Title: Use of Germicidal Ultra-Violet Light to Reduce Low Numbers of Listeria monocytogenes on Raw Chicken Meat Authors
Submitted to: Journal of Food Protection
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: July 19, 2013
Publication Date: N/A
Interpretive Summary: Listeria monocytogenes is a human pathogen that is associated with both raw and processed poultry meat products. In earlier research, we showed that raw poultry parts can be naturally contaminated with low numbers of this organism and as such represent the most important source of L. monocytogenes to commercial chicken cooking facilities. This, in turn, can result in contaminated fully cooked ready-to-eat poultry products. We tested a process designed to kill L. monocytogenes on raw chicken parts before shipment to the cooking plant. Germicidal ultra violet light was applied to broiler breast fillets previously inoculated with low numbers (35-60 cells) of L. monocytogenes. Treatment times tested included: 5 min, 3 min, 1 min, 30s, 15 s and 5s; the test was repeated five times for all treatments. We found that all treatment times significantly lessened the numbers of L. monocytogenes to the same degree resulting in an average of less than 1 cell per fillet. This method shows promise as a means to kill L. monocytogenes on raw poultry and stop the transfer of this pathogen from a broiler slaughter plant to a commercial cooking plant.
Technical Abstract: Listeria monocytogenes is a common constituent of the microbiological community in poultry processing plants and as such can be found in low numbers on raw poultry. Raw meat has been shown to be the most important source of this pathogen to commercial cooking facilities. Germicidal ultra violet (UV) light was tested as a means to kill L. monocytogenes inoculated onto broiler breast fillets. Treatments at 800 µW/cm2 ranging from 5 min to 5 s of exposure were tested against inoculums between 35 and 60 cells per fillet. All fillets were sampled by rinsing in enrichment broth and surviving pathogens were quantified using most probable number (MPN) analysis. Five replications each with 5 fillets per treatment were analyzed to achieve 25 samples per treatment. All treatment times resulted in a significant decrease in L. monocytogenes numbers compared to paired untreated controls. Treated samples retained from 0.2 to 1.5 MPN L. monocytogenes per fillet, with exposure time having no significant effect on the number of survivors. A five second treatment with germicidal UV light has potential as an intervention method to limit the transfer of L. monocytogenes from a slaughter plant to a cooking plant with raw broiler parts.