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Catherine W Donnelly - One of the best experts on this subject based on the ideXlab platform.
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Combined secondary enrichment of primary enrichment broths increases Listeria detection.
Journal of Food Protection, 1999Co-Authors: Todd J Pritchard, Catherine W DonnellyAbstract:The efficacy of combining dual primary enrichment cultures into a single secondary broth was evaluated for detecting Listeria in naturally contaminated meats and environmental samples obtained from Dairy Processing Plants. A total of 336 samples were tested using University of Vermont modified Listeria enrichment broth (UVM) and Listeria repair broth containing selective agents (LRBS) as primary enrichment media. Eighty samples (23.8%) yielded Listeria by at least one method. Neither primary enrichment broth was significantly better (P>0.05) than the other in identifying Listeria-positive samples. UVM media, when used as a primary enrichment broth, identified 66 Listeria-positive samples, while the use of LRBS as a primary enrichment broth identified 65 Listeria-positive samples. Listeria detection improved significantly (P 0.05) in either procedure. Inoculum size (0.1 ml versus 0.2 ml) did not have an effect on the overall rate of recovery. The procedure developed increased the sensitivity of testing while decreasing the potential workload associated with an increase in enrichment procedures.
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comparison of the incidence of listeria on equipment versus environmental sites within Dairy Processing Plants
International Journal of Food Microbiology, 1995Co-Authors: Todd J Pritchard, Kathy J Flanders, Catherine W DonnellyAbstract:Abstract This study was undertaken to compare the incidence of Listeria contamination of Processing equipment with that of the general Dairy Processing environment. A total of 378 sponge samples obtained from 21 Dairy Plants were analyzed for Listeria using three different enrichment media. Use of extended microbiological analysis allowed us to identify 26 Listeria positive sites which would have not been identified had a single test format been employed. Eighty (80) of 378 sites (21.2%) were identified as Listeria positive. Listeria innocua was isolated from 59 of the 80 (73.8%) positive samples, L. Monocytogenes was identified in 35 (43.8%) of the positive samples, and L. Seeligeri was isolated from 5 (6.3%) of the Listeria positive samples. Positive equipment samples were obtained from 6 of the 21 (28.6%) Plants and 19 of the 21 (90.5%) Plants had positive environmental sites. Seventeen of the 215 (7.9%) samples from equipment were positive for Listeria species. Eleven of these sites, including 3 holding tanks, 2 table tops, 3 conveyor/chain systems, a pasta filata wheel, a pint milk filler and a brine pre-filter machine, were positive for L. monocytogenes. Nineteen of the 21 (90.5%) Plants had positive environmental sites. Sixty-three of the 163 (41.1%) samples from environmental sites were Listeria positive and 24 were positive for L. monocytogenes. Two-tailed student t-test analysis of the mean frequencies indicated that the level of contamination was significantly higher (p
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Comparison of the incidence of Listeria on equipment versus environmental sites within Dairy Processing Plants
International Journal of Food Microbiology, 1995Co-Authors: Todd J Pritchard, Kathy J Flanders, Catherine W DonnellyAbstract:This study was undertaken to compare the incidence of Listeria contamination of Processing equipment with that of the general Dairy Processing environment. A total of 378 sponge samples obtained from 21 Dairy Plants were analyzed for Listeria using three different enrichment media. Use of extended microbiological analysis allowed us to identify 26 Listeria positive sites which would have not been identified had a single test format been employed. Eighty (80) of 378 sites (21.2%) were identified as Listeria positive. Listeria innocua was isolated from 59 of the 80 (73.8%) positive samples, L. monocytogenes was identified in 35 (43.8%) of the positive samples, and L. seeligeri was isolated from 5 (6.3%) of the Listeria positive samples. Positive equipment samples were obtained from 6 of the 21 (28.6%) Plants and 19 of the 21 (90.5%) Plants had positive environmental sites. Seventeen of the 215 (7.9%) samples from equipment were positive for Listeria species. Eleven of these sites, including 3 holding tanks, 2 table tops, 3 conveyor/chain systems, a pasta filata wheel, a pint milk filler and a brine pre-filter machine, were positive for L. monocytogenes. Nineteen of the 21 (90.5%) Plants had positive environmental sites. Sixty-three of the 163 (41.1%) samples from environmental sites were Listeria positive and 24 were positive for L. monocytogenes. Two-tailed student t-test analysis of the mean frequencies indicated that the level of contamination was significantly higher (p < 0.001) in 'environmental' (49.7%) as opposed to 'equipment' samples (7.0%). Our study indicates that environmental contamination with Listeria does not necessarily translate into contamination of equipment within the same plant, and that greater emphasis needs to be placed on the cleaning and sanitizing of the plant environment.
