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Appendix B General Principles for the Establishment and Application of Microbiological Criteria for Woodsy These general principles are intended to guide, primarily, Codex com- mittees in the establishment and application of microbiological criteria, and to this end they contain definitions of mandatory and advisory criteria which relate specifically to the requirements of the Codex Alimentarius. They are also intended for application where microbiological criteria for foods are being developed. DEFINITION OF MICROBIOLOGICAL CRITERIA FOR FOODS A microbiological criterion as defined for Codex purposes, consists of: 1.1 a statement of the microorganisms and parasites of concern and/ or their toxins. For this purpose, microorganisms include bacteria, viruses, yeasts, and molds; 1.2 the analytical methods for their detection and quantification; 1.3 a plan defining the number of field samples to be taken, the size of the sample unit, and where and, if appropriate, when the samples are to be taken; 1.4 microbiological limits considered appropriate to the food; and 1.5 the number of sample units that should conform to these limits. 2. APPLICATION OF MICROBIOLOGICAL CRITERIA Microbiological criteria, as defined for Codex purposes, fall into two main categories: (See also Section 5 for interpretation) Appendix II, 17th Session, Committee on Food Hygiene, Codex Alimentarius. 366
APPENDIX B 367 2.1 Mandatory criterion 2.1.1 A microbiological starboard is a criterion contained in a Codex Alimentarius Standard. Wherever possible it should contain limits only for pathogenic microorganisms of public health signifi- cance in the food concerned. Limits for nonpathogenic microorgan- isms may be necessary and when these are included the provisions of paragraph 6.1 shall apply. A microbiological standard shall not be introduced de novo but shall be derived from microbiological end- product specifications which have accompanied Codes of Practice through the Codex Procedure and which have been extensively applied to the food. 2.2 Advisory criterion An advisory criterion is one of two types contained in Codes of Practice. 2.2.1 A microbiologicalend-product specification is intended to increase assurance that the provisions of hygienic significance in the Code have been met. It may include microorganisms which are not of direct public health significance. 2.2.2 A microbiological guideline is applied at the establishment at a specified point during or after processing to monitor hygiene. It is intended to guide the manufacturer and is not intended for official control purposes. It may include microorganisms other than those regarded in 2. 1. 1 and 2.2. 1. 3. PURPOSE OF MICROBIOLOGICAL CRITERIA FOR FOODS 3.1 The purpose of microbiological criteria for foods is to protect the health of the consumer by providing safe, sound and wholesome products and to meet the requirements of fair practices in trade. 4. GENERAL CONSIDERATIONS CONCERNING PRINCIPLES FOR ESTABLISHING AND APPLYING CRITERIA 4.1 The basis of control of microbiologically sensitive foods should be through the application of Codes of Practice. A microbiological criterion should be established and applied only where there is a definite need for it and where it can be shown to be effective and practical. Such need is demonstrated by epidemiological evidence that the particular food is a public health hazard, or where an assurance is required that the provisions of hygienic significance in the Code have been adhered to. The criterion should be technically attainable by good manufacturing practice so that it does not encourage the use of objectionable treatments in an attempt to reduce microorganisms to the acceptable level.
