard The preparation of this British Standard was entrusted by the Agriculture and Food Standards Policy Committee(AFC/-.) to Technical Committee AFC/4, upon which the following bodies were represented: Agricultural Engineers Association Association of Public Analys
4、ts British Edible Pulse Association Department of Trade and Industry(National Weights and Measures Laboratory) Flour Milling and Baking Research Association Grain and Feed Trade Association Home Grown Cereals Authority Institute of Brewing Institute of Food Science and Technology Intervention Board
5、for Agricultural Produce Ministry of Agriculture, Fisheries and Food NABIM National Association of Commodity Cargo Superintendents and Surveyors National Farmers Union Natural Resources Institute Processors and Growers Research Organization Silsoe Research Institute United Kingdom Agricultural Suppl
6、y Trade Association Ltd. Amendments issued since publication Amd. No. Date CommentsBS4317-29:1993 BSI 08-1999 i Contents Page Committees responsible Inside front cover National foreword ii 1 Scope 1 2 Definition 1 3 Principle 1 4 Reagents 1 5 Apparatus 1 6 Sampling 2 7 Procedure 2 8 Expression of re
7、sults 4 9 Repeatability 4 10 Test report 4 Annex A (informative) Definitions and characteristics of fragments found on the filters 5 Annex B (informative) Example of a test report Determination of animal impurities in accordance with ISO11050 8 Annex C (informative) Diagram of the procedure 9 Annex
8、D (informative) Chronology of operations and timetable 10 Figure 1 Separation apparatus 4 Figure A.1 Different types of fragment found on the filters 7 List of references Inside back coverBS4317-29:1993 ii BSI 08-1999 National foreword This Part of BS4317 has been prepared, under the direction of th
9、e Agriculture and Food Standards Policy Committee. It is identical with ISO11050:1993 Wheat flour and durum wheat semolina Determination of impurities of animal origin, published by the International Organization for Standardization(ISO), and in the preparation of which the United Kingdom played a f
10、ull part. Additional information. With reference to clause4, water conforming to grade3 of BS3978:1987 Specification for water for laboratory use is suitable. A British Standard does not purport to include all the necessary provisions of a contract. Users of British Standards are responsible for the
11、ir correct application. Compliance with a British Standard does not of itself confer immunity from legal obligations. Cross-reference International Standard Corresponding British Standard ISO2170:1980 BS5333:1981 Methods for sampling cereals and pulses (as milled products) (Identical) Summary of pag
12、es This document comprises a front cover, an inside front cover, pagesi andii, pages1 to10, 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.BS4
13、317-29:1993 BSI 08-1999 1 1 Scope This International Standard specifies a method for determining the content of impurities of animal origin in wheat flours, with or without additives and having an ash yield not exceeding0,63%(m/m), and in durum wheat semolinas. This method permits the separation and
14、 quantification of contamination of animal origin, e.g.insects at all stages of their development, insect fragments, mites and their fragments, and rodent hairs and their fragments. 2 Definition For the purposes of this International Standard, the following definition applies. 2.1 impurities of anim
15、al origin matter of animal origin(eggs, larvae, nymphs or adults of insects and their fragments, rodent hairs and their fragments, mites and their fragments) separated from the product under the conditions specified in this International Standard 3 Principle Hydrolysis of a test portion with a solut
16、ion of hydrochloric acid at boiling point. Concentration of the insoluble particles(impurities other than those of animal origin may be present) at a water/hydrocarbon interface. Separation by filtration on a filter paper or membrane, microscopic examination, and counting under reflected light, of t
17、he impurities of animal origin. 4 Reagents Use only reagents of recognized analytical grade and distilled or demineralized water or water of equivalent purity. All the reagents used shall be filtered carefully before use or after their preparation. Such filtration may be performed using a filter clo
18、th with a maximum mesh size of104m to304m and which is resistant to acids and solvents(of the nylon or polyethylene fibre type). 4.1 Ethanol or methanol, 95%(V/V). 4.2 Ethanol or methanol solution, 50%(V/V). 4.3 Ethanol/glycerol,1+1 mixture by volume. 4.4 Hydrochloric acid solution, concentrated ( 2
