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Biofilm in milking equipment on a dairy farm as a potential source of bulk tank milk contamination with Listeria monocytogenes

Permanent URL:
http://handle.nal.usda.gov/10113/43295
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Abstract:
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.
Author(s):
Latorre, A.A. , Van Kessel, J.S. , Karns, J.S. , Zurakowski, M.J. , Pradhan, A.K. , Boor, K.J. , Jayarao, B.M. , Houser, B.A. , Daugherty, C.S. , Schukken, Y.H.
Subject(s):
biofilm , milking , milking equipment , dairy farming , bulk milk , food contamination , bacterial contamination , milk analysis , milk composition , Listeria monocytogenes , fouling
Format:
p. 2792-2802.
Note:
Includes references
Source:
Journal of dairy science 2010 June, v. 93, no. 6
Language:
English
Year:
2010
Collection:
Journal Articles, USDA Authors, Peer-Reviewed
Rights:
Works produced by employees of the U.S. Government as part of their official duties are not copyrighted within the U.S. The content of this document is not copyrighted.