Title: Contamination of raw poultry meat by airborne listeria originating from a floor drain Authors
Submitted to: Meeting Abstract
Publication Type: Abstract Only
Publication Acceptance Date: May 17, 2012
Publication Date: July 9, 2012
Citation: Berrang, M.E., Frank, J.F., Meinersmann, R.J. 2012. Contamination of raw poultry meat by airborne listeria originating from a floor drain [abstract]. Poultry Science. 91(Suppl.1):156-157. Technical Abstract: Poultry processing plants can become colonized with Listeria resulting in long term residence in floor drains. Earlier work showed that an inadvertent two second water spray into a contaminated floor drain causes airborne dissemination of low numbers of Listeria cells. The objective of the current study was to determine the extent to which drain spray can result in the transfer of Listeria to raw poultry meat. Meat was exposed directly to contaminated air during drain spray or indirectly by placement on an exposed surface after the drain was sprayed. Non-virulent L. innocua was used to inoculate PVC model floor drains resulting in approximately 108 cells per mL of PBS and 104 attached cells per cm2 inner surface. In a containment room, a model drain was subjected to a 2 s spray of tap water at 68.9 kPa from a distance of one meter. On a stainless steel table eight feet from the drain, ten fresh boneless skinless broiler breast halves were left uncovered during the drain spray and for an additional 10 minutes. After collection of the direct exposed breast halves, another ten halves were placed on the table between the spaces previously covered by direct exposed breast meat. The second set of breast halves were allowed to remain on the table for 10 minutes. After either direct or in-direct exposure to the airborne Listeria, all breast halves were individually placed into clean re-sealable plastic bags and covered with ice. Ten un-exposed control breast halves remained in re-sealable bags throughout the experiment. Five breast halves from each group were subjected to an immediate 60 second rinse with 100 mL Listeria enrichment broth while the other five were held at 5 C for 7 days before rinsing. Rinsate was collected and used to conduct a three tube most probable number technique using the USDA-Food Safety Inspection culture method to estimate the number of Listeria detected on each breast half. Three replications were conducted. The mean log number cfu detected per breast half directly exposed to the air was 1.5 on the day of exposure and 2.9 after seven days of refrigerated storage. For breast halves exposed by surface contact, the mean log number cfu detected was 1.2 on the day of exposure and 2.3 after seven days of storage. These data demonstrate one possible means of Listeria transfer from a contaminated floor drain to processed poultry meat.