MFLP-70 Detection of Salmonella in Foods by the Modified 1-2 Test
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6D6C0CE5C1C2452100750700CF45E6EE |
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0.05 |
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13 |
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日期： |
2012-3-2 |
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Published by: POLYSCIENCE PUBLICATIONS, P.O. Box 1606, Station St-Martin, Laval, Quebec,Canada H7V 3P9. TEL.: 1-800-840-5870. FAX: (450) 688-1930.,Government of Canada Gouvernement du Canada,Laboratory Procedure MFLP-70,April 1995,HEALTH PROTECTION BRANCH,OTTAWA,DETECTION OF SALMONELLA IN FOODS BY THE,MODIFIED 1-2 TEST,Don Warburton1 and John Oggel2,1Bureau of Microbial Hazards, Food Directorate, Ottawa, Ontario, K1A 0L2,2Laboratory Services, Agri-Food and Agriculture Canada, Ottawa, Ontario, K1A 0C6,1. APPLICATION,The method is applicable to the detection of viable motile Salmonella from feeds, raw foods and other,samples. It is a suitable screening test, especially where follow up product action is not anticipated. When,product-based compliance action is anticipated, and where stipulated, the Official Methods and HPB,Method should be used. This revised method replaces MFLP-70, dated April 1994.,2. DESCRIPTION,The method has been shown to produce satisfactory results with naturally-contaminated animal feed,chicken, pork, seafood and artificially-contaminated foods in AOAC and HPB studies (8.3-8.6). This,method can be used successfully for the detection of motile Salmonella in other foods, food ingredients,and environmental samples.,3. PRINCIPLE,Following pre-enrichment and selective enrichment in tetrathionate brilliant green broth, the sidearm of the,1-2 Test is inoculated. Motile Salmonella grow through semi-solid medium and react with polyvalent H,(flagellar) antibodies to form an immunoband. This presumptive identification requires 48 h to complete.,It is not a confirmatory test because the polyvalent H antibodies may cross-react with a small percentage,of non-Salmonella. NB: This method does not detect non-motile salmonellae. Pathogenic, non-motile,strains have not been implicated in foodborne disease(s) since 1964 (8.5; E.C.D. Todd; pers. com.). Nonmotile,strains represent <1% of isolates from clinical samples and animal feeds (J. Oggel, AAFC and H.,Lior, HPB; pers. com.). Confirmatory biochemical and serological tests are performed on isolated colonies.,4. DEFINITION OF TERMS,See Appendix A of Volume 3.,5. COLLECTION OF SAMPLES,See Appendix B of Volume 3.,6. MATERIALS AND SPECIAL EQUIPMENT,1) 1-2 Test (BioControl Systems Inc., phone: (206) 487-2055, FAX: (206) 487-1476),2) Buffered Peptone Water (commercially available; Unipath, Ottawa),3) Nutrient broth (commercially available),MFLP-70,- 2 - April 1995,4) Skim milk medium (base is commercially available; Difco, Detroit, MI),5) Tetrathionate brilliant green broth (base is commercially available),6) EF-18 agar (EF-18, Gelman Scientific, Montreal, Qué.),7) Hektoen enteric agar (HEK; commercially available),8) Bismuth sulfite agar (BIS; Difco),9) Brillian green sulpha agar (BGS; Difco),10) Rambach agar (RAM; BDH, Toronto),11) Xylose-Lysine-deoxycholate agar (XLD; commercially available),12) Colworth Stomacher 400, blender or equivalent,13) Incubators capable of maintaining 35 ± 0.5oC and 43 ± 0.5oC,7. PROCEDURE,Each sample unit may be analyzed individually or the analytical units may be combined.,Carry out the test in accordance with the following instructions:,7.1 Handling of Sample Units,7.1.1 In the laboratory prior to analysis, except for shelf-stable foods, keep sample units,refrigerated (0-5oC) or frozen, depending on the nature of the product. Thaw frozen,samples in a refrigerator, or under time and temperature conditions which prevent,microbial growth or death.,7.1.2 Analyze sample units as soon as possible after their receipt in the laboratory.,7.2 Preparation for Analysis,7.2.1 Have ready sterile nutrient broth, buffered peptone water or skim milk medium.,7.2.2 Clean the surface of the working area with a suitable disinfectant.,7.3 Preparation of Sample,7.3.1 To ensure a truly representative analytical unit agitate liquids or free flowing materials,until the contents are homogeneous. If the sample unit is a solid, obtain the analytical,unit by taking a portion from several locations within the sample unit. To reduce the,workload, the analytical units may be combined for analysis. It is recommended that a,composite contain not more than 500 g.,7.3.2 Prepare a 1:10 dilution of the food by aseptically blending 25 g or mL (the analytical unit),into 225 ml of the required preenrichment broth, as indicated in Tables I and II.,7.3.3 Adjust the pH of the mixture, if necessary, to 6.8 ± 0.2 with 1 N NaOH or 1N HCl.,7.3.4 A positive and a negative control should be set up at the same time. It is imperative that,the positive control be a motile Salmonella. Test in motility agar.,7.3.5 Incubate pre-enrichment mixture and……
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