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environmental surveillance of Dairy Processing Plants for the presence of yersinia species
Journal of Food Protection, 1995Co-Authors: Todd J Pritchard, Constance M Beliveau, Kathy J Flanders, Catherine W DonnellyAbstract:Thirty Dairy Processing Plants were surveyed to determine if the psychrotrophic nature of Yersinia influenced its environmental niche within the Plants. Three hundred forty-seven samples obtained from 30 Dairy Processing Plants were tested for the presence of Yersinia spp. Ten (33.3%) Plants had one or more positive sites. A total of 20 of the 347 (5.8%) sites tested were positive for one or more species of Yersinia. Yersinia enterocolitica was present at 85% (17/20) of the positive sites. It was identified by itself on 15 occasions and twice with other species of Yersinia. Other species identified included Yersinia ruckeri in 3 of the 20 positive samples (15%); Yersinia kristensenii and Yersinia frederiksenii both in 1 of the 20 (5%) positive samples. Ten of the 20 (50%) positive samples were obtained from coolers and entrances to freezers. Yersinia-positive cooler/freezer sites were obtained from 9 of the 10 positive Plants. The remaining 10 Yersinia-positive sites were from raw milk receiving areas (4/...
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Enhanced Recovery of Listeria from Dairy-Plant Processing Environments through Combined Use of Repair Enrichment and Selective Enrichment/Detection Procedures.
Journal of Food Protection, 1995Co-Authors: Kathy J Flanders, Todd J Pritchard, Catherine W DonnellyAbstract:The efficacy of using a repair step to increase sensitivity of recovery of injured Listeria from environmental sources in Dairy Processing Plants was investigated. The USDA-FSIS Listeria isolation protocol using UVM-modified Listeria enrichment broth medium University of Vermont (UVM) for primary enrichment was the standard method chosen for comparison. UVM broth was used in conjunction with rapid methods (Organon Teknika and Gene-Trak™), following manufacturer's guidelines. Listeria Repair Broth (LRB) was used as the repair enrichment medium in modified protocols of the standard and rapid procedures. LRB employs a nonselective period (2–5 hours) for repair of injured Listeria prior to selective-agent addition. Of 80 environmental sites positive by any method, UVM and LRB showed similar recovery rates (87.5% and 88.8%, respectively). Thus LRB provided little advantage over current procedures for use in contaminated sites. UVM was superior when used in conjunction with either rapid method. The USDA and mod...
Todd J Pritchard - One of the best experts on this subject based on the ideXlab platform.
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Combined secondary enrichment of primary enrichment broths increases Listeria detection.
Journal of Food Protection, 1999Co-Authors: Todd J Pritchard, Catherine W DonnellyAbstract:The efficacy of combining dual primary enrichment cultures into a single secondary broth was evaluated for detecting Listeria in naturally contaminated meats and environmental samples obtained from Dairy Processing Plants. A total of 336 samples were tested using University of Vermont modified Listeria enrichment broth (UVM) and Listeria repair broth containing selective agents (LRBS) as primary enrichment media. Eighty samples (23.8%) yielded Listeria by at least one method. Neither primary enrichment broth was significantly better (P>0.05) than the other in identifying Listeria-positive samples. UVM media, when used as a primary enrichment broth, identified 66 Listeria-positive samples, while the use of LRBS as a primary enrichment broth identified 65 Listeria-positive samples. Listeria detection improved significantly (P 0.05) in either procedure. Inoculum size (0.1 ml versus 0.2 ml) did not have an effect on the overall rate of recovery. The procedure developed increased the sensitivity of testing while decreasing the potential workload associated with an increase in enrichment procedures.
