1、BSI Standards PublicationWB11885_BSI_StandardCovs_2013_AW.indd 1 15/05/2013 15:06Cheese, cheese rind and processed cheese - Determination of natamycin contentPart 1: Molecular absorption spectrometric method for cheese rindBS EN ISO 92331:2018National forewordThis British Standard is the UK implemen
2、tation of EN ISO 92331:2018. It is identical to ISO 92331:2018. It supersedes BS EN ISO 92331:2013, which is withdrawn.The UK participation in its preparation was entrusted to Technical Committee AW/5, Chemical analysis of milk and milk products.A list of organizations represented on this committee
3、can be obtained on request to its secretary.This publication does not purport to include all the necessary provisions of a contract. Users are responsible for its correct application. The British Standards Institution 2018 Published by BSI Standards Limited 2018ISBN 978 0 580 51671 9ICS 67.100.30Com
4、pliance with a British Standard cannot confer immunity from legal obligations.This British Standard was published under the authority of the Standards Policy and Strategy Committee on 31 May 2018.Amendments/corrigenda issued since publicationDate Text affectedBRITISH STANDARDBS EN ISO 92331:2018EURO
5、PEAN STANDARDNORME EUROPENNEEUROPISCHE NORMEN ISO 9233-1May 2018ICS 67.100.30 Supersedes EN ISO 92331:2013EUROPEAN COMMITTEE FOR STANDARDIZATIONCOMIT EUROPEN DE NORMALISATIONEUROPISCHES KOMITEE FR NORMUNGCEN-CENELEC Management Centre: Avenue Marnix 17, B-1000 Brussels 2018 CEN Ref. No. EN ISO 92331:
6、2018: EAll rights of exploitation in any form and by any means reserved worldwide for CEN national MembersCheese, cheese rind and processed cheese Determination of natamycin content Part 1: Molecular absorption spectrometric method for cheese rind (ISO 92331:2018)Fromage, crote de fromage et fromage
7、s fondus Dtermination de la teneur en natamycine Partie 1: Mthode par spectromtrie dabsorption molculaire pour crote de fromage (ISO 92331:2018)Kse, Kserinde und Schmelzkse Bestimmung des Natamycingehalts Teil 1: Molekularabsorptionsspektrometrisches Verfahren fr Kserinde (ISO 92331:2018)This Europe
8、an Standard was approved by CEN on 4 April 2018.CEN members are bound to comply with the CEN/CENELEC Internal Regulations which stipulate the conditions for giving this European Standard the status of a national standard without any alteration. Uptodate lists and bibliographical references concernin
9、g such national standards may be obtained on application to the CENCENELEC Management Centre or to any CEN member.This European Standard exists in three official versions (English, French, German). A version in any other language made by translation under the responsibility of a CEN member into its
10、own language and notified to the CEN-CENELEC Management Centre has the same status as the official versions.CEN members are the national standards bodies of Austria, Belgium, Bulgaria, Croatia, Cyprus, Czech Republic, Denmark, Estonia, Finland, Former Yugoslav Republic of Macedonia, France, Germany,
11、 Greece, Hungary, Iceland, Ireland, Italy, Latvia, Lithuania, Luxembourg, Malta, Netherlands, Norway, Poland, Portugal, Romania, Serbia, Slovakia, Slovenia, Spain, Sweden, Switzerland, Turkey and United Kingdom.English VersionEN ISO 9233-1:2018 (E)European forewordThis document (EN ISO 92331:2018) h
12、as been prepared by Technical Committee ISO/TC 34 “Food products” in collaboration with Technical Committee CEN/TC 302 “Milk and milk products Methods of sampling and analysis” the secretariat of which is held by NEN.This European Standard shall be given the status of a national standard, either by
13、publication of an identical text or by endorsement, at the latest by November 2018, and conflicting national standards shall be withdrawn at the latest by November 2018.Attention is drawn to the possibility that some of the elements of this document may be the subject of patent rights. CEN shall not
14、 be held responsible for identifying any or all such patent rights.This document supersedes EN ISO 92331:2013.According to the CENCENELEC Internal Regulations, the national standards organizations of the following countries are bound to implement this European Standard: Austria, Belgium, Bulgaria, C
15、roatia, Cyprus, Czech Republic, Denmark, Estonia, Finland, Former Yugoslav Republic of Macedonia, France, Germany, Greece, Hungary, Iceland, Ireland, Italy, Latvia, Lithuania, Luxembourg, Malta, Netherlands, Norway, Poland, Portugal, Romania, Serbia, Slovakia, Slovenia, Spain, Sweden, Switzerland, T
16、urkey and the United Kingdom.Endorsement noticeThe text of ISO 9233-1:2018 has been approved by CEN as EN ISO 9233-1:2018 without any modification.2BS EN ISO 92331:2018ISO 9233-1:2018Foreword iv1 Scope . 12 Normative references 13 Terms and definitions . 14 Principle 15 Reagents 26 Apparatus . 27 Sa
