1、BRITISH STANDARD BS 4401-1: 1998 ISO 936:1998 Methods of test for meat and meat products Part 1: Determination of total ash ICS 67.120.10BS4401-1:1998 This British Standard, having been prepared under the directionof the Consumer Products and Services Sector Board, was published under the authority
2、of the Standards Boardand comes into effect on 15October 1998 BSI 04-1999 ISBN 0 580 30373 X National foreword This British Standard reproduces verbatim ISO936:1998 and implements it as the UK national standard. It supersedes BS4401-1:1978 which is withdrawn. The UK participation in its preparation
3、was entrusted to Technical Committee AW/6, Chemical analysis of meat and meat products, which has the responsibility to: aid enquirers to understand the text; present to the responsible international/European committee any enquiries on the interpretation, or proposals for change, and keep the UK int
4、erests informed; monitor related international and European developments and promulgate them in the UK. A list of organizations represented on this committee can be obtained on request to its secretary. Cross-references The British Standards which implement international or European publications ref
5、erred to in this document may be found in the BSI Standards Catalogue under the section entitled “International Standards Correspondence Index”, or by using the “Find” facility of the BSI Standards Electronic Catalogue. A British Standard does not purport to include all the necessary provisions of a
6、 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 front cover, pages i and ii, theISO title page, page ii
7、, pages 1 to 4 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. Amendments issued since publication Amd. No. Date CommentsBS4401-1:1998 BSI 04-1999 i Contents Page
8、National foreword Inside front cover Foreword ii 1 Scope 1 2 Normative reference 1 3 Definition 1 4 Principle 1 5 Reagents 1 6 Apparatus 1 7 Sampling 1 8 Preparation of test sample 1 9 Procedure 1 10 Calculation 2 11 Precision 2 12 Test report 3 Annex A (informative) Bibliography 4ii blankBS4401-1:1
9、998 ii BSI 04-1999 Foreword ISO (the International Organization for Standardization) is a worldwide federation of national standards bodies (ISO member bodies). The work of preparing International Standards is normally carried out through ISO technical committees. Each member body interested in a su
10、bject for which a technical committee has been established has the right to be represented on that committee. International organizations, governmental and non-governmental, in liaison with ISO, also take part in the work. ISO collaborates closely with the International Electrotechnical Commission (
11、IEC) on all matters of electrotechnical standardization. Draft International Standards adopted by the technical committees are circulated to the member bodies for voting. Publication as an International Standard requires approval by at least 75% of the member bodies casting a vote. International Sta
12、ndard ISO 936 was prepared by Technical Committee ISO/TC 34, Agricultural food products, Subcommittee SC 6, Meat and meat products. This second edition cancels and replaces the first edition (ISO936:1978), which has been technically revised. Annex A of this International Standard is for information
13、only. Descriptors: Agricultural products, animal products, food products, meat, meat products, tests, ash determination, combustion analysis.BS4401-1:1998 BSI 04-1999 1 1 Scope This International Standard specifies a method for the determination of the total ash from all kinds of meat and meat produ
14、cts, including poultry. 2 Normative reference The following standard contains provisions which, through reference in this text, constitute provisions of this International Standard. At the time of publication, the edition indicated was valid. All standards are subject to revision, and parties to agr
