1、DRAFT FOR DEVELOPMENT DD ISO/TS 6090:2004 Milk and dried milk, buttermilk and buttermilk powder, whey and whey powder Detection of phosphatase activity ICS 67.100.01; 67.100.10 DD ISO/TS 6090:2004 This Draft for Development was published under the authority of the Standards Policy and Strategy Commi
2、ttee on 5 January 2005 BSI 5 January 2005 ISBN 0 580 45164 X National foreword This Draft for Development reproduces verbatim ISO/TS 6090:2004. This publication is not to be regarded as a British Standard. It is being issued in the Draft for Development Series of publications and is of a provisional
3、 nature because there was an urgent need to get it to market and insufficient time to go through the formal standards procedure. It should be applied on this provisional basis, so that information and experience of its practical application may be obtained. Comments arising from the use of this Draf
4、t for Development are requested so that UK experience can be reported to the international organization responsible for the Technical Specification. A review of this publication will be initiated not later than 3 years after its publication by the international organization so that a decision can be
5、 taken on its status at the end of its 3-year life. Notification of the start of the review period will be made in an announcement in the appropriate issue of Update Standards. According to the replies received by the end of the review period, the responsible BSI Committee will decide whether to sup
6、port the conversion into an international standard, to extend the life of the Technical Specification for another 3 years or to withdraw it. Comments should be sent in writing to the Secretary of BSI Technical Committee AW/5, Milk and milk products, at British Standards House, 389 Chiswick High Road
7、, London W4 4AL, giving the document reference and clause number and proposing, where possible, an appropriate revision of the text. A list of organizations represented on this committee can be obtained on request to its secretary. Cross-references The British Standards which implement international
8、 publications referred to in this document may be found in the BSI Catalogue under the section entitled “International Standards Correspondence Index”, or by using the “Search” facility of the BSI Electronic Catalogue or of British Standards Online. Summary of pages This document comprises a front c
9、over, an inside front cover, the ISO/TS title page, pages ii to v, a blank page, pages 1 to 9 and a back cover. The BSI copyright notice displayed in this document indicates when the document was last issued. Amendments issued since publication Amd. No. Date Comments Reference numbers ISO/TS 6090:20
10、04(E) IDF/RM 82:2004(E) OSI DI dnaF 4002TECHNICAL SPECIFICATION ISO/TS 6090 IDF/RM 82 First edition 2004-03-15 Milk and dried milk, buttermilk and buttermilk powder, whey and whey powder Detection of phosphatase activity Lait et lait sec, babeurre et babeurre en poudre, lactosrum et lactosrum en pou
11、dre Dtermination de lactivit phosphatasique DDISO/TS6090:2004IS/OTS :0906(4002)E ID/FMR :284002(E) DPlcsid Fremia ihTs PDF file may ctnoian emdebt dedyfepcaes. In ccaocnadrw eith Aebods licensilop gnic,y this file mairp eb ynted iv roweb detu slahl ton ide ebtlnu deess the typefaces whice era hml er
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17、002 F All irhgts seredevr iiiForeword 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 interest
18、ed in a subject 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 Co
19、mmission (IEC) on all matters of electrotechnical standardization. International Standards are drafted in accordance with the rules given in the ISO/IEC Directives, Part 2. The main task of technical committees is to prepare International Standards. Draft International Standards adopted by the techn
20、ical 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. In other circumstances, particularly when there is an urgent market requirement for such documents, a technical committee m
21、ay decide to publish other types of normative document: an ISO Publicly Available Specification (ISO/PAS) represents an agreement between technical experts in an ISO working group and is accepted for publication if it is approved by more than 50 % of the members of the parent committee casting a vot
