1、BRITISH STANDARD BS EN ISO 7937:2004 Microbiology of food and animal feeding stuffs Horizontal method for the enumeration of Clostridium perfringens Colony-count technique The European Standard EN ISO 7937:2004 has the status of a British Standard ICS 07.100.30 BS EN ISO 7937:2004 This British Stand
2、ard was published under the authority of the Standards Policy and Strategy Committee on 25 August 2004 BSI 25 August 2004 ISBN 0 580 44349 3 National foreword This British Standard is the official English language version of EN ISO 7937:2004. It is identical with ISO 7937:2004. It supersedes BS EN 1
3、3401:1999 which is withdrawn. The UK participation in its preparation was entrusted to Technical Committee AW/9, Microbiology, which has the responsibility to: A list of organizations represented on this committee can be obtained on request to its secretary. Cross-references The British Standards wh
4、ich 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 Online. This public
5、ation 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 itself confer immunity from legal obligations. aid enquirers to understand the text; present to the responsible internationa
6、l/European committee any enquiries 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. Summary of pages This document comprises a front cover, an inside front cover, the EN ISO titl
7、e page, the EN ISO foreword page, the ISO title page, pages ii to v, a blank page, pages 1 to 16, an inside back cover 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 CommentsEUROPEAN
8、STANDARD NORMEEUROPENNE EUROPISCHENORM ENISO7937 August2004 ICS07.100.30 SupersedesEN13401:1999 Englishversion MicrobiologyoffoodandanimalfeedingstuffsHorizontal methodfortheenumerationofClostridiumperfringensColony counttechnique(ISO7937:2004) MicrobiologiedesalimentsMthodehorizontalepourle dnombre
9、mentdeClostridiumperfringensTechniquepar comptagedescolonies(ISO7937:2004) MikrobiologievonLebensmittelnundFuttermitteln HorizontalesVerfahrenzurZhlungvonClostridium perfringensKoloniezhlverfahren(ISO7937:2004) ThisEuropeanStandardwasapprovedbyCENon14August2004. CENmembersareboundtocomplywiththeCEN/
10、CENELECInternalRegulationswhichstipulatetheconditionsforgivingthisEurope an Standardthestatusofanationalstandardwithoutanyalteration.Uptodatelistsandbibliographicalreferencesconcernings uchnational standardsmaybeobtainedonapplicationtotheCentralSecretariatortoanyCENmember. ThisEuropeanStandardexists
11、inthreeofficialversions(English,French,German).Aversioninanyotherlanguagemadebytra nslation undertheresponsibilityofaCENmemberintoitsownlanguageandnotifiedtotheCentralSecretariathasthesamestatusast heofficial versions. CENmembersarethenationalstandardsbodiesofAustria,Belgium,Cyprus,CzechRepublic,Den
12、mark,Estonia,Finland,France, Germany,Greece,Hungary,Iceland,Ireland,Italy,Latvia,Lithuania,Luxembourg,Malta,Netherlands,Norway,Poland,Portugal, Slovakia, Slovenia,Spain,Sweden,SwitzerlandandUnitedKingdom. EUROPEANCOMMITTEEFORSTANDARDIZATION COMITEUROPENDENORMALISATION EUROPISCHESKOMITEEFRNORMUNG Man
13、agementCentre:ruedeStassart,36B1050Brussels 2004CEN Allrightsofexploitationinanyformandbyanymeansreserved worldwideforCENnationalMembers. Ref.No.ENISO7937:2004:E I NESO 97:7302( 40E) 2 Foreword This document (EN ISO 7937:2004) has been prepared by Technical Committee ISO/TC 34 “Agricultural food pro
14、ducts“ in collaboration with Technical Committee CEN/TC 275 “Food analysis - Horizontal methods“, the secretariat of which is held by DIN. This European Standard shall be given the status of a national standard, either by publication of an identical text or by endorsement, at the latest by February
15、2005, and conflicting national standards shall be withdrawn at the latest by February 2005. This document supersedes EN 13401:1999. According to the CEN/CENELEC Internal Regulations, the national standards organizations of the following countries are bound to implement this European Standard: Austri
16、a, Belgium, Cyprus, Czech Republic, Denmark, Estonia, Finland, France, Germany, Greece, Hungary, Iceland, Ireland, Italy, Latvia, Lithuania, Luxembourg, Malta, Netherlands, Norway, Poland, Portugal, Slovakia, Slovenia, Spain, Sweden, Switzerland and United Kingdom. Endorsement notice The text of ISO
