BS ISO BRITISH STANDARD 4831:2006 Microbiology of food and animal feeding stuffs Horizontal method for the detection and enumeration of coliforms Most probable number technique ICS 07.100.30 BSi NO COPYING WITHOUT BSI PERMISSION EXCEPT AS PERMITTED BY COPYRIGHT LAW British Standards BSIS04831:2006 National foreword This British Standard was published by BSI. It is the UK implementation of ISO 4831:2006.It supersedes BS 5763-3:1991 which is withdrawn. The UK participation in its preparation was entrusted to Technical Committee AW/9, Microbiology. A list of organizations represented on AW/9 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. Compliance with a British Standard cannot confer immunity from legal obligations. This British Standard was Amendmentsissuedsincepublication published under the authority of the Standards Policy and Date Amd. No. Comments Strategy Committee on 29 December 2006 BSI 2006 ISBN 0580 485056 BS ISO 4831:2006 ISO INTERNATIONAL STANDARD 4831 Third edition 2006-08-15 Microbiology of food and animal feeding stuffs Horizontal method for the detection andenumeration of coliforms Most probable number technique Microbiologiedes alimentsMethodehorizontalepourlarechercheet ledenombrementdescoliformes-Techniquedunombreleplus probable Referencenumber ISO 4831:2006(E) ii BS IS0 4831:2006 Foreword IsO (the International Organization for Standardization) is a worldwide federation of national standards bodies non-governmental, in liaison with isO, also take part in the work. iso collaborates closely with the InternationalElectrotechnicalCommission(lEC)onallmattersofelectrotechnicalstandardization The main task of technical committees is to prepare International Standards.Draft International Standards adopted by the technical committees are circulated to the member bodies for voting. Publication as an International Standard requires approval by at least 75% of the memberbodies casting a vote. rights. IsO shall not be held responsible for identifying any or all such patent rights. ISO 4831 was prepared by Technical Committee ISO/TC 34, Food products, Subcommittee SC 9, Microbiology. This third edition of ISO 4831 cancels and replaces ISO 4831:1991 and ISO5541-2:1986.Clauses4,9 and 10ofisO4831:1991havebeentechnicallyrevised.Themainchanges areasfollows the alternative procedure of incubation at 35 °C has been deleted; detection and enumeration of coliforms are covered (Clauses 4 and 9); description of the MPN and the CCT have been omitted (Clause 10) and reference is given to ISO 7218 that the validation of alternative methods based on ISO 4831:1991 is not affected by this revision i BS ISO 4831:2006 Introduction detail for certain products. In this case, different methods, which are specific to these products, may be used if absolutely necessary 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 this method in the case of particular products. Theharmonizationoftest methodscannotbeimmediate and,forcertaingroupsofproducts,International 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. of coliforms per gram or per mililitre of product to be detected. Moreover, since the definition of “coliforms" that product. A proportion of strains of the microorganisms described in other published texts as “coliforms" (including strains"). Therefore the method described in this International Standard will not detect all strains of the Citrobacter,Enterobacter,Klebsiella)(seeReference[2]), iv BSIS04831:2006 Microbiology of f