17、mpling 38 Preparation of test sample . 38.1 Cheese rind . 38.2 Cheese interior 39 Procedure. 49.1 Test portion 49.1.1 Cheese rind . 49.1.2 Cheese interior 49.2 Preparation of test solution . 49.2.1 Cheese rind . 49.2.2 Cheese interior 49.3 Determination . 59.3.1 Determination and detection limits 59
18、.3.2 UV absorbance of natamycin standard working solution 59.3.3 Test solution. 59.3.4 Low natamycin content 510 Calculation and expression of results . 610.1 Calculation of natamycin mass fraction . 610.2 Calculation of absorbance . 610.3 Calculation of surfacearearelated natamycin mass . 710.4 Cor
19、rection of results . 710.5 Expression of results 711 Precision . 711.1 Interlaboratory tests 711.2 Repeatability . 711.3 Reproducibility . 812 Test report . 8Annex A (informative) Examples 9Annex B (informative) Results of interlaboratory trial 13Bibliography .14 ISO 2018 All rights reserved iiiCont
20、ents PageBS EN ISO 92331:2018ISO 9233-1:2018ForewordISO (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
21、 body interested in a subject for which a technical committee has been established has the right to be represented on that committee. International organizations, governmental and nongovernmental, in liaison with ISO, also take part in the work. ISO collaborates closely with the International Electr
22、otechnical Commission (IEC) on all matters of electrotechnical standardization. The procedures used to develop this document and those intended for its further maintenance are described in the ISO/IEC Directives, Part 1. In particular the different approval criteria needed for the different types of
23、 ISO documents should be noted. This document was drafted in accordance with the editorial rules of the ISO/IEC Directives, Part 2 (see www.iso.org/directives).Attention is drawn to the possibility that some of the elements of this document may be the subject of patent rights. ISO shall not be held
24、responsible for identifying any or all such patent rights. Details of any patent rights identified during the development of the document will be in the Introduction and/or on the ISO list of patent declarations received (see www.iso.org/patents).Any trade name used in this document is information g
25、iven for the convenience of users and does not constitute an endorsement. For an explanation on the voluntary nature of standards, the meaning of ISO specific terms and expressions related to conformity assessment, as well as information about ISOs adherence to the World Trade Organization (WTO) pri
26、nciples in the Technical Barriers to Trade (TBT) see the following URL: www.iso.org/iso/foreword.html.This document was prepared by Technical Committee ISO/TC 34, Food products, Subcommittee SC 5, Milk and milk products and the International Dairy Federation (IDF). It is being published jointly by I
27、SO and IDF.This second edition cancels and replaces the first edition (ISO 9233-1 | IDF 140-1:2007), of which it constitutes a minor revision to incorporate the amendment ISO 92331:2007/Amd.1:2012.A list of all parts in the ISO 9233 | IDF 140 series can be found on the ISO website.iv ISO 2018 All ri
28、ghts reservedBS EN ISO 92331:2018ISO 9233-1:2018IDF (the International Dairy Federation) is a non-profit private sector organization representing the interests of various stakeholders in dairying at the global level. IDF members are organized in National Committees, which are national associations c
29、omposed of representatives of dairyrelated national interest groups including dairy farmers, dairy processing industry, dairy suppliers, academics and governments/food control authorities. ISO and IDF collaborate closely on all matters of standardization relating to methods of analysis and sampling
30、for milk and milk products. Since 2001, ISO and IDF jointly publish their International Standards using the logos and reference numbers of both organizations.Attention is drawn to the possibility that some of the elements of this document may be the subject of patent rights. IDF shall not be held re
31、sponsible for identifying any or all such patent rights. Details of any patent rights identified during the development of the document will be in the Introduction and/or on the ISO list of patent declarations received (see www.iso.org/patents).Any trade name used in this document is information giv
32、en for the convenience of users and does not constitute an endorsement.This document was prepared by the IDF Standing Committee on Analytical methods for additives and contaminants and ISO Technical Committee ISO/TC 34, Food products, Subcommittee SC 5, Milk and milk products. It is being published
33、jointly by ISO and IDF.The work was carried out by the Joint ISO/IDF Action Team on Selected food additives and vitamins of the Standing Committee on Analytical methods for additives and contaminants under the aegis of its project leader, Mr. M. Carl (DE). ISO 2018 All rights reserved vBS EN ISO 923
