Submitted to: Journal of Applied Poultry Research
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 11/26/2012
Publication Date: 3/1/2013
Citation: Berrang, M.E., Frank, J.F., Meinersmann, R.J. 2013. Contamination of raw poultry meat by airborne Listeria originating from a floor drain. Journal of Applied Poultry Research. 22(1):132-136.
Interpretive Summary: Listeria monocytogenes is a human pathogen that has been associated with poultry products. This organism is part of the normal flora in poultry processing plants, it can persist in floor drains and is transferred from chicken slaughter plants cooking plants with incoming raw product. In earlier work, we showed that a two second hose spray into a floor drain can result in Listeria becoming airborne. The objective of the current study was to determine to what extent Listeria can transfer to raw poultry meat during a water spray into a contaminated floor drain. Using a non-pathogenic surrogate, L. innocua, we inoculated model drains, subjected them to a two second water spray and measured the number of Listeria detected on broiler breast fillets left on a table during the spray or placed on an exposed stainless steel surface 10 minutes after the spray. An average of 18 Listeria cells were found on breast fillets exposed to the airborne cells, this number did not change significantly during four days of refrigerated storage. When only exposed by contact with a contaminated surface, an average of 7 cells were detected per breast fillet. These data demonstrate the potential for meat to become contaminated in a processing plant due to normal wash down procedures. More research is planned to design and test interventions that can be applied to eliminate low levels of Listeria at the slaughter plant before the organism is transferred to commercial chicken cooking facilities.
Technical Abstract: Poultry processing plants can become colonized with Listeria monocytogenes resulting in long term residence in floor drains. Earlier work showed that water spray into a contaminated floor drain causes airborne dissemination of a non-virulent surrogate, L. innocua. The objective of the current study was to determine the extent to which a hose spray can result in the transfer of L. innocua from an established floor drain biofilm to raw poultry meat. Model floor drains were inoculated and subjected to a two second water spray during which broiler breast fillets were left uncovered on a table 2.4 meters away. Other fillets were indirectly exposed by placement on the table ten minutes after the drain spray. The number of Listeria on each fillet was determined on the day of exposure and after four days of refrigerated storage. An average of approximately 18 Listeria cells was detected per air-exposed filet; about half that number was detected on indirectly exposed fillets. The number of Listeria did not change substantially during four days of cold storage. An inadvertent two second spray into a contaminated floor drain could result in transfer of low numbers of Listeria to raw meat on a work surface.