Submitted to: Journal of Food Protection
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: May 6, 2002
Publication Date: October 1, 2002
Citation: Berrang, M.E., Meinersmann, R.J., Northcutt, J.K., Smith, D.P. 2002. Molecular characterization of listeria monocytogenes isolated from a poultry further processing facility and fully cooked product. Journal of Food Protection. 65(10):1574-1579. Interpretive Summary: Listeria monocytogenes is a human food-borne pathogen that has been linked to fully cooked poultry meat. It is unclear exactly how fully cooked poultry meat becomes contaminated with L. monocytogenes. We took samples from the environment within a chicken cooking plant and examined them for the presence of L. monocytogenes. Using molecular subtyping methods, isolates that were detected from the facility were examined to determine if they were the same as other isolates detected on cooked meat processed in the same plant. L. monocytogenes isolates detected on cooked meat were not distinguishable from those detected in drains, on floors and on some product contact surfaces. These results can be used by poultry meat processors to help design sanitation procedures to prevent cross contamination of cooked meat.
Technical Abstract: This study was undertaken to explore environmental sources of L. monocytogenes in a commercial chicken further processing facility and to compare those isolates found to others detected on fully cooked product. A survey was conducted in the processing facility whereby forty environmental sites representing raw and cooked product areas of two production lines were cultured for L. monocytogenes. The resulting isolates were subjected to molecular subtyping by ribotyping and compared to twenty five isolates collected by plant personnel from product contact surfaces and fully cooked product. Eighty nine environmental and product isolates were divided into fourteen distinct ribogroups. Two ribogroups included isolates from fully cooked product; the members of these two ribogroups were subjected to further analysis by pulsed field gel electrophoresis resulting in four clusters. L. monocytogenes detected in fully cooked product from line 1 was found to be indistinguishable from isolates collected from: 1) the spiral freezer exit conveyor on line 1, 2) raw product contact surfaces on line 2 and 3) drains in the cooked area of line 2. L. monocytogenes from fully cooked product produced on line 2 was found to be indistinguishable from isolates collected from: 1) drains in the raw product side of line 2 and 2) floor surface in the cooked product area of line 2. These data show that L. monocytogenes may colonize a poultry further processing facility and eventually be transferred to fully cooked product.