15、eements based on this International Standard are encouraged to investigate the possibility of applying the most recent edition of the standard indicated below. Members of IEC and ISO maintain registers of currently valid International Standards. ISO 3696:1987, Water for analytical laboratory use Spe
16、cification and test methods. 3 Definition For the purposes of this International Standard, the following definition applies. 3.1 total ash from meat and meat products mass of the residue obtained after incineration at a temperature of (550 25)C under the operating conditions specified in this Intern
17、ational Standard, divided by the mass of the test portion NOTEThe mass fraction of ash is usually expressed as a percentage. 4 Principle A test portion is dried, carbonized and then incinerated at (550 25)C. After cooling, the mass of the residue is determined. 5 Reagents Use only reagents of recogn
18、ized analytical grade, unless otherwise specified. 5.1 Water, complying with at least grade 3 in accordance with ISO 3696. 5.2 Hydrogen peroxide, 30%. 6 Apparatus Usual laboratory apparatus and, in particular, the following. 6.1 Mechanical or electrical equipment capable of homogenizing the laborato
19、ry sample. This includes a high-speed rotational cutter, or a mincer fitted with a plate with apertures not exceeding 4,0mm in diameter. 6.2 Dish, flat-bottomed, made of porcelain, quartz or metal (e.g.nickel, platinum, stainless steel) or of other material unaffected by the conditions of the test,
20、with a diameter of at least 60 mm, and inclined walls of height at least 25mm. 6.3 Muffle furnace, electrically heated and equipped with a programmable time-temperature controller, and capable of being maintained at (550 25)C. 6.4 Desiccator, containing an efficient desiccant. 6.5 Analytical balance
21、, capable of weighing to the nearest 0,1mg. 6.6 Drying oven, capable of being maintained at(103 2)C (if the muffle furnace has no time-temperature controller). 6.7 Electric hot-plate or a gas flame (if the muffle furnace has no time-temperature controller). 7 Sampling Sampling is not part of the met
22、hod specified in this International Standard. A recommended sampling method is given in ISO3100-1 1. It is important that the laboratory receive a sample which is truly representative and has not been damaged or changed during transport or storage. Start from a representative sample of at least 200g
23、. Store the sample in such a way that deterioration and change in composition are prevented. 8 Preparation of test sample Homogenize the laboratory sample with the appropriate equipment (6.1). Take care that the temperature of the sample material does not rise above 25C. If a mincer is used, pass th
24、e sample at least twice through the equipment. Fill a suitable airtight container with the prepared sample. Close the container and store in such a way that deterioration and change in composition are prevented. Analyse the sample as soon as practicable, but always within 24h after homogenization. 9
25、 Procedure NOTEIf it is required to check whether the repeatability limit (see11.2) is met, carry out two single determinations in accordance with9.1 to9.3. 9.1 Test portion Heat the dish (6.2) for 20min in the muffle furnace(6.3) set at 550C. Allow the dish to cool in the desiccator (6.4) to room t
26、emperature and weigh (m 0 ) on the analytical balance (6.5) to the nearest 0,1mg.BS4401-1:1998 2 BSI 04-1999 Transfer 1,5g to 2g of the prepared test sample (seeclause8) to the dish. Spread it out evenly and without delay weigh (m 1 ) the dish again to the nearest 0,1mg. NOTEIf deemed appropriate by
27、 the analyst, having regard to the nature of the laboratory sample, up to 5g of the prepared test sample may be taken. This should be noted in the test report. If the muffle furnace is provided with a time-temperature controller, proceed in accordance with9.2. If not, proceed in accordance with9.3.
