FIRST SCHEDULE
SAMPLING OF WHEAT GRAINS IN BAGS
1.The standard sack sampler shall be a tapered steel tube capable of drawing representative samples when inserted through a gunny bag filled with wheat grains, and of a type approved by the Kenya Bureau of Standards.2.Primary samples shall be drawn from different parts of the bag (for example, top, middle and bottom) by means of a standard sack sampler. The sampler shall be put into each sack towards the centre and to the full extent on the inverted slotted opening and then turned through 180 degrees. The sample shall then be withdrawn and the contents emptied into a container. The quantity of the grading sample drawn from a specific consignment shall not be less than two litres in volume. The contents of any bag which differs in any respect from this sample, shall be graded separately.SECOND SCHEDULE
SAMPLING OF WHEAT GRAINS IN BULK
1.A bulk sampler shall be a type of device capable of drawing a representative sample from a bulk wagon, lorry or moving stream of wheat grains, and be of a type approved by the Kenya Bureau of Standards. The method of obtaining samples from the above containers shall be as follows—(i)probe in the centre of the container;(ii)probe from 1 to 2 metres back from the door-post towards the end of the container and 60 cm from one side of the container;(iii)probe from 1 to 2 metres from the same end of the container and approximately 60 cm from the opposite side of the container as in (ii);(iv)probe same as in (ii) and (iii) except in opposite end and sides of the container;(v)a sample may ‘be taken after direct transfer or "drop-back", or by binning run method at the time of loading, or unloading as mentioned above.2.Each probed sample of the grain shall be examined for uniformity in respect of group odour, moisture content, weather damage, heat damage and infestation with insects or other pests. If all portions are found to be uniform they shall be composited into one sample representing the entire consignment. If any portion is found to differ in grades or in quality characteristics, further sampling shall be dune to establish the fractional part of the entire consignment that is different and the result shall be indicated.THIRD SCHEDULE
MECHANICAL SAMPLE DIVIDER
1.The mechanical sample divider shall be the apparatus used for randomly dividing a sample of wheat grains into equal separate portions, and be of a type approved by the Kenya Bureau of Standards.2.The usage of this apparatus shall be according to the manufacturers’ instructions.FOURTH SCHEDULE
QUARTERING
1.The quartering apparatus is constructed of two pieces of rigid material measuring approximately 45 cm. x 3 cm. each. They are joined at their centres to intersect at right angles in one plane.2.The sample shall be thoroughly mixed and spread evenly in layers over a flat surface and divided into four approximately equal quarters by placing the quartering apparatus over the sample. Two quarters situated diagonally across the dividing line shall be combined together to constitute the sample. Further operation of the quartering apparatus using the above method shall be done where the original quartered sample is too large.FIFTH SCHEDULE
DETERMINATION OF GRADE MASS FROM THE SAMPLE
1.(1) The apparatus consists of four different pieces of equipment, as described below.If other apparatus to that described proves to be accurate in determining grade mass, then, with Kenya Bureau of Standards approval, this apparatus can be authorized for use in the industry.(2)The funnel.—This shall be a metal funnel and shall conform to the following dimensions—top diameter (internal) ................................... 21.5 cm. ± 0.5 cm.bottom diameter ............................................ 3.3 cm. ± 0.2 cm.perpendicular height between top and bottom openings ....... 16.5 cm. ± 0.5 cm.The funnel shall be supported on three fixed metal legs and the lower aperture shall be closed by means of a metal slide capable of being freely withdrawn. The legs shall be adapted to support the funnel on the rim of the measure so that the vertical distance between the underside of the slide and the top of the brass measure is 3.8 cm. ± 0.2 cm.(3)The Metal Measure.—This shall be a cylindrical measure of rigid construction with the seam soldered so that it retains water. It shall have the following internal dimensions—capacity shall be between 500 and 502 millilitres, diameter ...................... 7.2 cm. ± 0.3 cm.depth ............................................................................ 12.3 cm. ± 1.0 cm.(4)The weighing balance shall be as described in the Eight Schedule.(5)The Stroker—Shall be a cylindrical piece of wood having a length of approximately 15 cm and diameter of approximately 2.5 cm.2.All relevant provisions of the Weights and Measures Act (Cap. 513) and the Rules thereunder shall be applicable to the weighing instruments and the other apparatus described above.3.