1、BRITISH STANDARDBS ISO9233-1:2007Cheese, cheese rind andprocessed cheese Determination ofnatamycin contentPart 1: Molecular absorptionspectrometric method for cheese rindICS 67.100.30 - : 007+A1:2012EN ISO13BS EN ISO 9233-1:2013ISBN 978 0 580 79330 1Amendments/corrigenda issued since publicationDate
2、 Comments30 November 2012 Implementation of ISO amendment 1:2012: Amended definition 2.3 and subclause 7.130 June 2013 This corrigendum renumbers BS ISO 9233-1:2007 +A1:2012 as BS EN ISO 9233-1:2013This British Standard was published under the authority of the Standards Policy and Strategy Committee
3、 on 31 March 2008 The British Standards Institution 2013. Published by BSI Standards Limited 2013National forewordThis British Standard is the UK implementation of EN ISO 9233-1:2013. It is identical to ISO 9233-1:2007+A1:2012. It supersedes BS ISO 9233-1:2007+A1:2012, which is withdrawn.The UK part
4、icipation 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 can be obtained on request to its secretary.The publication does not purport to include all the necessary provisions of a contract
5、. Users are responsible for its correct application.Compliance with a British Standard cannot confer immunity from legal obligations.EUROPEAN STANDARD NORME EUROPENNE EUROPISCHE NORM EN ISO 9233-1 May 2013 ICS 67.100.30 English Version Cheese, cheese rind and processed cheese - Determination of nata
6、mycin content - Part 1: Molecular absorption spectrometric method for cheese rind (ISO 9233-1:2007 including Amd 1:2012) Fromage, crote de fromage et fromages fondus - Dtermination de la teneur en natamycine - Partie 1: Mthode par spectromtrie dabsorption molculaire pour crote de fromage (ISO 9233-1
7、:2007, Amd 1:2012 inclus)Kse, Kserinde und Schmelzkse - Bestimmung des Natamycingehalts - Teil 1: Molekularabsorptionsspektrometrisches Verfahren fr Kserinde (ISO 9233-1:2007 einschlielich Amd 1:2012) This European Standard was approved by CEN on 16 May 2013. CEN members are bound to comply with the
8、 CEN/CENELEC Internal Regulations which stipulate the conditions for giving this European Standard the status of a national standard without any alteration. Up-to-date lists and bibliographical references concerning such national standards may be obtained on application to the CEN-CENELEC Management
9、 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 own language and notified to the CEN-CENELEC Management Centre has the same status a
10、s 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, Greece, Hungary, Iceland, Ireland, Italy, Latvia, Lithuania, Luxembourg, Malta, Ne
11、therlands, Norway, Poland, Portugal, Romania, Slovakia, Slovenia, Spain, Sweden, Switzerland, Turkey and United Kingdom. EUROPEAN COMMITTEE FOR STANDARDIZATION COMIT EUROPEN DE NORMALISATION EUROPISCHES KOMITEE FR NORMUNG Management Centre: Avenue Marnix 17, B-1000 Brussels 2013 CEN All rights of ex
12、ploitation in any form and by any means reserved worldwide for CEN national Members. Ref. No. EN ISO 9233-1:2013: Eii BS EN ISO 9233-1:2013EN ISO 9233-1:2013 (E)EN ISO 9233-1:2013 (E) 3 Foreword The text of ISO 9233-1:2007 including Amd 1:2012 has been prepared by Technical Committee ISO/TC 34 “Food
13、 products” of the International Organization for Standardization (ISO) and has been taken over as EN ISO 9233-1:2013 by 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
14、 of a national standard, either by publication of an identical text or by endorsement, at the latest by November 2013, and conflicting national standards shall be withdrawn at the latest by November 2013. Attention is drawn to the possibility that some of the elements of this document may be the sub
15、ject of patent rights. CEN and/or CENELEC shall not be held responsible for identifying any or all such patent rights. According to the CEN-CENELEC Internal Regulations, the national standards organizations of the following countries are bound to implement this European Standard: Austria, Belgium, B
16、ulgaria, Croatia, 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, Slovakia, Slovenia, Spain, Sweden, Switzerland,
17、 Turkey and the United Kingdom. Endorsement notice The text of ISO 9233-1:2007 including Amd 1:2012 has been approved by CEN as EN ISO 9233-1:2013 without any modification. ii iiiContents PageForeword ivForeword. v1Scope . 12Terms and definitions. 13Principle. 14Reagents25Apparatus 26Sampling 37Prep
18、aration of test sample. 37.1 Cheese rind . 37.2 Cheese interior 38Procedure 48.1 Test portion. 48.2 Preparation of test solution. 48.3 Determination 59Calculation and expression of results 69.1 Calculation of natamycin mass fraction. 69.2 Calculation of absorbance. 69.3 Calculation of surface-area-r
