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1、BS EN 137512002 Foodstuffs -Detection of irradiated food using photostimulated luminescenceBS EN BRITISH STANDARD 13751:2002 Foodstuffs -Detection of irradiated food using photostimulated luminescence The European Standard EN 13751:2002 has the status of a British Standard ICs 671.050 NO COPYING WIT
2、HOUT BSI PERMISSION EXCEPT AS PERMITTED BY COPYRIGHT LAW British Standards CPNroopt v ryfeiodrpireg rRodhd teb uEsycau tIlrieHoSnp e ouarn nnd Cetrow lmiocrmeknintstgee pw efiotrhrm SCittEaeNndd wairtdhiozuat iloicne nse from IHS-,-,-BS EN13751:2002 National foreword This British Standard is the off
3、icial English language version of EN 13751:ZOOZ. The UK participation in its preparation was entrusted to Technical Committee Awl-13, Horizontal analysis, which has the responsibility to: - aid enquirers to understand the text; - present to the responsible internationalEuropean committee any enquiri
4、es on the interpretation, or proposals for change, and keep the UK interests 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 Brit
5、ish Standards which implement international or European 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 Onlin
6、e. This publication does not purport to include all the necessary provisions of a contract. Users are responsible for its correct application. Compliance with a British Standard does not of itselfconfer immunity from legal obligations. This British Standard, having Summary of pages been prepared und
7、er the This document comprises a front cover, an inside front cover, the EN title page, direction of the Consumer pages 2 to 11 and a back cover. Products and Services Sector Policy and Strategy Committee, The BSI copyright date displayed in this document indicates when the was published under the d
8、ocument was last issued. authority of the Standards Policy and Strategy Committee on 15 October 2002 Amd. No. Date Comments O BSI 15 October 2002 ISBN O 580 40587 7 CPNroopt v ryfeiodrpireg rRodhd teb uEsycau tIlrieHoSnp e ouarn nnd Cetrow lmiocrmeknintstgee pw efiotrhrm SCittEaeNndd wairtdhiozuat i
9、loicne nse from IHS-,-,-EUROPEAN STANDARD EN 13751 NORME EUROP?ENNE EUROP?ISCHE NORM September 2002 ICs 67.050 English version Foodstuffs - Detection of irradiated food using photostimulated luminescence Produits alimentaires - Dtection daliments Lebensmittel - Nachweis von bestrahlten Lebensmitteln
10、 mit ioniss par Photostimulierterphotoluminescence Lumineszenz This European Standard was approved by CEN on 5 August 2002. CEN members are bound to comply with the CENKENELEC Internal Regulations which stipulate the conditions for giving this European Standard the status of a national standard with
11、out any alteration. Up-todate lists and bibliographicalr eferences concerning such national standards may be obtained on application to the 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
12、 by translation under the responsibility of a CEN member into its own language and notified to the Management Centre has the same status as the official versions. CEN members are the national standards bodies of Austria, Belgium, Czech Republic, Denmark, Finland, France, Germany, Greece, Iceland, Ir
13、eland, Italy, Luxembourg, Malta, Netherlands, Noway, Portugal, Spain, Sweden, Switzerland and United Kingdom. EUROPEAN COMMITTEE FOR STANDARDIZATION COMITE EUROPEEN DE NORMALISATION EUROP?ISCHES KOMITEE FOR NORMUNG Management Centre: rue de Stassart, 36 B-1050 Brussels O 2002 CEN All rights of explo
14、itation in any form and by any means reserved Ref. No. EN 13751:2002 E worldwide for CEN national Members. -,-,-CPNroopt v ryfeiodrpireg rRodhd teb uEsycau tIlrieHoSnp e ouarn nnd Cetrow lmiocrmeknintstgee pw efiotrhrm SCittEaeNndd wairtdhiozuat iloicne nse from IHSEN 13751: 2002 (E) Contents Page F
15、oreword. . 3 1 Scope . 3 2 Terms and definitions. . 3 3 Principle . 4 4 Reagents . 5 5 Apparatus . 5 6 Sampling technique . 6 7 Procedure . 6 8 Evaluation . 7 9 Limitations. . 9 10 Validation . 9 11 Test report . 10 Bibliography . 11 2 CPNroopt v ryfeiodrpireg rRodhd teb uEsycau tIlrieHoSnp e ouarn