19、0 =1,18g/ml). 4.5 Paraffin oil (known as “Vaseline oil”), fluid, having a viscosity not exceeding60mPas(60cP) at20 C. 4.6 Liquid detergent, non-foaming. 4.7 Liquid detergent,1%(V/V) solution of the detergent(4.6) in a washing bottle. 5 Apparatus Usual laboratory apparatus and, in particular, the fol
20、lowing. 5.1 Separating funnels, conical, of1000ml capacity, fitted with a non-lubricated tap with a flexible tube and a Mohr clip(rubber-tube clip) (seethe recommended set-up shown in Figure 1). 5.2 Tall-form beaker, of800ml capacity, fitted with a watch glass made of pyrex and of appropriate dimens
21、ions to serve as a lid. 5.3 Crystallizing dish or pan, of at least5litre capacity, and of a height slightly less than that of the beaker(5.2), suitable for use as a cooling bath. 5.4 Graduated cylinders, of25ml,50ml and500ml capacity. 5.5 Washing bottles, of1litre capacity, graduated in50ml incremen
22、ts, and fitted with a flexible tube. 5.6 Stretchable protective film, waxed or made of a plastic material. 5.7 Filter paper, ash-free, with rapid filtration characteristics 1) , of diameter corresponding to that of the filtration unit(5.8)(i.e.50mm or90mm), or filtration membrane, of47mm to50mm diam
23、eter, made of cellulose nitrate and having a porosity of54m or84m, on which fine parallel lines are drawn, spaced5mm apart, using a ball-point pen or hard lead pencil. 5.8 Filtration unit, of the Bchner funnel type, suitable for accommodating the filter(5.7), and fitted with a conical adaptor bung f
24、or connection to the filtration flask(5.16). 5.9 Analytical balance, accurate to within0,1g. 5.10 Optical microscope or stereoscopic microscope, known as a “binocular magnifying glass”, capable of producing magnifications close to 25 and 50, of very high optical quality, used in conjunction with a)
25、eyepieces, producing a magnification of 15 or 20(thus enabling a total maximum magnification of the object being observed of 75or 80 depending on the model), and b) a micrometer eyepiece, to measure the dimensions of any impurities. 1) Whatman41 is an example of a suitable filter paper available com
26、mercially. This information is given for the convenience of users of this International Standard and does not constitute an endorsement by ISO of this product.BS4317-29:1993 2 BSI 08-1999 5.11 Petri dish, sterile, made of plastic or glass, with a diameter of90mm. 5.12 Fine needle, made of steel, mou
27、nted in a needle-holding chuck. 5.13 Glass rod, fitted with a rubber or plastic protective end. 5.14 Magnetic stirrer/heater, thermostatically controlled, enabling water to be brought to boiling point. 5.15 Spring clips, suitable for holding the filter papers or filtration membranes(5.7). 5.16 Filtr
28、ation flask, of1litre capacity, capable of being connected preferably to the vacuum pump(5.18), or to a water suction pump(5.18). 5.17 Dropper 5.18 Vacuum pump, enabling a residual pressure of below1000Pa(10mbar) to be achieved or, if this is not available, a water suction pump. NOTE 1The duration o
29、f filtration will need to be increased considerably if a water suction pump is used. 5.19 Oven, capable of being maintained at37 C to40 C. 6 Sampling For the purposes of this test method, it is essential that all equipment used for sampling was thoroughly cleaned between each sampling operation by u
30、sing, for example, filtered compressed air and not by using brushes or textile materials. It is strongly recommended that users of this International Standard ascertain, where possible, that this requirement was met during the sampling procedure. Sampling is not part of the method specified in this
31、International Standard. A recommended sampling method is given in ISO2170 2) . A laboratory sample of at least600g is required. 7 Procedure IMPORTANT All handling operations shall take place in clean premises, away from air currents, or preferably beneath a non-ventilated canopy. All the apparatus s
32、hall be washed in filtered water, rinsed, drained until dry and then covered with a protective film(5.6) until use. 7.1 Test portion With the laboratory sample still in its packaging, mix it thoroughly using a long-handled spatula. By taking samples from several places, weigh50g of the product into
33、the beaker(5.2). 7.2 Hydrolysis 7.2.1 Add100ml of filtered water, a little at a time, to the test portion in the beaker, whilst stirring continuously with the glass rod(5.13) to avoid the formation of lumps. Rinse the sides of the beaker and the glass rod with200ml of filtered water. Then place the
34、glass rod in a container to protect it from dust, for example in a cylinder fitted with a lid. 7.2.2 Place the beaker on the magnetic stirrer(5.14). Introduce the magnetic bar, previously rinsed in filtered water, and then regulate the stirrer to a low speed of rotation. Add to the solution, a littl
