Biofilm in milking equipment on a dairy farm as a potential source of bulk tank milk contamination with Listeria monocytogenes
| Autor: | Bhushan M. Jayarao, Alejandra A. Latorre, M.J. Zurakowski, Ynte H. Schukken, J.S. Van Kessel, C.S. Daugherty, Abani K. Pradhan, Kathryn J. Boor, B.A. Houser, Jeffrey S. Karns |
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| Rok vydání: | 2010 |
| Předmět: |
Food Handling
Food Contamination medicine.disease_cause Polymerase Chain Reaction Milking fluids and secretions Listeria monocytogenes Genetics medicine Animals Bulk tank Food science biology food and beverages Contamination Raw milk biology.organism_classification Electrophoresis Gel Pulsed-Field Dairying Milk Biofilms Microscopy Electron Scanning Listeria Environmental science Cattle Animal Science and Zoology Sample collection Food Science Food contaminant |
| Zdroj: | Journal of Dairy Science. 93:2792-2802 |
| ISSN: | 0022-0302 |
| DOI: | 10.3168/jds.2009-2717 |
| Popis: | The objective of this study was to assess the presence of a Listeria monocytogenes-containing biofilm in milking equipment as a potential source of bulk tank milk contamination on a dairy farm where milk contamination had been previously documented. Samples were collected from milking equipment and milking parlor premises on 4 occasions and analyzed for the presence of L. monocytogenes. Pulsed-field gel electrophoresis (PFGE) typing was conducted on L. monocytogenes isolates from the milking equipment, parlor and storage room floors, bulk tank milk, and in-line milk filters. Pieces from milk meters and rubber liners were obtained to visually assess the presence of a biofilm using scanning electron microscopy. A total of 6 (15%), 4 (25%), and 1 (6%) samples were culture-positive for L. monocytogenes in the first, second, and third sample collection, respectively. Two samples were L. monocytogenes hly PCR-positive but were culture-negative in the fourth sample collection. Combined AscI and ApaI restriction analysis yielded 6 PFGE types for 15 L. monocytogenes isolates obtained from milking equipment, parlor, bulk tank milk, and milk filters. A predominant and persistent PFGE type (PFGE type T) was observed among these L. monocytogenes isolates (9/15 isolates). Scanning electron microscopy of samples from the bottom cover of 2 milk meters showed the presence of individual and clusters of bacteria, mainly associated with surface scratches. The presence of a bacterial biofilm was observed on the bottom covers of the 2 milk meters. Prevention of the establishment of biofilms in milking equipment is a crucial step in fulfilling the requirement of safe, high-quality milk. |
| Databáze: | OpenAIRE |
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