Current detection methods require at least one 24-48 hour enrichment step for the detection of Salmonella. This poses a problem because product often needs to be shipped before microbial contamination levels can be adequately ascertained. Therefore, the need for more rapid methods of Salmonella detection becomes apparent.
The purpose of this thesis was to determine if an immunologically-based method, Immunomagnetic Capture(IMC) -ELISA and molecular-based detection methods, PCR and Taqman® PCR employing IMC without enrichment, could detect at least 102 cfu/ml of S. Typhimurium in broiler carcass rinse fluid (CRF) samples.
IMC-ELISA, IMC-PCR, and IMC-Taqman® PCR were initially tested using 0 to 106 cfu/ml of pure culture S. Typhimurium. Each detection method was tested using artificially contaminated CRF samples. Finally, standardized IMC-ELISA, IMC-PCR, and IMC-Taqman® PCR methods were tested using commercial CRF samples. Salmonella concentrations were verified using a traditional plate method.
IMC-ELISA produced consistent results when detecting at least 104 to 106 cfu/mL of pure culture S. Typhimurium. IMC-ELISA was not able to produce repeatable results when testing artificially contaminated CRF samples. S. Typhimurium was not detected in commercial CRF samples which by virtue of direct plating on XLT-4 were found to contain essentially no Salmonella (<1 cfu/ml).
IMC-PCR was able to consistently detect 102 cfu/ml, whereas IMC-Taqman® PCR was able to detect 101 cfu/ml of pure culture S. Typhimurium. IMC-PCR, required four hours to complete, and it consistently detected 104 cfu/ml of S. Typhimurium in artificially contaminated CRF samples. IMC-Taqman® PCR took 3 hours to perform and was able to detect 103 cfu/ml S. Typhimurium in artificially contaminated CRF samples. The sensitivity, as well as the decreased time requirements of these detection methods, would suggest their usefulness in a commercial processing setting. / Master of Science
| Identifer | oai:union.ndltd.org:VTETD/oai:vtechworks.lib.vt.edu:10919/34159 |
| Date | 30 July 2002 |
| Creators | Sharp, Jennifer M. |
| Contributors | Veterinary Medical Sciences, Sumner, Susan S., Pierson, Frank William, Sriranganathan, Nammalwar |
| Publisher | Virginia Tech |
| Source Sets | Virginia Tech Theses and Dissertation |
| Detected Language | English |
| Type | Thesis |
| Format | application/pdf |
| Rights | In Copyright, http://rightsstatements.org/vocab/InC/1.0/ |
| Relation | sharpthesis072502.pdf |
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