28、9.2 Determination applying muffle furnace with time-temperature controller Place the dish with its contents in the cool muffle furnace (6.3) and gradually raise the temperature of the furnace over 5h to 6h to (550 25)C. Continue the ashing at (550 25)C until the ash has a grey-white appearance. Remo
29、ve the dish from the muffle furnace and allow to cool in the desiccator (6.4) to room temperature. CAUTION Avoid loss of ash when transferring the dish with the ash from the furnace to the desiccator and from the desiccator to the analytical balance. Inspect the ash. If the ash is still black, treat
30、 it with a few drops of hydrogen peroxide (5.2) or water (5.1) and repeat the procedure described in this subclause. If the ash has a grey-white appearance, weigh on the analytical balance (6.5), to the nearest 0,1mg, the dish with its contents (m 2 ). Proceed in accordance with clause10. 9.3 Determ
31、ination applying muffle furnace without time-temperature controller Place the dish with its contents for 1h in the drying oven (6.6) set at 103C. Remove the dish from the oven and place it on an electric hot-plate or over a gas flame (6.7). Heat progressively until the substance carbonizes with the
32、evolution of smoke. Carefully continue carbonization until smoke evolution ceases. The sample material shall neither ignite nor burn with a flame. Transfer the dish to the cool muffle furnace (6.3) and raise the temperature to (550 25)C. After 4h, remove the dish with its contents from the muffle fu
33、rnace and allow to cool in the desiccator(6.4) to room temperature. CAUTION Avoid loss of ash when transferring the dish with the ash from the furnace to the desiccator and from the desiccator to the analytical balance. Inspect the ash. If the ash is still black, treat it with a few drops of hydroge
34、n peroxide (5.2) or water (5.1) and repeat the procedure described in this subclause. If the ash has a grey-white appearance, weigh on the analytical balance (6.5), to the nearest 0,1mg, the dish with its contents (m 2 ). 10 Calculation Calculate the mass fraction of ash of the test sample using the
35、 equation: where Report the result rounded to the nearest 0,01%. 11 Precision 11.1 Interlaboratory test The precision of the method was established by an interlaboratory test carried out in accordance with ISO 5725 2 1) . The results of the interlaboratory test have been published (see reference 6).
36、 The values derived from this test may not be applicable to concentration ranges and matrices other than those given. 11.2 Repeatability The absolute difference between two independent single test results, obtained using the same method on identical test material in the same laboratory by the same o
37、perator using the same equipment within a short interval of time, will in not more than 5% of cases exceed the repeatability limit r given by the equation: r = 0,099 0 % + 0,0093 3 where w a is the mass fraction of ash, as a percentage, of the test sample; m 0 is the mass, in grams, of the empty dis
38、h; m 1 is the mass, in grams, of the dish with the test portion; m 2 is the mass, in grams, of the dish with the ash. 1) ISO 5725:1986 (now withdrawn) was used to obtain the precision data. r is the repeatability limit, as a percentage; is the mean of both results, as a percentage. wa m 2 m 0 () m 1
39、 m 0 () - 100 % = w wBS4401-1:1998 BSI 04-1999 3 11.3 Reproducibility The absolute difference between two single test results, obtained using the same method on identical test material in different laboratories with different operators using different equipment, will in not more than 5% of cases exc
40、eed the reproducibility limit R given by the equation: R = 0,138 % + 0,004 6 where 12 Test report The test report shall specify: all information necessary for the complete identification of the sample; the sampling method used, if known; the test method used, with reference to this International Sta
41、ndard; all operating details not specified in this International Standard, or regarded as optional, together with details of any incidents which may have influenced the test result(s); the test result(s) obtained; or if the repeatability has been checked, the final quoted result obtained. R is the r
42、eproducibility limit, as a percentage; is the mean of both results, as a percentage. w wBS4401-1:1998 4 BSI 04-1999 Annex A (informative) Bibliography 1 ISO 3100-1:1991, Meat and meat products Sampling and preparation of test samples Part1:Sampling. 2 ISO 5725:1986, Precision of test methods Determi
43、nation of repeatability and reproducibility for a standard test method by inter-laboratory tests. 3 ISO 5725-1:1994, Accuracy (trueness and precision) of measurement methods and results Part1:General principles and definitions. 4 ISO 5725-2:1994, Accuracy (trueness and precision) of measurement meth
44、ods and results Part 2: Basic method for the determination of repeatability and reproducibility of a standard measurement method. 5 Method No 23 (1991), Moisture and Ash:Gravimetric Determination in Meat and Meat Products. Nordic Committee on Food Analysis (NMKL), Espoo, Finland (in English and Scan
45、dinavian). (UDC 637.5). 6 Kolar, K. Gravimetric Determination of Moisture and Ash in Meat and Meat Products: NMKL Interlaboratory Study. J. AOAC, 75, 1992, pp. 1016-1022.blankBS 4401-1: 1998 ISO 936:1998 BSI 389 Chiswick High Road London W4 4AL BSIBritishStandardsInstitution BSI is the independent n
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