(1) The metal measure shall be first filled to over-flowing capacity with the sample of wheat grain to be measured by using a scoop or other suitable means. The over-flowing measure of wheat grain shall then be transferred to the funnel with the slide previously closed. The measure shall be stood on a firm level surface free from any vibration. The funnel containing the sample shall be placed on top of the measure. The slide shall then be withdrawn fully and smartly. After the funnel has been emptied it shall be removed from the measure without jarring the measure. The measure shall then be struck by placing the stroker horizontally on the edge of the measure and sweeping it across the top in one light semi-circular movement.(2)The contents of the metal measure shall then be transferred to the pan of the weighing instrument and the mass read. The mass shall be read to the nearest 5 gram division. The mass of the grain must be determined twice on each sample; if the two weightings do not agree the test must be repeated:Provided that the mass of grain ascertained by the above procedure can be converted to the hectolitre mass, as set out in Table 3.SIXTH SCHEDULE
MOISTURE DETERMINATION APPARATUS
1.The electronic moisture meter shall be of a type approved by the Kenya Bureau of Standards.(2)It shall be used in the manner laid down by the manufacturers subject to the standards of the Kenya Bureau of Standards which may require changes in procedure to ensure that readings are consistent with the standard air-oven method.The performance of each meter shall be checked at least biannually, to ensure that it reads correctly, against the oven method.2.The formula used for computing percentage loss in mass is as follows—100. x (M1 — M2)________100. — M2Where MI = Initial percentage moisture contentand M2 = Final percentage moisture contentSEVENTH SCHEDULE
THE SIEVE AND ‘METHOD FOR DETERMINING PERCENTAGE OF BROKEN GRAINS
1.Apparatus—the sieve shall measure internally approximately 25 cm square by 5 cm. deep. The sieve shall be perforated with slots 1.6 mm wide and 9.5 mm long. In use it shall be fitted to a catch-box below and with a suitable lid on top to avoid spillage of any fraction being tested.2.Description of the Sieving Test.—(1) A sample shall be made up of half a litre wheat grain already weighed for the hectolitre mass test which shall be used for determining shrivelled and broken grain.(2)The sieve shall be held level in both hands directly in front of the body with the elbows close to the sides. It shall be held so that the grain moves lengthwise with the perforation. The sieve shall be moved approximately 25 cm from right to left and returned from left to right to complete an operation, while maintaining the horizontal place.(3)The complete operation shall be repeated thirty times at the above rate and the shaking shall continue for approximately 15 seconds, after which the sieve shall be given two taps on the side of the box to clear the perforations.(4)The broken grains, as defined under regulation 2(1) which have passed through the screen and are found in the sieve box, shall be weighed. This mass divided by the original mass of the half litre of grain and multiplied by 100. shall be reported as the"percentage of broken grains".EIGHTH SCHEDULE
WEIGHING BALANCES
1.The weighing instrument used for determining the mass of wheat grains containing in the measure shall be of a self-indicating pattern which is acceptable by the Weights and Measures Department and the Kenya Bureau of Standards. For the purposes of assizing and stamping, the chart of the weighing instrument shall be graduated to a weighing capacity of 500 grams by 5 grams subdivisions, which shall be less than 2 mm apart. The weighing instrument shall be provided with a detachable goods pan in the form of a scoop.2.The balance for assessing defects in wheat grain, as set out in Tables 1 and 2, shall have a capacity of 50 grams, with a minimum accuracy of 0.1 gram and of a type approved by the Kenya Bureau of Standards.3.All relevant provisions of the Weights and Measures Act (Cap. 513)and the rules made thereunder, shall apply to the weighing instruments.NINTH SCHEDULE
GRADING SAMPLE
1.The grading sample, with a minimum volume of 2 litres, shall be obtained as set in the First and Second Schedules.2.(1) The sequence of determining factors to reach the final wheat grade, shall be as follows—(c)quartering method—retain two quarters separately for analysis;(d)use first quarter to determine the following—(e)express the results as a percentage of the grade mass.(2)Use the second quarter to repeat determination of grade mass. Then, weigh two samples of 25 grams each from this quarter—(i)Use the first of these samples to determine the following defects as set out below—(b)earth, sand and stones;(ii)The perecentage of these defects be determined by hand picking from the sample in the order above and separated from each other. The defective materials separated are then weighed to a tolerance of 0.1 gram and the defects calculated and expressed as a percentage of the total mass of the 25 gram sample.(iii)Use the second of these samples to determine weather damage percentage as set out in the Tenth Schedule.TENTH SCHEDULE