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comparison of the incidence of listeria on equipment versus environmental sites within Dairy Processing Plants
International Journal of Food Microbiology, 1995Co-Authors: Todd J Pritchard, Kathy J Flanders, Catherine W DonnellyAbstract:Abstract This study was undertaken to compare the incidence of Listeria contamination of Processing equipment with that of the general Dairy Processing environment. A total of 378 sponge samples obtained from 21 Dairy Plants were analyzed for Listeria using three different enrichment media. Use of extended microbiological analysis allowed us to identify 26 Listeria positive sites which would have not been identified had a single test format been employed. Eighty (80) of 378 sites (21.2%) were identified as Listeria positive. Listeria innocua was isolated from 59 of the 80 (73.8%) positive samples, L. Monocytogenes was identified in 35 (43.8%) of the positive samples, and L. Seeligeri was isolated from 5 (6.3%) of the Listeria positive samples. Positive equipment samples were obtained from 6 of the 21 (28.6%) Plants and 19 of the 21 (90.5%) Plants had positive environmental sites. Seventeen of the 215 (7.9%) samples from equipment were positive for Listeria species. Eleven of these sites, including 3 holding tanks, 2 table tops, 3 conveyor/chain systems, a pasta filata wheel, a pint milk filler and a brine pre-filter machine, were positive for L. monocytogenes. Nineteen of the 21 (90.5%) Plants had positive environmental sites. Sixty-three of the 163 (41.1%) samples from environmental sites were Listeria positive and 24 were positive for L. monocytogenes. Two-tailed student t-test analysis of the mean frequencies indicated that the level of contamination was significantly higher (p
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Comparison of the incidence of Listeria on equipment versus environmental sites within Dairy Processing Plants
International Journal of Food Microbiology, 1995Co-Authors: Todd J Pritchard, Kathy J Flanders, Catherine W DonnellyAbstract:This study was undertaken to compare the incidence of Listeria contamination of Processing equipment with that of the general Dairy Processing environment. A total of 378 sponge samples obtained from 21 Dairy Plants were analyzed for Listeria using three different enrichment media. Use of extended microbiological analysis allowed us to identify 26 Listeria positive sites which would have not been identified had a single test format been employed. Eighty (80) of 378 sites (21.2%) were identified as Listeria positive. Listeria innocua was isolated from 59 of the 80 (73.8%) positive samples, L. monocytogenes was identified in 35 (43.8%) of the positive samples, and L. seeligeri was isolated from 5 (6.3%) of the Listeria positive samples. Positive equipment samples were obtained from 6 of the 21 (28.6%) Plants and 19 of the 21 (90.5%) Plants had positive environmental sites. Seventeen of the 215 (7.9%) samples from equipment were positive for Listeria species. Eleven of these sites, including 3 holding tanks, 2 table tops, 3 conveyor/chain systems, a pasta filata wheel, a pint milk filler and a brine pre-filter machine, were positive for L. monocytogenes. Nineteen of the 21 (90.5%) Plants had positive environmental sites. Sixty-three of the 163 (41.1%) samples from environmental sites were Listeria positive and 24 were positive for L. monocytogenes. Two-tailed student t-test analysis of the mean frequencies indicated that the level of contamination was significantly higher (p < 0.001) in 'environmental' (49.7%) as opposed to 'equipment' samples (7.0%). Our study indicates that environmental contamination with Listeria does not necessarily translate into contamination of equipment within the same plant, and that greater emphasis needs to be placed on the cleaning and sanitizing of the plant environment.
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environmental surveillance of Dairy Processing Plants for the presence of yersinia species
Journal of Food Protection, 1995Co-Authors: Todd J Pritchard, Constance M Beliveau, Kathy J Flanders, Catherine W DonnellyAbstract:Thirty Dairy Processing Plants were surveyed to determine if the psychrotrophic nature of Yersinia influenced its environmental niche within the Plants. Three hundred forty-seven samples obtained from 30 Dairy Processing Plants were tested for the presence of Yersinia spp. Ten (33.3%) Plants had one or more positive sites. A total of 20 of the 347 (5.8%) sites tested were positive for one or more species of Yersinia. Yersinia enterocolitica was present at 85% (17/20) of the positive sites. It was identified by itself on 15 occasions and twice with other species of Yersinia. Other species identified included Yersinia ruckeri in 3 of the 20 positive samples (15%); Yersinia kristensenii and Yersinia frederiksenii both in 1 of the 20 (5%) positive samples. Ten of the 20 (50%) positive samples were obtained from coolers and entrances to freezers. Yersinia-positive cooler/freezer sites were obtained from 9 of the 10 positive Plants. The remaining 10 Yersinia-positive sites were from raw milk receiving areas (4/...
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Enhanced Recovery of Listeria from Dairy-Plant Processing Environments through Combined Use of Repair Enrichment and Selective Enrichment/Detection Procedures.