16、nnd Cetrow lmiocrmeknintstgee pw efiotrhrm SCittEaeNndd wairtdhiozuat iloicne nse from IHS-,-,-EN 13751:2002 (E) Foreword This document EN 13751: 2002 has been prepared by Technical Committee CENTTC 275 ;Food analysis - Hori- zontal methods;, the secretariat of which is held by DIN. This European St
17、andard shall be given the status of a national standard, either by publication of an identical text or by endorsement, at the latest by March 2003, and conflicting national standards shall be withdrawn at the latest by March 2003. According to the CENCENELEC Internal Regulations, the national standa
18、rds organizations of the following coun- tries are bound to implement this European Standard: Austria, Belgium, Czech Republic, Denmark, Finland, France, Germany, Greece, Iceland, Ireland, Italy, Luxembourg, Malta, Netherlands, Norway, Portugal, Spain, Swe- den, Switzerland and the United Kingdom. 1
19、 Scope This European Standard specifies a method for the detection of irradiated foods using photostimulated lumines- cence (PSL). The technique described here comprises an initial measurement of PSL intensity which may be used for screening purposes, and a calibration method to determine the PSL se
20、nsitivity to assist classification. It is nec- essary to confirm a positive screening result using calibrated PSL or another standardised (e.g. EN 1784 to EN 1788) or validated method. The method has been successfully tested in interlaboratory trials using shellfish and herbs, spices and seasonings
21、l.F rom other studies it may be concluded that the method is applicable to a large variety of foods 2, 3, 4. 2 Terms and definitions For the purposes of this European Standard, the following terms and definitions apply. 2.1 photostimulated luminescence (PSL) radiation specific phenomenon resulting f
22、rom energy stored by trapped charge carriers. Release of this stored en- ergy by optical stimulation can result in a detectable luminescence signal. 2.2 PSL intensity amount of light detected during photostimulation, in photon count rate 2.3 screening PSL or initial PCL PSL intensity recorded from t
23、he sample as received or following preparation 2.4 calibrated PSL PSL intensity recorded from the test sample following irradiation to a known dose, after initial PSL measurement 2.5 thresholds values of PSL intensity used for classification. In screening mode, two thresholds, a lower threshold (TI)
24、 and an upper threshold (T2) are used to classify the sample 3 CPNroopt v ryfeiodrpireg rRodhd teb uEsycau tIlrieHoSnp e ouarn nnd Cetrow lmiocrmeknintstgee pw efiotrhrm SCittEaeNndd wairtdhiozuat iloicne nse from IHS-,-,-EN 13751:2002 (E) 2.6 negative PSL result PSL intensity below the lower thresh
25、old (less than TI) 2.7 intermediate PSL result PSL intensity between the upper and the lower threshold (greater than or equal to TI, less than or equal to T2) 2.8 positive PSL result PSL intensity above the upper threshold (greater than T2) 2.9 dark count photon count rate from the photomultiplier w
26、ith an empty chamber in the absence of stimulation 2.1 o light count photon count rate with a reference light source (e.g. 14C loaded scintillant, or equivalent) in the sample chamber 2.1 1 empty chamber run PSL intensity measured from an empty sample chamber to ensure absence of contamination of th
27、e chamber 3 Principle 3.1 General Mineral debris, typically silicates or bioinorganic materials such as calcite which originate from shells or exoskele- tons, or hydroxyapatite from bones or teeth, can be found on most foods. These materials store energy in charge carriers trapped at structural, int
28、erstitial or impurity sites, when exposed to ionising radiation. Excitation spectros- copy has shown that optical stimulation of minerals releases charge carriers 5, 6, 7.I t has subsequently been shown that the same spectra can be obtained from whole herb and spice samples and other foods using pho
29、tostimulation 2, 8, 9. PSL measurements do not destroy the sample, therefore whole samples, or other mixtures of organic and inorganic material, can be measured repeatedly. PSL signals, however, decrease if the same sample is measured repeatedly. The methodology comprises screening (initial) PSL mea