RECOGNITION OF WEATHER DAMAGED AND HEAT DAMAGED WHEAT
1.Weather Damaged Wheat.—Take the sample referred to in the Ninth Schedule and spread this out on a light-green tile. Examine every grain on its dorsal surface only (each grain has a ventral surface, sides and dorsal, or back, surface). Separate weather damaged grain consisting of the following types of discolouration, physical damage and mould infection, provided that 1/3 or more of the dorsal surface of the grain is affected.2.Type of Discolouration—(i)Parts of the grain near the brush end are grey, greyish black or dark brown.(ii)Parts of the grain are distinctly yellow.(iii)Parts of the grain are orange red.Grains which are bleached or pale but otherwise sound are not considered to be discoloured. The condition known as black point, which is a brown, dark brown or almost black disc at the embryo end of the grain is not considered be discolouration due to weather damage.3.Physical Damage—(i)Badly distorted grains (except shrivelled grain).(ii)Grains in which part of the seed coat covering the endosperm is actually torn or peeled off. (The condition in which the seed coat appears loose and often bubbly, but is not actually torn, must be considered to be physically damaged.)4.Mould Infection—(i)Small separate black spots scattered over the surface of the grain due to leaf blight (pyronophera trichostome).(ii)Greyish black discolouration of the brush end of the grain due to black mould(Cladosporium herborum).(iii)Pinkish red areas due to scab (Fusarium graminearum).In cases where mould infection appears as spots on the grain, the total area in which the spots are spread shall be considered.5.Heat Damage:Heat damaged wheat displays the following defects, odour, colour, texture and chemical change.(i)Odour.—A typical characteristic smell akin to that of roasted wheat.(ii)Colour.—The surface colour, depending on the extent of heat damage, varies from reddish brown to black. The endosperm colour is not normal white or opaque, but is brownish.(iii)Texture.—The affected grain is cut by a blade, or preferably by a grain cutter, and the cut surface may display a crumbly and brittle texture depending on the extent of heat damage.(iv)The protein and starch has been denatured and this can be verified through rheological tests.TENTH SCHEDULE
RECOGNITION OF WEATHER DAMAGED AND HEAT DAMAGED WHEAT
1.Weather Damaged Wheat.—Take the sample referred to in the Ninth Schedule and spread this out on a light-green tile. Examine every grain on its dorsal surface only (each grain has a ventral surface, sides and dorsal, or back, surface). Separate weather damaged grain consisting of the following types of discolouration, physical damage and mould infection, provided that 1/3 or more of the dorsal surface of the grain is affected.2.Type of Discolouration—(i)Parts of the grain near the brush end are grey, greyish black or dark brown.(ii)Parts of the grain are distinctly yellow.(iii)Parts of the grain are orange red.Grains which are bleached or pale but otherwise sound are not considered to be discoloured. The condition known as black point, which is a brown, dark brown or almost black disc at the embryo end of the grain is not considered be discolouration due to weather damage.3.Physical Damage—(i)Badly distorted grains (except shrivelled grain).(ii)Grains in which part of the seed coat covering the endosperm is actually torn or peeled off. (The condition in which the seed coat appears loose and often bubbly, but is not actually torn, must be considered to be physically damaged.)4.Mould Infection—(i)Small separate black spots scattered over the surface of the grain due to leafblight (pyronophera trichostome).(ii)Greyish black discolouration of the brush end of the grain due to black mould (Cladosporium herborum).(iii)Pinkish red areas due to scab (Fusarium graminearum).In cases where mould infection appears as spots on the grain, the total area in which the spots are spread shall be considered.5.Heat Damage:Heat damaged wheat displays the following defects, odour, colour, texture and chemical change.(i)Odour.—A typical characteristic smell akin to that of roasted wheat.(ii)Colour.—The surface colour, depending on the extent of heat damage, varies from reddish brown to black. The endosperm colour is not normal white or opaque, but is brownish.(iii)Texture.—The affected grain is cut by a blade, or preferably by a grain cutter, and the cut surface may display a crumbly and brittle texture depending on the extent of heat damage.(iv)The protein and starch has been denatured and this can be verified through rheological tests.