Journal of Food Protection, 1995Co-Authors: Kathy J Flanders, Todd J Pritchard, Catherine W DonnellyAbstract:The efficacy of using a repair step to increase sensitivity of recovery of injured Listeria from environmental sources in Dairy Processing Plants was investigated. The USDA-FSIS Listeria isolation protocol using UVM-modified Listeria enrichment broth medium University of Vermont (UVM) for primary enrichment was the standard method chosen for comparison. UVM broth was used in conjunction with rapid methods (Organon Teknika and Gene-Trak™), following manufacturer's guidelines. Listeria Repair Broth (LRB) was used as the repair enrichment medium in modified protocols of the standard and rapid procedures. LRB employs a nonselective period (2–5 hours) for repair of injured Listeria prior to selective-agent addition. Of 80 environmental sites positive by any method, UVM and LRB showed similar recovery rates (87.5% and 88.8%, respectively). Thus LRB provided little advantage over current procedures for use in contaminated sites. UVM was superior when used in conjunction with either rapid method. The USDA and mod...
Kathryn J Boor - One of the best experts on this subject based on the ideXlab platform.
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Genetic diversity and spoilage potentials among Pseudomonas spp. isolated from fluid milk products and Dairy Processing Plants
Applied and Environmental Microbiology, 2003Co-Authors: Belgin Dogan, Kathryn J BoorAbstract:Degradation of milk components through various enzymatic activities associated with the contamination of Dairy products by Pseudomonas spp. can reduce the shelf life of processed milk. Reliable methods for differentiating among Pseudomonas spp. strains are necessary to identify and eliminate specific sources of bacterial contamination from Dairy Processing systems. To that end, we assessed the genetic diversity and Dairy product spoilage potentials among a total of 338 Pseudomonas spp. isolates from raw and pasteurized milk and from environmental samples collected from four Dairy Processing Plants. The majority of isolates were identified as P. fluorescens and P. putida by API 20 NE. A total of 42 different ribotype patterns were identified among a subset of 81 isolates. The presence of many different ribotypes within this collection indicates high genetic diversity among the isolates and suggests multiple origins of contamination within the Processing plant and in Dairy products. The extracellular enzyme activity patterns among Pseudomonas isolates appeared to be associated with ribotypes. Isolates with the same ribotype frequently had the same extracellular protease, lecithinase, and lipase activities. For example, isolates grouped in ribotype 55-S-6 had the highest extracellular protease activity, while those in ribotypes 50-S-8 and 72-S-3 had the highest extracellular lipase activities. We conclude that ribotyping provides a reliable method for differentiating Pseudomonas strains with Dairy food spoilage potential.
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Fluid milk vitamin fortification compliance in New York State.
Journal of Dairy Science, 2001Co-Authors: S.c. Murphy, L.j. Whited, Lorraine Rosenberry, B.h. Hammond, D.k. Bandler, Kathryn J BoorAbstract:Current US regulations, as specified in the Pasteurized Milk Ordinance, require vitamin A fortification of all reduced fat fluid milk products. The addition of vitamin D is optional in all fluid products. Acceptable vitamin concentrations in fortified milks are 2000 to 3000 International units per quart for vitamin A and 400 to 600 International units per quart for vitamin D. Vitamin A and D levels were analyzed in fortified milk products collected over a 4-yr period in New York State. Samples of whole fat, 2% fat, 1% fat, and nonfat milks were collected twice per year from up to 31 Dairy Processing Plants. For vitamin A, 44.5% of 516 samples were in compliance with current regulations, and 47.7% of 648 samples were within the acceptable range for vitamin D. Most milk samples that were out of compliance were underfortified.
Kathy J Flanders - One of the best experts on this subject based on the ideXlab platform.