22、e; an ISO Technical Specification (ISO/TS) represents an agreement between the members of a technical committee and is accepted for publication if it is approved by 2/3 of the members of the committee casting a vote. An ISO/PAS or ISO/TS is reviewed after three years in order to decide whether it wi
23、ll be confirmed for a further three years, revised to become an International Standard, or withdrawn. If the ISO/PAS or ISO/TS is confirmed, it is reviewed again after a further three years, at which time it must either be transformed into an International Standard or be withdrawn. ISO/TS 6090|IDF/R
24、M 82 was prepared by Technical Committee ISO/TC 34, Food products, Subcommittee SC 5, Milk and milk products, and the International Dairy Federation (IDF), in collaboration with AOAC International. It is being published jointly by ISO and IDF and separately by AOAC International. DDISO/TS6090:2004IS
25、/OTS :0906(4002)E ID/FMR :284002(E) iv I SO dna ID 4002 F All irhgts seredevrForeword IDF (the International Dairy Federation) is a worldwide federation of the dairy sector with a National Committee in every member country. Every National Committee has the right to be represented on the IDF Standing
26、 Committees carrying out the technical work. IDF collaborates with ISO and AOAC International in the development of standard methods of analysis and sampling for milk and milk products. The main task of technical committees is to prepare International Standards. Draft International Standards adopted
27、 by the Action Teams and Standing Committees are circulated to the National Committees for voting. Publication as an International Standard requires approval by at least 50 % of IDF National Committees casting a vote. In other circumstances, particularly when there is an urgent market requirement fo
28、r such documents, a Standing Committee may decide to publish an other type of normative document which is called by IDF: Reviewed method. Such a method represents an agreement between the members of a Standing Committee and is accepted for publication if it is approved by at least 50 % of the commit
29、tee members casting a vote. A Reviewed method is equal to an ISO/PAS or ISO/TS and will, therefore, also be published jointly under ISO conditions. ISO/TS 6090|IDF/RM 82 was prepared by Technical Committee ISO/TC 34, Food products, Subcommittee SC 5, Milk and milk products, and the International Dai
30、ry Federation (IDF), in collaboration with AOAC International. It is being published jointly by ISO and IDF and separately by AOAC International. All work was carried out by the Joint ISO/IDF/AOAC Action Team, Characterization of heat treatment, of the Standing Committee, Minor components and charac
31、terization of physical properties, under the aegis of its project leader, Mr E. Wolters (DK). DDISO/TS6090:2004IS/OTS :0906(4002)E ID/FMR :284002(E) I SO dna ID 4002 F All irhgts seredevr vIntroduction This Technical Specification specifies a method which is not affected by the presence of phenol an
32、d is of particular use where difficulties due to environmental contamination by traces of phenol can give false results by the method as specified in ISO 3356. It is possible to detect a mass fraction of 0,5 % raw milk in pasteurized milk by procedure A, and a mass fraction of 0,2 % raw reconstitute
33、d product in pasteurized reconstituted product by procedure B. The method is published as a Technical Specification rather than an International Standard since no interlaboratory trial of the method could be organized fulfilling the requirements of ISO 5725-1 and ISO 5725-2. DDISO/TS6090:2004blank 4
34、002:0906ST/OSIDDTEHCNICAL SPECFICIATNOI IS/OTS :0906(4002)E ID/FMR :284002(E)I SO dna ID 4002 F All irhgts seredevr 1Milk and dried milk, buttermilk and buttermilk powder, whey and whey powder Detection of phosphatase activity 1 Scope This Technical Specification specifies a screening method for the
35、 detection of the phosphatase activity in cows milk and dried milk, buttermilk and buttermilk powder, and whey and whey powder. Two alternative procedures (A and B) are given. Procedure A is the simpler as it does not include a clarification treatment and is especially suited for milk. Procedure B i
