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United States Department of Agriculture

Agricultural Research Service

Research Project: INTERVENTIONS TO REDUCE FOODBORNE PATHOGENS IN SWINE AND CATTLE

Location: Food and Feed Safety Research

Title: Environmental prevalence and persistence of Listeria monocytogenes in cold-smoked trout processing plants

Authors
item Dimitrijevic, Mirjana -
item Anderson, Robin
item Karabasil, Nedjeljko -
item Pavlicevic, Natasa -
item Jovanovic, Snezana -
item Nedeljkovic-Trailovi, Jelena -
item Teodorovic, Vlado -
item Markovic, Maja -
item Dojcinovic, Slobodan -

Submitted to: Acta Veterinaria
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: March 10, 2011
Publication Date: September 1, 2011
Repository URL: http://handle.nal.usda.gov/10113/57222
Citation: Dimitrijevic, M., Anderson, R.C., Karabasil, N., Pavlicevic, N., Jovanovic, S., Nedeljkovic-Trailovi, J., Teodorovic, V., Markovic, M., Dojcinovic, S. 2011. Environmental prevalence and persistence of Listeria monocytogenes in cold-smoked trout processing plants. Acta Veterinaria. 61:429-442.

Interpretive Summary: Listeria monocytogenes is an important foodborne pathogen worldwide and is capable of growing in a variety of food-processing environments. In this study, the presence of Listeria monocytogenes on the surfaces of equipment and workers' hands during different production stages, as well as on fish skin and meat during processing and storage of cold-smoked trout, was investigated in Serbia. Listeria monocytogenes was recovered from 10 (6.06%) of a total 165 cotton-swabbed samples collected from the surfaces of equipment and workers' hands at two separate processing facilities. Of 105 samples collected from fish skin and meat during various production steps in both processing plants, 14 (13.33%) were confirmed culture-positive for L. monocytogenes, with recovery being most frequent in samples collected in the area before vacuum packaging. Recovery rates at two different Serbian processing plants did not differ (p<0.05) but suggested that different strains of L. monocytogenes resided within each processing plant and may have contributed to the final product contamination. We recovered L. monocytogenes from only 2 processed trout samples stored for up to 28 days at 4oC but recovered L. monocytogenes from 8 processed fish samples stored similarly at 10oC. Results from this study emphasize the importance of adhering to strict hygienic and processing standards at different stages of trout processing and storage. Ultimately, these results will help processors minimize the chances of L. monocytogenes contamination of cold-smoked trout.

Technical Abstract: The presence of Listeria monocytogenes on the surfaces of equipment and workers' hands during different production stages, as well as on fish skin and meat during processing and storage of cold-smoked trout, was investigated. Listeria monocytogenes was recovered from 10 (6.06%) of a total 165 cotton-swabbed samples collected from the surfaces of equipment and workers' hands at two separate processing facilities. Of 105 samples collected from fish skin and meat during various production steps in both processing plants, 14 (13.33%) were confirmed culture-positive for L. monocytogenes, with recovery being most frequent in samples collected in the area before vacuum packaging. Recovery rates at two different Serbian processing plants did not differ (p<0.05) but suggested that different L. monocytogenes serotypes appeared to be resident within each processing plant and may have contributed to the final product contamination. From all smoked trout samples collected during 7, 14, 21, and 28 days of storage at 4oC, only two were culture-positive for L. monocytogenes serotype 1/2a, and both of these were collected on the 7th day of storage. Conversely, 4, 3, and 1 sample(s) were contaminated with L. monocytogenes serotypes 1/2a and 1/2b after 7, 14, and 21 days storage at 10oC. Listeria monocytogenes was not recovered from smoked trout stored 28 days at 10oC. Results emphasize the importance of adhering to strict hygienic and quality control standards throughout the processing environment.

Last Modified: 10/22/2014
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