19、elated natamycin mass . 79.4 Correction of results. 79.5 Expression of results. 710 Precision 710.1 Interlaboratory tests. 710.2 Repeatability 810.3 Reproducibility 811 Test report.8Annex A (informative) Examples 9Annex B (informative) Results of interlaboratory trial 13Bibliography. 14BS ISO 9233-1
20、:2007IDF 140-1:2007BS ISO 9233-1:2007+A1:2012IDF 140-1:2007+A1:2012iiiContents PageForeword ivForeword. v1Scope . 12Terms and definitions. 13Principle. 14Reagents25Apparatus 26Sampling. 7Preparation of test sample. 37.1 Cheese rind . 37.2 Cheese interior. 38Procedure 48.1 Test portion. 48.2 Preparat
21、ion of test solution. 48.3 Determinati n. 59Calculation and expression of results 69.1 Calculation of natamycin mass fraction. 69.2 Calculation of absorbance. 69.3 Calculation of surface-area-related natamycin mass . 79.4 Correction of results.9.5 Expression of results.10 Precision 710.1 Interlabora
22、tory tests. 710.2 Repeatability.10.3 Reproducibility 811 Test report.8Annex A (informative) Examples 9Annex B (informative) Results of interlaboratory trial 13Bibliography. 14BS ISO 9233-1:2007IDF 140-1:2007BS ISO 9233-1:2007+A1:2012IDF 140-1:2007+A1:2012BS EN ISO 9233-1:2013ISO 9233-1:2007+A1:2012b
23、lankblank1Cheese, cheeserind and processed cheese Determination of natamycin content Part 1: Molecular absorption spectrometric method for cheese rind 1 Scope This part of ISO 9233|IDF 140 specifies a method for the determination in cheese rind of natamycin mass fraction of above 0,5 mg/kg and surfa
24、ce-area-related natamycin mass of above 0,03 mg/dm2. NOTE It is possible that the method may be suitable for detecting migration of natamycin into the cheese. 2 Terms and definitions For the purposes of this document, the following terms and definitions apply.2.1 natamycin content mass fraction of s
25、ubstances determined by the procedure specified in this part of ISO 9233|IDF 140 NOTE The natamycin content is expressed in milligrams per kilogram. 2.2 surface-area-related natamycin mass in cheese rindsurface-area-related mass of substances determined by the procedure specified in this part of ISO
26、 9233|IDF 140 NOTE The surface-area-related natamycin massis expressed in milligrams of natamycin per square decimetre ofcheese rind. 2.3 cheese rindouter layer of the cheese of thickness 5 mm, excluding the coating layer, if present. 3 Principle A known quantityof sample is extracted with methanol.
27、 The extract is diluted with water followed by cooling tobetween 15 C and 20 C to precipitate most of the fat, followed by filtration. The natamycin content orsurface-area-related natamycin mass is determined in the filtrate (after concentration, ifnecessary) bymolecular absorption spectrometry. BS
28、ISO 9233-1:2007IDF 140-1:2007BS ISO 9233-1:2007+A1:2012IDF 140-1:2007+A1:2012outer layer of the cheese, excluding the coating layer, if present.BS EN ISO 9233-1:2013ISO 9233-1:2007+A1:20122 4 ReagentsUse only reagents of recognized analytical grade, unless otherwise specified, and onlydistilled orde
29、mineralized water orwater of equivalent purity. 4.1 Methanol (CH3OH).4.2 Methanol, aqueous solution. Mix 2 volumes ofmethanol (4.1)with 1 volume of water.4.3Natamycin standard solutions. 4.3.1 Natamycin standard stock solution, of concentration 500 mg/l. Immediately before use, dissolve in methanol
30、(4.1) a quantityof a natamycin preparation of known natamycincontent, corresponding to 50 mg of pure natamycin (C33H47NO13), in a 100 ml one-mark volumetric flask (5.1).Make up to the mark with water and mix.4.3.2Natamycin standard working solution, of concentration 5 mg/l. Pipette 5,0 ml of natamyc
31、in standard stock solution (4.3.1) into a 50 ml one-mark volumetric flask (5.1). Diluteto the mark with aqueous methanol (4.2) and mix.Pipette 5,0 ml of the thus diluted solution into another 50 ml one-mark volumetric flask (5.1). Dilute to the markwith aqueous methanol (4.2) and mix. The concentrat
32、ion of this natamycin standard working solution is5 g/ml. This concentration shall be close to that of the test solution measured in 8.3.3. Adjust the standard working dilution by pipetting and diluting another quantity, if required. 5 Apparatus Usual laboratory equipment and, in particular, the fol
33、lowing. 5.1One-mark volumetric flasks, of capacities 50 ml and 100 ml. 5.2 Slicer or similar apparatus, capable of cutting cheese portions of thickness 5 mm and of width about30 mm (Figure A.1 shows an example). 5.3 Fine slicer, capable of cutting thin cheese slices of maximum thickness 1 mm (Figure
34、 A.2 shows anexample). 5.4 Grinder or blender. 5.5 Sharp knife, capable of cutting cheese slices into small pieces. 5.6 Magnetic stirrer or shaking machine. 5.7 Conical flasks, of capacities 100 ml and 200 ml, made of coloured glass and fitted with ground-glassstoppers.5.8 Syringes, disposable, of c
