BS 770-1-1986 Methods for chemical analysis of cheese - General introduction《奶酪的化学分析法 一般介绍》.pdf

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1、BRITISH STANDARD CONFIRMED FEBRUARY1999 BS770-1:1986 Methods for Chemical analysis of cheese Part1: General introduction UDC 637.3.074BS770-1:1986 This BritishStandard, having been prepared under the directionof the Dairying Standards Committee, waspublished under the authorityofthe Board of BSIandc

2、omes into effect on 28 February1986 BSI 01-2000 First published January1938 First revision May1952 Second revision October1963 First Part revision February1976 Second Part revision February1986 The following BSI references relate to the work on this standard: Committee reference DAC/3 Draft for comm

3、ent 85/51848 DC ISBN 0 580 15052 6 Committees responsible for this BritishStandard The preparation of this BritishStandard was entrusted by the Dairying Standards Committee(DAC/-) to Technical Committee DAC/3, upon which the following bodies were represented: AFRC Food Research Institute, Reading As

4、sociation of British Preserved Milk Manufacturers Association of Public Analysts Association of Public Analysts of Scotland Creamery Proprietors Association Dairy Trade Federation Department of Trade and Industry(Laboratory of the Government Chemist) Ice Cream Alliance Limited Intervention Board for

5、 Agricultural Produce Joint Committee of the Milk Marketing Board and the Dairy Trade Federation Milk Marketing Board Milk Marketing Board for Northern Ireland Ministry of Agriculture, Fisheries and Food Royal Association of British Dairy Farmers Royal Society of Chemistry Society of Chemical Indust

6、ry Society of Dairy Technology University of Reading Amendments issued since publication Amd. No. Date of issue CommentsBS770-1:1986 BSI 01-2000 i Contents Page Committees responsible Inside front cover Foreword ii 1 Scope 1 2 Determinations supplementary to those in BS770 1 3 Sampling 1 4 Preparati

7、on of sample 1 5 Reagents 1 6 Rounding of numbers 1 7 Test reports 1 Publications referred to Inside back coverBS770-1:1986 ii BSI 01-2000 Foreword This Part of BS770 has been prepared under the direction of the Dairying Standards Committee. It supersedes BS770-1:1976 which is withdrawn. BS770 was f

8、irst published in1938 and revised in1952 and1963. Later it was decided to revise the standard in Parts to make easier the continuing task of implementing, in the form of BritishStandards, relevant methods prepared by subcommittee5, Milk and milk products, of Technical Committee34, Agricultural food

9、products, of the International Organization for Standardization. The first Parts of the multi-part revision were published in1976, and it is expected that the task of replacing the previous edition will be complete in1986, with the publication of Part8. When that Part is published, BS770:1963 will b

10、e withdrawn. A list of Parts of BS770 published or in preparation is given below. The methods in this revision have been aligned as far as possible with the corresponding ISOmethods and attention is drawn to this in the appropriate Parts. Part1: General introduction; Part2: Determination of water co

11、ntent(reference and routine methods); Part3: Determination of fat content(reference method); Part4: Determination of chloride content. Potentiometric titration method; Part5: Determination of pH value; Part6: Determination of total phosphorus content. Molecular absorption spectrometric method; Part7

12、: Determination of citric acid content(reference method); Part8: Determination of nitrogen content(reference method) 1) ; Part9: Determination of nitrate and nitrates content. Cadmium reduction and photometry method; Part10: Determination of total solids content(reference method). A British Standard

13、 does not 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

14、inside front cover, pagesi andii, pages1 and2, 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. 1) In preparation.BS770-1:1986 BSI 01-2000 1 1

15、Scope This Part of BS770 gives general instructions which need to be read in conjunction with each of the test methods described in other Parts(published separately). NOTE 1The method of preparation of the sample is a more detailed version of the method described in various International Standards o

16、n the analysis of cheese(e.g.ISO2962). NOTE 2The titles of the publications referred to in this standard are listed on the inside back cover. 2 Determinations supplementary to those inBS770 Reference should be made to the following methods in respect of these determinations. Determination of fat(Ger

17、ber method): BS696-1 and BS696-2 Estimation and differentiation of nisin in processed cheese: BS4020 Detection of foreign fats: a) vegetable fat(phytosteryl acetate method): BS5475-1; b) vegetable fat(GLC method of sterols): BS5475-2. 3 Sampling Carry out the sampling in accordance with the methods

18、described for cheese in BS809. 4 Preparation of sample 2) 4.1 Before the analysis, remove any inedible surface layer of the cheese in such a way as to obtain a sample representative of the cheese as it is usually consumed. 4.2 Comminute the sample either by means of an appropriate device, e.g.a suit

19、able grater or mortar and pestle, or by cutting it into small pieces and then quickly mix the resulting mass. If necessary, repeat the operation. Clean the device after each sample. If the sample cannot be so comminuted, mix it thoroughly by intensive kneading. If there is any visible evidence of se

20、paration of moisture or fat, an attempt should be made to reincorporate these into the prepared sample. In such cases the results of analysis may be unreliable and an appropriate note should be made in the test report. 4.3 Immediately transfer the prepared sample to an airtight container of minimum

21、size. Carry out the analysis as soon as possible, preferably on the same day as sample preparation. If delay is unavoidable, ensure that the sample is stored in such a way that loss of moisture from the cheese is prevented. 5 Reagents Unless otherwise stated, use reagents which are of recognized rea

22、gent grade and, wherever the use of water is required, use distilled or demineralized water complying with the requirements of BS3978. 6 Rounding of numbers In the various Parts of BS770, use the method of rounding numbers specified in BS1957. NOTEFor example, if95.14,95.15,95.25 and95.16 are to be

23、rounded to the nearest0.1, the rounded numbers are95.1,95.2,95.2, and95.2 respectively, i.e.where5 occurs in the second decimal place, the rounding is to the nearest even number in the first decimal place. 7 Test reports Include the following in the test reports: a) result of each test carried out,

24、expressed in accordance with the clause headed “expression of result” in the appropriate Part of BS770; b) full reference to the method of teste.g.“Part2 (reference method) of BS770”; c) note of any special factor that may have affected the result; d) details of the sample identity. Copper content:

25、BS6394-1 Iron content: BS6394-2 Lead content: BS6394-3 a a In preparation. 2) The techniques to be used for each particular type of cheese are indicated in the individual international cheese standards being prepared under the FAO/WHO Code of Principles concerning milk and milk products.2 blankBS770

26、-1:1986 BSI 01-2000 Publications referred to BS696, Gerber method for the determination of fat in milk and milk products. BS696-1, Apparatus. BS696-2, Methods. BS809, Methods for sampling milk and milk products. BS1957, Presentation of numerical values(fineness of expression; rounding of numbers). B

27、S3978, Water for laboratory use. BS4020, Methods for the estimation and differentiation of nisin in processed cheese. BS5475, Methods for detection of foreign fats in dairy products. BS5475-1, Detection of vegetable fat by the phytosteryl acetate test. BS5475-2, Detection of vegetable fat by gas-liq

28、uid chromatography of sterols(reference method). BS6394, Trace elements in milk and milk products. BS6394-1, Method for the determination of copper content(reference method). BS6394-2, Method for the determination of iron content(reference method). BS6394-3, Method for the determination of lead cont

29、ent(reference method) 3) . ISO2962, Cheese and processed cheese products Determination of phosphorus content(Reference method). 3) In preparation.BS770-1:1986 BSI 389 Chiswick High Road London W4 4AL BSIBritishStandardsInstitution BSI is the independent national body responsible for preparing Britis

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