35、e at a time,20ml of concentrated hydrochloric acid(5.4), measured in a graduated cylinder(5.4). Cover the beaker with a watch glass. Switch on the heating element of the magnetic stirrer and slowly bring the contents of the beaker to boiling point(to avoid carbonization due to formation of a starch
36、paste). When a smooth paste has been achieved, add30ml of paraffin oil(4.5) measured in a graduated cylinder(5.4). Allow to boil for30min, with gentle stirring. 7.2.3 Cover the beaker with protective film(5.6) and allow the contents to cool to near-ambient temperature in the crystallizing dish or pa
37、n(5.3) in which cold water is circulating. 7.3 Separation of impurities 7.3.1 Set up the separating funnels(5.1) in such a way that the upper funnel drains directly into the lower funnel(see Figure 1). 7.3.2 Pour30ml of paraffin oil(4.5) into the lower separating funnel. 7.3.3 Remove the magnetic ba
38、r from the beaker and rinse it using the alcohol solution(4.2), collecting the rinsings in the beaker. Transfer the contents of the beaker with the aid of the glass rod(7.2.1) into the upper separating funnel. Rinse the glass rod and the walls of the beaker using the washing bottle(5.5), with30ml to
39、50ml of the alcohol solution(4.2), scraping carefully the walls of the beaker with the glass rod, and transfer the rinsings to the upper separating funnel. If necessary, the cleaning operation should be completed using about10ml of ethanol or methanol(4.1), using the same procedure as described abov
40、e. 7.3.4 Make up the contents of the upper separating funnel with the alcohol solution(4.2) in such a way that the level of the liquid reaches the widest part of the funnel(100ml to250ml of the alcohol solution will have to be added, depending on the quantities used during rinsing). 2) ISO2170:1980,
41、 Cereals and pulses Sampling of milled products.BS4317-29:1993 BSI 08-1999 3 Remove the separating funnel from its support and, keeping it vertical, swirl the contents for2min using a circular motion so as to cause the liquid to flow in a thin layer around the walls. Replace the separating funnel on
42、 its support and leave it to stand for at least1h. 7.3.5 Drain off by means of the Mohr clip the major part of the aqueous phase into the lower separating funnel, allowing a few millilitres (i.e.a layer about3cm thick) to remain in the upper funnel. 7.3.6 Remove the lower separating funnel from its
43、support and swirl the contents in the same way as described in7.3.4 for the upper separating funnel. Replace the separating funnel on the stand and leave it to stand for1h. 7.3.7 Discard the major part of the aqueous phase, allowing a few millilitres (i.e.a layer about3cm thick) to remain in the low
44、er funnel. 7.3.8 Add directly to the upper separating funnel300ml of the alcohol solution(4.2), allowing the solution to run down the wall. Swirl the contents for2min, in the same way as described in7.3.4, and leave to stand for1h. 7.3.9 Drain off the major part of the aqueous phase into the lower s
45、eparating funnel, allowing a few millilitres(i.e.a layer about3cm thick) to remain in the upper funnel. 7.3.10 Add300ml of the alcohol solution(4.2) to each of the separating funnels, allowing the solution to run down the wall. Swirl the contents of each funnel for2min, in the same way as described
46、in7.3.4, and leave to stand for30min. 7.3.11 Discard the major part of the aqueous phase in each funnel, allowing a few millilitres to remain. 7.3.12 Repeat the operations described in7.3.10 if necessary. NOTE 2The contents of the two funnels will be ready for filtration at approximately the same ti
47、me. 7.4 Filtration 7.4.1 Place the filter(5.7) in the filtration unit(5.8). Attach the unit to the filtration flask(5.16) and connect the flask to the vacuum pump(5.18). Moisten the filter with a small quantity of paraffin oil(4.5) and switch on the vacuum pump. 7.4.2 Transfer the contents of the tw
48、o separating funnels directly into the filtration unit. 7.4.3 Add, using the dropper(5.17), about four drops of the detergent(4.6) to the upper separating funnel, and then add10ml of filtered water. Fit a bung to the funnel and mix the contents vigorously by swirling them around the wall and inverti
49、ng the funnel several times. Replace the separating funnel on its support and allow the washing product to flow into the lower separating funnel. Fit a bung to the lower separating funnel and mix its contents as described above. Replace the separating funnel on its support, and allow the rinsing product to flow into the filtration apparatus. 7.4.4 Rinse the walls of each separating funnel, using the washing bottle(5.5), with20ml of the alcohol solution(5.2), rinsing first the upper separating funnel and then the lower separating funnel. Allow the solut