17、 7937:2004 has been approved by CEN as EN ISO 7937:2004 without any modifications. ENISO7937:2004 Reference number ISO 7937:2004(E) OSI 4002INTERNATIONAL STANDARD ISO 7937 Third edition 2004-08-15 Microbiology of food and animal feeding stuffs Horizontal method for the enumeration of Clostridium per
18、fringens Colony-count technique Microbiologie des aliments Mthode horizontale pour le dnombrement de Clostridium perfringens Technique par comptage des colonies ENISO7937:2004IS:7397 O4002(E) DPlcsid Fremia ihTs PDF file may ctnoian emdebt dedyfepcaes. In ccaocnadrw eith Aebods licensilop gnic,y thi
19、s file mairp eb ynted iv roweb detu slahl ton ide ebtlnu deess the typefaces whice era hml era deddebicsnede to i dnanstlaled t noeh computfrep reormign tide ehtin.g In wodlnidaot gnhis file, trapise atpecc tiereht nser ehnopsiiblity fo not infriigngn Aebods licensilop gnic.y ehT ISO tneClar Secrtei
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21、u that the file is suitlbae fosu re yb ISO memdob rebeis. In tlnu ehikletneve y ttah lborp aem leratit gno it is f,dnuo plsaee inform ttneC ehlar Secrteiraat ta the serddaig sleb nevwo. ISO 4002 All irthgs erse.devr lnUeto sswrehise specified, on trap fo this lbupictaion maeb y cudorperro de tuilizi
22、 den yna form ro na ybm ynae,s lecetrinoc ro mecinahcal, inclidung tohpcoiypodna gn micrfoilm, wittuoh repmissii non writign from ietI rehSa Ot tsserdda eh ebolw or ISOs memreb i ydobn the cnuotrfo y ttseuqer ehe.r ISO cirypothg fofice saCe tsopale 65 eneG 1121-HC 2 av0 Tel. 4 + 10 947 22 1 11 xaF0
23、947 22 14 + 9 74 E-mail coirypthgiso.o gr We bwww.is.o gro Pulbisdehi n Switlrez dnaii ISO 4002 Allr ithgsr esedevrENISO7937:2004IS:7397 O4002(E) I SO 4002 All irthgs ersedevr iiiContents Page Foreword iv Introduction v 1 Scope 1 2 Normative references. 1 3 Terms and definitions. 2 4 Principle. 2 5
24、Diluent, culture media and reagents . 2 6 Apparatus and glassware. 7 7 Sampling 7 8 Preparation of test sample. 7 9 Procedure. 7 10 Expression of results 9 11 Test report 11 Annex A (informative) Results of interlaboratory test 12 Bibliography . 16 ENISO7937:2004ISO 7937:2004(E) iv I SO 4002 All irt
25、hgs ersedevrForeword 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 interested in a subject f
26、or 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 Commission (IEC) on
27、 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 technical committees a
28、re 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. 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
29、responsible for identifying any or all such patent rights. ISO 7937 was prepared by Technical Committee ISO/TC 34, Food products, Subcommittee SC 9, Microbiology. This third edition cancels and replaces the second edition (ISO 7937:1997, EN 13401:1999), which has been technically revised. ENISO7937:
30、2004IS:7397 O4002(E) I SO 4002 All irthgs ersedevr vIntroduction Because of the large variety of food and feed products, this horizontal method may not be appropriate in every detail for certain products. In this case, different methods that are specific to these products may be used if absolutely n
31、ecessary for justified technical reasons. Nevertheless, every attempt should be made to apply this horizontal method as far as possible. When this International Standard is next reviewed, account will be taken of all information then available regarding the extent to which this horizontal method has
32、 been followed and the reasons for deviations from this method in the case of particular products. The harmonization of test methods cannot be immediate and, for certain groups of products, International Standards and/or national standards may already exist that do not comply with this horizontal me
33、thod. It is hoped that when such standards are reviewed they will be changed to comply with this international Standard so that eventually the only remaining departures from this horizontal method will be those necessary for well-established technical reasons. ENISO7937:20044002:7397OSINEINTENRATION
34、AL TSANDADR IS:7397 O4002(E)I SO 4002 All irthgs ersedevr 1Microbiology of food and animal feeding stuffs Horizontal method for the enumeration of Clostridium perfringens Colony-count technique 1 Scope This International Standard describes a horizontal method for the enumeration of viable Clostridiu