34、31:2018This page deliberately left blankCheese, cheese rind and processed cheese - Determination of natamycin content Part 1: Molecular absorption spectrometric method for cheese rind1 ScopeThis document specifies a method for the determination in cheese rind of natamycin mass fraction of above 0,5
35、mg/kg and surfacearearelated natamycin mass of above 0,03 mg/dm2.NOTE It is possible that the method is suitable for detecting migration of natamycin into the cheese.2 Normative referencesThere are no normative references in this document.3 Terms and definitionsFor the purposes of this document, the
36、 following terms and definitions apply.ISO and IEC maintain terminological databases for use in standardization at the following addresses: IEC Electropedia: available at http:/www.electropedia.org/ ISO Online browsing platform: available at https:/www.iso.org/obp3.1natamycin contentmass fraction of
37、 substances determined by the procedure specified in this documentNote 1 to entry: The natamycin content is expressed in milligrams per kilogram.3.2surface-area-related natamycin mass in cheese rindsurface-area-related mass of substances determined by the procedure specified in this documentNote 1 t
38、o entry: The surfacearearelated natamycin mass is expressed in milligrams of natamycin per square decimetre of cheese rind.3.3cheese rindouter layer of the cheese, excluding the coating layer, if present4 PrincipleA known quantity of sample is extracted with methanol. The extract is diluted with wat
39、er followed by cooling to between 15 C and 20 C to precipitate most of the fat, followed by filtration. The natamycin content or surface-area-related natamycin mass is determined in the filtrate (after concentration, if necessary) by molecular absorption spectrometry.INTERNATIONAL STANDARDISO 9233-1
40、:2018(E) ISO and IDF 2018 All rights reserved 1BS EN ISO 92331:2018ISO 9233-1:2018(E)5 ReagentsUse only reagents of recognized analytical grade, unless otherwise specified, and only distilled or demineralized water or water of equivalent purity.5.1 Methanol (CH3OH).5.2 Methanol, aqueous solution.Mix
41、 two volumes of methanol (5.1) with one volume of water.5.3 Natamycin standard stock solution, of concentration 500 mg/l.Immediately before use, dissolve in methanol (5.1) a quantity of a natamycin preparation of known natamycin content, corresponding to 50 mg of pure natamycin (C33H47NO13), in a 10
42、0 ml onemark volumetric flask (6.1). Make up to the mark with water and mix.5.4 Natamycin standard working solution, of concentration 5 mg/l.Pipette 5,0 ml of natamycin standard stock solution (5.3) into a 50 ml one-mark volumetric flask (6.1). Dilute to the mark with aqueous methanol (5.2) and mix.
43、Pipette 5,0 ml of the thus diluted solution into another 50 ml one-mark volumetric flask (6.1). Dilute to the mark with aqueous methanol (5.2) and mix. The concentration of this natamycin standard working solution is 5 g/ml.This concentration shall be close to that of the test solution measured in 9
44、.3.3. Adjust the standard working dilution by pipetting and diluting another quantity, if required.6 ApparatusUsual laboratory equipment and, in particular, the following.6.1 One-mark volumetric flasks, of capacities 50 ml and 100 ml.6.2 Slicer or similar apparatus, capable of cutting cheese portion
45、s of thickness 5 mm and of width about 30 mm (Figure A.1 shows an example).6.3 Fine slicer, capable of cutting thin cheese slices of maximum thickness 1 mm (Figure A.2 shows an example).6.4 Grinder or blender.6.5 Sharp knife, capable of cutting cheese slices into small pieces.6.6 Magnetic stirrer or
46、 shaking machine.6.7 Conical flasks, of capacities 100 ml and 200 ml, made of coloured glass and fitted with ground-glass stoppers.6.8 Syringes, disposable, of capacity 10 ml.6.9 Membrane microfilters, of pore size 0,20 m and 0,45 m, resistant to attack by alcoholic solutions.2 ISO and IDF 2018 All
47、rights reservedBS EN ISO 92331:2018ISO 9233-1:2018(E)6.10 Folded paper filters, fast speed, of diameter 150 mm (e.g. S and S, No. 595 1/21).6.11 Funnel, of diameter approximately 70 mm.6.12 Freezer, capable of freezing at a temperature of between 15 C and 20 C.6.13 Extraction cartridges, to concentr
48、ate the filtered extract, if necessary (e.g. Sep-pack C181)or Waters No. 5191011).6.14 Spectrometer, suitable for recording an ultraviolet (UV) spectrum between 300 nm and 340 nm, equipped with cells of optical path length 10 mm and a recorder.6.15 Sample jar, of suitable capacity.7 SamplingA repres
49、entative sample should be sent to the laboratory. It should not be damaged or changed during transport or storage.Sampling is not part of the method specified in this document. A recommended sampling method is given in ISO 707 | IDF 50.The laboratory sample shall be a whole cheese, or a segment of a cheese representative of the whole.8 Preparation of test sample8.1 Cheese rindIf necessary, cut the test sample into sectors or smaller portions so that the width of the cheese rind is not more