30、surements to establish the status of the sample (see 2.3) and an optional second measurement following a calibration radiation dose to determine the PSL sensitivity of the sample (see 2.4). 3.2 Screening PSL For screening (see 2.3) the signal levels are compared with two thresholds (see 2.5). The ma
31、jority of irradiated samples produce a strong signal above the upper threshold level. Signals below the lower threshold suggest that the sample has not been irradiated. Signal levels between the two thresholds, intermediate signals, show that fur- ther investigations are necessary. The use of thresh
32、olds produces an effective screening method which can also be backed up by calibration, by TL as described in EN 1788 or another validated method, e.g. 3, 4, 8. 3.3 Calibrated PSL For calibration, the sample is exposed to a defined radiation dose after the initial PSL measurement, and then re- measu
33、red. Irradiated samples show only a small increase in PSL after this radiation exposure, whereas unirradi- ated samples usually show a substantial increase in PSL signal after irradiation. 4 CPNroopt v ryfeiodrpireg rRodhd teb uEsycau tIlrieHoSnp e ouarn nnd Cetrow lmiocrmeknintstgee pw efiotrhrm SC
34、ittEaeNndd wairtdhiozuat iloicne nse from IHS-,-,-EN 13751:2002 (E) 4 Reagents 4.1 Aerosol silicone grease,e.g. Electrolube SC0200H) 4.2 Water,deionized 5 Apparatus 5.1 PSL cystem,e.g. SURRC PPSL Irradiated food screening system) lo, ll, 12, 13 comprising sample chamber, stimulation source, pulsed s
35、timulation and synchronised photon counting system. For instrumental set- up, see 7.4. NOTE For the interlaboratoryt ests, the SURRC PPSL system has been used. 5.2 Disposable Petri-dishes NOTE For the interlaboratoryt ests, 5 cm Petri-dishes have been used. 5.3 Radiation source,capable of irradiatin
36、g samples with a defined radiation dose before measurement of calibrated PSL. In the interlaboratory tests on shellfish and herbs, spices and their mixtures l, sources delivering Eo Co-rays have been employed at a fixed radiation dose of 1 kGy. Alternative sources may be used providing they have bee
37、n found satisfactory. NOTE Other fixed doses can be suitable. 5.4 -ource(optiona) 5.5 Laminar flow cabinet(optiona1) 5.6 Air duster(optiona1) 6 Sampling technique Whenever possible, the sample is taken from a light-protected position in the food consignment, since the PSL in- tensity decreases on ex
38、posure to light. Before analysis, samples should be protected against light exposure. Store them in the dark. 7 Procedure 7.1 General All dispensing and handling of samples should be carried out under subdued lighting whenever possible. Samples are dispensed into disposable Petri-dishes and introduc
39、ed to the system. ) Electrolube SC0200H and Scottish Universities Research and Reactor Center Pulsed Photostimulated Luminescence (SURRC PPSL) are examples of products available commercially. This information is given for the convenience of users of this standard and does not constitute an endorseme
40、nt of CEN of these products. Equivalent products may be used if they can be shown to lead to equivalent results. 5 CPNroopt v ryfeiodrpireg rRodhd teb uEsycau tIlrieHoSnp e ouarn nnd Cetrow lmiocrmeknintstgee pw efiotrhrm SCittEaeNndd wairtdhiozuat iloicne nse from IHS-,-,-EN 13751:2002 (E) Samples
41、should be handled with care to avoid cross-contamination during dispensing. It is recommended that samples are dispensed individually, under a laminar flow cabinet (5.5), and fresh tissue is placed on the bench for each sample. The Petri-dish should be covered with a lid to reduce the possibility of
42、 contamination. 7.2 Preparation of herb, spice and seasoning samples Samples are dispensed into clean Petri-dishes, in duplicate. If these test samples lead to inconsistent classifica- tions, a further four aliquots shall be dispensed and classification based on the highest two results. Some samples may require a minimum of preparation; e.g. vanilla pods may need to be cut to fit the dish and wrappings should be removed. Samples can either be dispensed in a thick layer within the Petri-dish or in a thin