35、apacity10 ml. 5.9 Membranemicrofilters, of pore size 0,20 m and 0,45 m, resistant to attack by alcoholic solutions.BS ISO 9233-1:2007IDF 140-1:2007BS ISO 9233-1:2007+A1:2012IDF 140-1:2007+A1:2012BS EN ISO 9233-1:2013ISO 9233-1:2007+A1:20122 4 ReagentsUse only reagents of recognized analytical grade,
36、 unless otherwise specified, and onlydistilled ordemineralized water orwater of equivalent purity. 4.1 Methanol (CH3OH).4.2 Methanol, aqueous solution. Mix 2 volumes ofmethanol (4.1)with 1 volume of water.4.3Natamycin standard solutions. 4.3.1 Natamycin standard stock solution, of concentration 500
37、mg/l. Immediately before use, dissolve in methanol (4.1) a quantityof a natamycin preparation of known natamycincontent, corresponding to 50 mg of pure natamycin (C33H47NO13), in a 100 ml one-mark volumetric flask (5.1).Make up to the mark with water and mix.4.3.2Natamycin standard working solution,
38、 of concentration 5 mg/l. Pipette 5,0 ml of natamycin standard stock solution (4.3.1) into a 50 ml one-mark volumetric flask (5.1). Diluteto the mark with aqueous methanol (4.2) and mix.Pipette 5,0 ml of the thus diluted solution into another 50 ml one-mark volumetric flask (5.1). Dilute to the mark
39、with aqueous methanol (4.2) and mix. The concentration of this natamycin standard working solution is5 g/ml. This concentration shall be close to that of the test solution measured in 8.3.3. Adjust the standard working dilution by pipetting and diluting another quantity, if required. 5 Apparatus Usu
40、al laboratory equipment and, in particular, the following. 5.1One-mark volumetric flasks, of capacities 50 ml and 100 ml. 5.2 Slicer or similar apparatus, capable of cutting cheese portions of thickness 5 mm and of width about30 mm (Figure A.1 shows an example). 5.3 Fine slicer, capable of cutting t
41、hin cheese slices of maximum thickness 1 mm (Figure A.2 shows anexample). 5.4 Grinder or blender. 5.5 Sharp knife, capable of cutting cheese slices into small pieces. 5.6 Magnetic stirrer or shaking machine. 5.7 Conical flasks, of capacities 100 ml and 200 ml, made of coloured glass and fitted with
42、ground-glassstoppers.5.8 Syringes, disposable, of capacity10 ml. 5.9 Membranemicrofilters, of pore size 0,20 m and 0,45 m, resistant to attack by alcoholic solutions.BS ISO 9233-1:2007IDF 140-1:2007BS ISO 9233-1:2007+A1:2012IDF 140-1:2007+A1:201235.10 Folded paper filters, fast speed, of diameter 15
43、0 mm e.g. S and S, No. 595 1/21). 5.11 Funnel, of diameter approximately 70 mm. 5.12 Freezer, capable of freezing at a temperature of between 15 C and 20 C. 5.13 Extractioncartridges, to concentrate the filtered extract, if necessary e.g. Sep-pack C181)orWatersNo. 519101). 5.14 Spectrometer, suitabl
44、e for recording an ultraviolet (UV) spectrum between 300 nm and 340 nm,equipped with cells of optical pathlength 10 mm and a recorder. 5.15 Sample jar, of suitable capacity.6 Sampling A representative sample should have been sent to the laboratory. It should not have been damaged orchanged during tr
45、ansport or storage. Sampling is not part of the method specified in this part of ISO 9233|IDF140. A recommended samplingmethod 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.7 Preparation of test sample 7.1 Cheese rind
46、If necessary, cut the test sample into sectors or smaller portions so that the width of the cheese rind is not more than about 30 mm. Using the slicer (5.2), remove the whole rind from all obtained sectors orportions byslicing off a maximum thickness of 5 mm.From the rind obtained, cut, with a sharp
47、 knife (5.5),a rectangular piece of area between 2 dm2and 4dm2. Determine its surface area, in square decimetres, and its mass, in kilograms.Grind (5.4) carefully the whole rind, including the weighed and measured piece, and mix thoroughly.Immediately transfer a quantity of the sample thus prepared
48、to a sample jar (5.15). After preparing each test sample, clean all tools that have been in contact with the sample with hot water andthen with methanol (4.1). Dry all tools thoroughly, e.g. by using a stream of compressed air.7.2 Cheese interiorAfter removing the rind (7.1), use the fine slicer (5.
49、3) to remove a slice of maximum thickness 1 mm from the whole of the outer section of the test sample. Cut all cheese slices into small pieces of about 50 mm2and mix thoroughly. Immediately transfer a quantityofthe sample thus prepared to a sample jar (5.15). 1) Example of a suitable product available commercially. This information is given for the convenience of users of thispart of ISO 9233|IDF 140 and does n
