MFHPB-20 Methods for the Isolation and Identification of Salmonella from Foods and Environmental Samples
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ID： |
DC8FE70C5D8B4C01BF92FC722B202301 |
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文件大小(MB)： |
0.05 |
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页数： |
16 |
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文件格式： |
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日期： |
2012-3-2 |
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文本摘录（文本识别可能有误，但文件阅览显示及打印正常，pdf文件可进行文字搜索定位）：
Published on the Food Directorate’s (Health Canada's) website at,http://www.hc-sc.gc.ca/fn-an/res-rech/analy-meth/microbio/index_e.php,Government of Canada Gouvernement du Canada,HPB Method MFHPB-20,March 2009,HEALTH PRODUCTS AND FOOD BRANCH,OTTAWA,ISOLATION AND IDENTIFICATION OF SALMONELLA FROM FOOD,AND ENVIRONMENTAL SAMPLES,Anne Reid,Research Division,Health Products and Food Branch,Health Canada, Postal locator: 2204E,Ottawa, Ontario, K1A 0K9,e-mail: Anne_Reid@hc-sc.gc.ca,Microbiological Methods Committee,Bureau of Microbial Hazards, Food Directorate,Health Products and Food Branch, Health Canada,Postal Locator: 2204E,Ottawa, Ontario K1A 0K9,1. APPLICATION,This method is applicable to the detection of viable Salmonella in foods and environmental samples to,determine compliance with the requirements of Sections 4 and 7 of the Food and Drugs Act and specific,Regulations (as summarized in the Interpretive Summary (7.15)). This revised method replaces MFHPB-,20, dated April 1998. Due to health and safety issues surrounding the use of selenite cystine, this revised,method should also be used in place of the Official Methods (Volume 1 of this Compendium) such as,MFO-6, MFO-10, MFO-11 and MFO-12.,This revised method includes the following major changes in the analytical approach for the detection of,foodborne Salmonella spp.:,1) The incorporation of Appendix J (November 2003) allowing the substitution of RVS,enrichment broth for SC enrichment broth for most food commodities.,2) The incorporation of MFHPB-20A (April 2002), for the analysis of seed used to,manufacture sprouts.,3) The inclusion of other selective media, including chromogenic media.,MFHPB-20,- 2 - March 2009,2. PRINCIPLE,The procedure consists of six distinct stages.,2.1 Non-Selective Enrichment (Pre-enrichment),The initial handling of the food and the non-selective enrichment stage (pre-enrichment) vary,according to the type of food examined (7.6). The test sample is inoculated into a non-inhibitory,liquid medium to favour the repair and growth of stressed or sublethally-injured salmonellae,arising from exposure to heat, freezing, desiccation, preservatives, high osmotic pressure or wide,temperature fluctuations (7.1, 7.6).,2.2 Selective Enrichment,Replicate portions of each pre-enrichment culture are inoculated into two enrichment media to,favour the proliferation of salmonellae through a selective inhibition of the growth of competing,microorganisms (7.4). The enrichment broth RVS (7.25 - 7.29) may be substituted for SC broth,for most food commodities (see the “Note” in Section 5, point 8 for exceptions).,2.3 Selective Plating,Enriched cultures are streaked onto selective and differential agars for the isolation of salmonellae,(7.5, 7.30).,2.4 Purification,Presumptive Salmonella isolates are purified on MacConkey agar plates. This removes the,possibility of viable but inhibited organisms from the selective agars contaminating the culture in,further tests.,2.5 Biochemical Screening,Isolates are screened using determinant biochemical reactions.,2.6 Serological Identification,Polyvalent and/or grouping somatic antisera are used to support the identification of isolates as,Salmonella. Cultures should be sent to a reference typing centre for complete serotyping.,3. DEFINITION OF TERMS,See Appendix A of Volume 2.,4. COLLECTION OF SAMPLES,4.1 Sampling,See Appendix B of Volume 2.,For routine sampling and analysis, 5 sample units of at least 100 g each should be collected from,each lot unless stipulated in Table I. Refer to the Interpretive Summary (7.15) for Guidelines and,Regulations specific to the foods being analysed for Salmonella.,For additional information concerning sampling plans in relation to degrees of risk and conditions,of use refer to ICSMF (7.16).,MFHPB-20,- 3 - March 2009,5. MATERIALS AND SPECIAL EQUIPMENT,Note: The Laboratory Supervisor must ensure that the analysis described in this method is carried out in,accordance with the International Standard referred to as “ISO/IEC 17025:2005 (or latest version):,General Requirements for the Competence of Testing and Calibration Laboratories".,The media and reagents listed below are commercially available and are to be used, prepared and/or,sterilized according to the manufacturer's instructions. See Appendix G of Volume 2 for the media,formula.,Note: If the analyst uses any variations of the media listed here (either product that is commercially available or,made from scratch), it is the responsibility of the analyst or Laboratory Supervisor to ensure equivalency.,1) Nutrient Broth (NB),2) Trypticase (Tryptic, Tryptone) Soy Broth,3) Brilliant Green Water,4) B……
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