35、m perfringens. It is applicable to products intended for human consumption and the feeding of animals, and environmental samples in the area of food production and food handling. 2 Normative references The following referenced documents are indispensable for the application of this document. For dat
36、ed references, only the edition cited applies. For undated references, the latest edition of the referenced document (including any amendments) applies. ISO 6887-1, Microbiology of food and animal feeding stuffs Preparation of test samples, initial suspension and decimal dilutions for microbiologica
37、l examination Part 1: General rules for the preparation of the initial suspension and decimal dilutions ISO 6887-2, Microbiology of food and animal feeding stuffs Preparation of test samples, initial suspension and decimal dilutions for microbiological examination Part 2: Specific rules for the prep
38、aration of meat and meat products ISO 6887-3, Microbiology of food and animal feeding stuffs Preparation of test samples, initial suspension and decimal dilutions for microbiological examination Part 3: Specific rules for the preparation of fish and fishery products ISO 6887-4, Microbiology of food
39、and animal feeding stuffs Preparation of test samples, initial suspension and decimal dilutions for microbiological examination Part 4: Specific rules for the preparation of products other than milk and milk products meat and meat products, and fish and fishery products ISO 7218, Microbiology of foo
40、d and animal feeding stuffs General rules for microbiological examinations ISO 8261, Milk and milk products General guidance for the preparation of test samples, initial suspensions and decimal dilutions for microbiological examination ISO/TS 11133-1, Microbiology of food and animal feeding stuffs G
41、uidelines on preparation and production of culture media Part 1 : General guidelines on quality assurance for the preparation of culture media in the laboratory ISO/TS 11133-2:2003, Microbiology of food and animal feeding stuffs Guidelines on preparation and production of culture media Part 2: Pract
42、ical guidelines on performance testing of culture media ENISO7937:2004IS:7397 O4002(E) 2 I SO 4002 All irthgs ersedevr3 Terms and definitions For the purposes of this document, the following terms and definitions apply. 3.1 Clostridium perfringens C. perfringens bacteria that form characteristic col
43、onies (black precipitate, caused by the reduction of sulfite to sulfide, which colours the colonies black) in the specified selective medium, and which give positive confirmatory reactions when the test is carried out by either of two techniques specified in this International Standard 3.2 enumerati
44、on of C. perfringens determination of the number of culturable and confirmed Clostridium perfringens bacteria per millilitre or per gram of sample when the test is carried out by the method specified in this International Standard 4 Principle 4.1 Petri dishes are inoculated with a specified quantity
45、 of the test sample if the initial product is liquid, or a specified quantity of the initial suspension in the case of other products. Further Petri dishes are inoculated, under the same conditions, using decimal dilutions of the test sample or of the initial suspension. A selective medium is added
46、(poured-plate technique) and then an overlay of the same medium. 4.2 The plates are incubated anaerobically at 37 C for 20 h 2 h. 4.3 The characteristic colonies are enumerated. 4.4 The numbers of characteristic colonies are confirmed and the number of C. perfringens per millilitre or per gram of sa
47、mple is calculated. 5 Diluent, culture media and reagents See ISO 7218, ISO/TS 11133-1 and ISO/TS 11133-2 for the preparation, production and performance testing of culture media. 5.1 Diluent See the relevant part of ISO 6887 or ISO 8261. 5.2 Sulfite-cycloserine agar (SC) NOTE This was originally de
48、signated “egg-yolk-free TSC” (see 1). ENISO7937:2004ISO 7937:2004(E) I SO 4002 All irthgs ersedevr 35.2.1 Base 5.2.1.1 Composition Enzymatic digest of protein 15,0 g Enzymatic digest of soya 5,0 g Yeast extract 5,0 g Disodium disulfite (Na 2 S 2 O 5 ), anhydrous 1,0 g Ammonium iron(III) citrate a1,0 g Agar 9,0 g to 18,0 g bWater 1 000 ml aThis reagent should contain at least 15 % (mass fraction) of iron. bDepending on the gel strength of the agar. 5.2.
