If a food processing plant was completely free of Listeria contamination, how long would it for Listeria to gain a foothold in the plant, and by what mechanisms would it spread? Friend of the program, Dr. Mark Berrang, shared some of his research in advance of a talk he plans to give here at Penn State this spring.
Starting with a brand new further-process chicken facility, he found that within 4 months, persistent strains of Listeria had established itself in the drains. The incoming meat was the primary source of Listeria. These strains remained even through cleaning and sanitizing of the operations. Once in the drains, Listeria could become easily aerosolized even from a intermittent 2 second spray of water. Reducing the incoming Listeria load is a challenge, and mitigation steps such as UV light may help.
As part of the Food Science Seminar Series, Dr. Berrang will discuss his work on Listeria in food processing facilities on March 1, 2018 at 4 pm in Room 252 Food Science. Please contact Dr. Jasna Kovac (jzk303@psu.edu) for more details.
Journal of Food Protection, Vol. 73, No. 2, 2010, Pages 286–291
Colonization of a Newly Constructed Commercial Chicken
Further Processing Plant with Listeria monocytogenes3
MARK E. BERRANG,1* RICHARD J. MEINERSMANN,1 JOSEPH F. FRANK,2 AND SCOTT R. LADELY1{
1U.S. Department of Agriculture, Agricultural Research Service, Russell Research Center, Athens, Georgia 30604-5677; and 2Food Science and Technology Department, University of Georgia, Athens, Georgia 30602, USA
MS 09-321: Received 29 July 2009/Accepted 19 October 2009
ABSTRACT
This study was undertaken to determine potential sources of Listeria monocytogenes in a newly constructed chicken further processing plant and document the eventual colonization of the facility by this pathogen. To ascertain the colonization status of the plant, floor drains were sampled after a production shift and again after a cleanup shift on roughly a monthly basis for 21 months. Potential sources of L. monocytogenes to the plant included incoming raw meat, incoming fresh air, and personnel. Nearby environment and community samples were also examined. All L. monocytogenes detected were subjected to DNA sequence–based subtyping. L. monocytogenes was not detected in the plant before the commencement of processing operations. Within 4 months, several subtypes of L. monocytogenes were detected in floor drains, both before and after cleaning and sanitizing operations. No L. monocytogenes was detected on filters for incoming air, samples associated with plant employees, or a nearby discount shopping center. One subtype of L. monocytogenes was detected in a natural stream near the plant; however, this subtype was never detected inside the plant. Eight subtypes of L. monocytogenes were detected in raw meat staged for further processing; one of the raw meat subtypes was indistinguishable from a persistent drain subtype recovered after cleaning on eight occasions in four different drains. Poultry further processing plants are likely to become colonized with L. monocytogenes; raw product is an important source of the organism to the plant
Journal of Food Protection, Vol. 75, No. 7, 2012, Pages 1328–1331
Generation of Airborne Listeria innocua from Model Floor Drains
MARK E. BERRANG1* AND JOSEPH F. FRANK2
1U.S. Department of Agriculture, Agricultural Research Service, Russell Research Center, Athens Georgia 30605; and 2Department of Food Science and
Technology, University of Georgia, Athens, Georgia 30602, USA
MS 12-021: Received 14 January 2012/Accepted 18 March 2012
ABSTRACT
Listeria monocytogenes can colonize floor drains in poultry processing and further processing facilities, remaining present even after cleaning and disinfection. Therefore, during wash down, workers exercise caution to avoid spraying hoses directly into drains in an effort to prevent the escape and transfer of drain microflora to food contact surfaces. The objective of this study was to examine the extent to which an inadvertent water spray into a colonized floor drain can cause the spread of airborne Listeria. Listeria innocua was used to inoculate a polyvinyl chloride model floor drain, resulting in approximately 108 cells per ml of phosphate-buffered saline and 104 attached cells per square centimeter of inner surface. Each model drain was subjected to a 2-s spray of tap water at 68.9 kPa from a distance of 1 m. Drains were sprayed while filled and again after emptying. Airborne cells
were collected by using sedimentation plates containing Listeria selective agar which were placed on the floor and walls of a contained room at incremental horizontal and vertical distances of 0.6, 1.2, 2.4, or 4.0 m from the drain. Sedimentation plates were exposed for 10 min. A mechanical sampler was used to also collect air by impaction on the surface of Listeria selective agar to determine the number of cells per liter of air. The experiment was conducted in triplicate rooms for each of four replications. L. innocua was detected on sedimentation plates on the floor as far as 4.0 m from the drain and on walls as high as 2.4 m above the floor and 4 m from the drain. A 2-s spray with a water hose into a contaminated drain can cause airborne spread of Listeria, resulting in the potential for cross-contamination of food contact surfaces, equipment, and exposed product.
JAPR: Research Report
Contamination of raw poultry meat by airborne Listeria originating from a floor drain 1
M. E. Berrang ,*2 J. F. Frank ,† and R. J. Meinersmann *
* USDA–Agricultural Research Service, Russell Research Center, Athens, GA 30605;
and † Department of Food Science and Technology, University of Georgia, Athens 30602
Primary Audience: Poultry Food Safety Researchers, Poultry Processors
SUMMARY
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 nonvirulent surrogate, Listeria 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 2-s water spray during which broiler breast fillets were left uncovered on a table 2.4 m away. Other fillets were indirectly exposed by placement on the table 10 min after the drain spray. The number of Listeria on each fillet was determined on the day of exposure and after 4 d 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 4 d of cold storage. An inadvertent 2-s spray into a contaminated floor drain could result in transfer of low numbers of Listeria to raw meat on a work surface.
Journal of Food Protection, Vol. 76, No. 11, 2013, Pages 1969–1971
Use of Germicidal UV Light To Reduce Low Numbers of Listeria monocytogenes on Raw Chicken Meat
M. E. BERRANG,1* R. J. MEINERSMANN,1 AND J. F. FRANK2
1U.S. Department of Agriculture, Agricultural Research Service, Russell Research Center, Athens, Georgia 30605; and 2Department of Food Science and
Technology, University of Georgia, Athens, Georgia 30602, USA
MS 13-181: Received 3 May 2013/Accepted 19 July 2013
ABSTRACT
Listeria monocytogenes is a common constituent of the microbiological community in poultry processing plants and can be found in low numbers on raw poultry. Raw meat is the most important source of this pathogen in commercial cooking facilities. Germicidal UV light was tested as a means to kill L. monocytogenes inoculated onto broiler breast fillets. Treatments at 800 mW/ cm2 for 5 s to 5 min of exposure were tested against inocula of 35 to 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 sample fillets per treatment. All treatment times resulted in a significant decrease in L. monocytogenes numbers compared with paired untreated controls. Treated samples retained 0.2 to 1.5 MPN L. monocytogenes per fillet, and exposure time had no significant effect on the number of surviving cells. A 5-s treatment with germicidal UV light has potential as an intervention method to limit the transfer of L. monocytogenes on raw skinless breast fillets from a slaughter plant to a cooking plant.
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