368 APPENDIX B 4.2 To fulfill the purposes of microbiological criteria, consideration should be given to · the evidence of hazards to health; · the microbiology of the raw material; · the effect of processing on the microbiology of the food; · the likelihood and consequences of microbial contamination and/or growth during subsequent handling and storage; · the category of consumers at risk; and · the cost/benefit ratio associated with the application of the criterion. 4.3 The number of samples tested shall be as stated in the sampling plan and shall not be exceeded. 4.4 To make the best use of limited resources of money and man- power, it is essential that only appropriate tests be applied to those foods and at those points during the processing and distribution of food that offer maximum benefit in providing the consumer with a safe, sound and wholesome food. 4.5 The need for inspection of the establishment including the pro- duction process should be considered. 5. INTERPRETATION OF RESULTS 5.1 When a product fails to meet a criterion, the action to be taken depends on the type of criterion and on the circumstances. If the limit exceeded is part of a standard, the product concerned must be rejected as unfit for its intended use; if it is part of an end-product specification, appropriate action should be taken to rectify the causative factor. It is optional whether any action is taken. When a limit in a guideline is exceeded, this should not necessarily result in rejection of product but should in general lead to the identification and correction of causative factors. 5.2 When product is rejected, there are in principle several options as to the action to be taken, depending on the findings and the circum- stances. Such options include sorting, reprocessing (e.g., by heating), and destruction, and may need to be specified in the criterion. In deciding on the option the major consideration should be to keep to a minimum the risk that unacceptable food reaches the consumer. However, food must not be needlessly destroyed nor declared unfit for human consumption. 6. COMPONENTS OF A MICROBIOLOGICAL CRITERION 6.1 Microorganisms of importance in a particular food 6.1.1 The microorganisms included in a criterion should be widely
APPENDIX B 369 accepted as relevant as pathogens, as indicator organisms or as spoil- age organisms to the particular food and technology. Organisms whose significance in the food is in doubt should not be included in a criterion. 6.1.2 The mere finding, with a presence-absence test, of certain organisms which have caused foodborne illness (e.g., Staphylococcus aureus, Clostridium perfringens and Vibrio parahaemolyticus) does not necessarily indicate a hazard. 6. 1.3 When choosing a test for an indicator organism, there should be a clear understanding as to whether the test for this organism is used to indicate an unsatisfactory manufacturing practice or whether it is used to indicate the possible presence of a pathogen. Where pathogens can be detected directly, a test for these should be used instead of tests for indicator organisms. 6.2 Microbiological methods 6. 2. 1 For use in a standard or end-product specification, methods elaborated by international organizations for a food or a group of foods should be preferred. For standards, and wherever possible for end- product specifications, only methods for which the reliability (accu- racy, reproducibility, inter- and intra-laboratory variation) has been statistically established in comparative or collaborative studies in sev- eral laboratories should be used. While reference methods to be used in standards and end-product specifications should be the most sen- sitive and reproducible for the purpose, methods to be used in guide- lines might often sacrifice to some degree sensitivity and reproducibility in the interests of speed and simplicity. They should, however, have been proved to give a sufficiently reliable estimate of the information needed. 6.2.2 When choosing a microbiological method as a reference method, consideration should be given to the universal availability of media, equipment, etc. 6.2.3 Methods which are applicable uniformly to various groups of commodities should be given preference over methods which apply only to individual commodities. Methods for testing rapidly perishable foods should be so designed that the results of microbiological ex- aminations can be available before the foods are consumed or exceed their shelf-life. 6.3 Microbiological limits 6.3. 1 Limits should be based on microbiological data appropriate to the food and to the kind of criterion in question. Limits for standards and end-product specifications should be based on data gathered at various stages of production, storage and distribution, while limits for guidelines could be based on data obtained from microbiological mon
370 APPENDIX B itoring during production. The numerical limits should take into con- sideration the risk associated with the organisms likely to affect the acceptability of the food, and the conditions under which the food is expected to be handled and consumed. Numerical limits should also take account of the distribution of microorganisms in the food and the inherent variability of the analytical procedure. 6.3.2 If a criterion requires a particular microorganism not to be detected, the size of sample shall be indicated. It should be borne in mind that no feasible sampling plan can ensure complete absence of a particular organism. 6.3.3 Microbiological limits can be related only to the time and place of sampling and not to the presumed number of microorganisms at an earlier or a later stage. As good manufacturing practice aims at producing foods with microbiological characteristics significantly bet- ter than those required by public health considerations, a numerical limit in a guideline may be more stringent than in a standard or an end-product specification. 6.4 Sampling plans 6.4.1 A sampling plan is the particular choice of sampling pro- cedure and the decision criteria to be applied to a lot, based on ex- amination of a prescribed number of sample units by defined methods. Sampling plans should be administratively and economically feasible. In particular, sampling plans should take into account the heteroge- neity of distribution of microorganisms. For standards and end-product specifications, 2- or 3-class attribute plans may find useful applica- tions. (See ICMSF Book 2.) 6.4.2 Wherever possible, the confidence limits of the sampling plans should be given. 7. SAMPLING METHODS AND HANDLING OF SAMPLES 7.1 The sampling method shall be defined in the sampling plan. The time between field sampling and analysis should be as short as possible, and during transport to the laboratory the conditions (e.g., temperature) should be appropriate to the food, so that the results reflect within the limitations given by the sampling plan the microbiological conditions of the lot presented for inspection. 8. REPORTING 8.1 The test report shall give the information needed for complete identification of the sample, the results, and the test method.
APPENDIX B 371 9. PROVISIONS FOR RECONSIDERATION AT REGULAR INTERVALS 9.1 Criteria should be reviewed and if necessary revised at three year intervals after their adoption by the Codex Alimentarius Commission.