36、ncludes a clarification step which allows a more sensitive detection through which better quantitative results can be obtained, if desired. If either method is used for checking the proper pasteurization of these products or their raw materials, then further tests are necessary to ensure that the ph
37、osphatase activity is not due to either heat-stable microbial phosphatase (see 9.3.1) or reactivated phosphatase (see 9.3.2). NOTE A method using a patented proprietary reagent is described in Annex A. 2 Normative references The following referenced document is indispensable for the application of t
38、his document. For dated references, only the edition cited applies. For undated references, the latest edition of the referenced document (including any amendments) applies. ISO 3356, Milk and dried milk, buttermilk and buttermilk powder, whey and whey powder Determination of phosphatase activity (R
39、eference method) 1)3 Terms and definitions For the purposes of this document, the following terms and definitions apply. 3.1 phosphatase activity activity of the (undenatured) alkaline phosphatase determined by the procedures described in this Technical Specification NOTE The phosphatase activity is
40、 expressed as a negative or positive result, and/or “to be re-examined according to ISO 3356”. 1) Equivalent to IDF 63. DDISO/TS6090:2004IS/OTS :0906(4002)E ID/FMR :284002(E) 2 I SO dna ID 4002 F All irhgts seredevr4 Principle The sample of the liquid product or that of the reconstituted liquid prod
41、uct is diluted with a buffer substrate containing disodium p-nitrophenyl phosphate at pH 10,6 and incubated at 37 C for 2 h. The p-nitrophenol is liberated by hydrolysis under the influence of any active alkaline phosphatase present in the sample. Any liberated p-nitrophenol is detected directly (me
42、thod A) or after clarification (method B) by its yellow colour, either visually or spectrometrically. If a positive result is obtained, the sample is tested for the presence of heat-stable microbial phosphatase via pasteurization, or for the presence of reactivated phosphatase via a dilution of the
43、sample to which magnesium acetate solution is added to reactivate the phosphatase. Either method A or method B is used to detect their presence. 5 Reagents Use only reagents of recognized analytical grade and distilled water or water of at least equivalent purity, unless otherwise specified. 5.1 Sod
44、ium hydroxide solution, c(NaOH) = 0,5 mol/l or 0,1 mol/l. 5.2 Diethanolamine hydrochloride buffer solution, pH = 10,6. Dissolve 15,8 g of diethanolamine hydrochloride (C 2 H 5 O) 2 NH 2 Cl in water. Dilute to 1 000 ml with water. 5.3 Buffer substrate solution Dissolve 1,5 g of disodium p-nitrophenol
45、 phosphate or 1,3 g of dihydrogen p-nitrophenol phosphate in diethanolamine hydrochloride buffer solution (5.2). Dilute to 1 000 ml with the buffer solution. If stored in a refrigerator at 4 C or lower, the buffer substrate solution is stable for up to four weeks. If 0,1 % chloroform (CHCl 3 ) is ad
46、ded, the buffer substrate solution can be kept for three to four months at that temperature. Any instability is denoted by the formation of a yellow colour. The test is always carried out with reference to a boiled product control containing the same quantities of buffer substrate solution. It is re
47、commended, therefore, to prepare a new solution if the present gives a colour reading in excess of 10 g when read in a 25 mm cell in the comparator (6.3) using distilled water in the other 25 mm cell. 5.4 Precipitants 5.4.1 Zinc sulfate solution Dissolve 30 g of zinc sulfate heptahydrate (ZnSO 4 7H
48、2 O) in water. Dilute to 100 ml with water. 5.4.2 Potassium hexacyanoferrate(II) solution Dissolve 15 g potassium hexacyanoferrate(II) trihydrate (K 4 Fe(CN) 6 3H 2 O) in water. Dilute to 100 ml with water. 5.5 Magnesium acetate solution Dissolve 35,4 g of magnesium acetate Mg(C 2 H 3 O 2 ) 2 4H 2 O
49、 in 25 ml of water. Warm slightly to dissolve the magnesium acetate completely. Dilute to 100 ml with water. 5.6 Litmus paper DDISO/TS6090:2004IS/OTS :0906(4002)E ID/FMR :284002(E) I SO dna ID 4002 F All irhgts seredevr 36 Apparatus 6.1 Balance, capable of weighing to the nearest 0,1 g. 6.2 Water baths, capable of operating at 37 C 1 C, at 63 C 1 C, and of boiling. 6.3 Spectrometer, suitable for measuring absorbance at a wavelength of 405