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comparison of the incidence of listeria on equipment versus environmental sites within Dairy Processing Plants
International Journal of Food Microbiology, 1995Co-Authors: Todd J Pritchard, Kathy J Flanders, Catherine W DonnellyAbstract:Abstract This study was undertaken to compare the incidence of Listeria contamination of Processing equipment with that of the general Dairy Processing environment. A total of 378 sponge samples obtained from 21 Dairy Plants were analyzed for Listeria using three different enrichment media. Use of extended microbiological analysis allowed us to identify 26 Listeria positive sites which would have not been identified had a single test format been employed. Eighty (80) of 378 sites (21.2%) were identified as Listeria positive. Listeria innocua was isolated from 59 of the 80 (73.8%) positive samples, L. Monocytogenes was identified in 35 (43.8%) of the positive samples, and L. Seeligeri was isolated from 5 (6.3%) of the Listeria positive samples. Positive equipment samples were obtained from 6 of the 21 (28.6%) Plants and 19 of the 21 (90.5%) Plants had positive environmental sites. Seventeen of the 215 (7.9%) samples from equipment were positive for Listeria species. Eleven of these sites, including 3 holding tanks, 2 table tops, 3 conveyor/chain systems, a pasta filata wheel, a pint milk filler and a brine pre-filter machine, were positive for L. monocytogenes. Nineteen of the 21 (90.5%) Plants had positive environmental sites. Sixty-three of the 163 (41.1%) samples from environmental sites were Listeria positive and 24 were positive for L. monocytogenes. Two-tailed student t-test analysis of the mean frequencies indicated that the level of contamination was significantly higher (p
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Comparison of the incidence of Listeria on equipment versus environmental sites within Dairy Processing Plants
International Journal of Food Microbiology, 1995Co-Authors: Todd J Pritchard, Kathy J Flanders, Catherine W DonnellyAbstract:This study was undertaken to compare the incidence of Listeria contamination of Processing equipment with that of the general Dairy Processing environment. A total of 378 sponge samples obtained from 21 Dairy Plants were analyzed for Listeria using three different enrichment media. Use of extended microbiological analysis allowed us to identify 26 Listeria positive sites which would have not been identified had a single test format been employed. Eighty (80) of 378 sites (21.2%) were identified as Listeria positive. Listeria innocua was isolated from 59 of the 80 (73.8%) positive samples, L. monocytogenes was identified in 35 (43.8%) of the positive samples, and L. seeligeri was isolated from 5 (6.3%) of the Listeria positive samples. Positive equipment samples were obtained from 6 of the 21 (28.6%) Plants and 19 of the 21 (90.5%) Plants had positive environmental sites. Seventeen of the 215 (7.9%) samples from equipment were positive for Listeria species. Eleven of these sites, including 3 holding tanks, 2 table tops, 3 conveyor/chain systems, a pasta filata wheel, a pint milk filler and a brine pre-filter machine, were positive for L. monocytogenes. Nineteen of the 21 (90.5%) Plants had positive environmental sites. Sixty-three of the 163 (41.1%) samples from environmental sites were Listeria positive and 24 were positive for L. monocytogenes. Two-tailed student t-test analysis of the mean frequencies indicated that the level of contamination was significantly higher (p < 0.001) in 'environmental' (49.7%) as opposed to 'equipment' samples (7.0%). Our study indicates that environmental contamination with Listeria does not necessarily translate into contamination of equipment within the same plant, and that greater emphasis needs to be placed on the cleaning and sanitizing of the plant environment.
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environmental surveillance of Dairy Processing Plants for the presence of yersinia species
Journal of Food Protection, 1995Co-Authors: Todd J Pritchard, Constance M Beliveau, Kathy J Flanders, Catherine W DonnellyAbstract:Thirty Dairy Processing Plants were surveyed to determine if the psychrotrophic nature of Yersinia influenced its environmental niche within the Plants. Three hundred forty-seven samples obtained from 30 Dairy Processing Plants were tested for the presence of Yersinia spp. Ten (33.3%) Plants had one or more positive sites. A total of 20 of the 347 (5.8%) sites tested were positive for one or more species of Yersinia. Yersinia enterocolitica was present at 85% (17/20) of the positive sites. It was identified by itself on 15 occasions and twice with other species of Yersinia. Other species identified included Yersinia ruckeri in 3 of the 20 positive samples (15%); Yersinia kristensenii and Yersinia frederiksenii both in 1 of the 20 (5%) positive samples. Ten of the 20 (50%) positive samples were obtained from coolers and entrances to freezers. Yersinia-positive cooler/freezer sites were obtained from 9 of the 10 positive Plants. The remaining 10 Yersinia-positive sites were from raw milk receiving areas (4/...
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Enhanced Recovery of Listeria from Dairy-Plant Processing Environments through Combined Use of Repair Enrichment and Selective Enrichment/Detection Procedures.
Journal of Food Protection, 1995Co-Authors: Kathy J Flanders, Todd J Pritchard, Catherine W DonnellyAbstract:The efficacy of using a repair step to increase sensitivity of recovery of injured Listeria from environmental sources in Dairy Processing Plants was investigated. The USDA-FSIS Listeria isolation protocol using UVM-modified Listeria enrichment broth medium University of Vermont (UVM) for primary enrichment was the standard method chosen for comparison. UVM broth was used in conjunction with rapid methods (Organon Teknika and Gene-Trak™), following manufacturer's guidelines. Listeria Repair Broth (LRB) was used as the repair enrichment medium in modified protocols of the standard and rapid procedures. LRB employs a nonselective period (2–5 hours) for repair of injured Listeria prior to selective-agent addition. Of 80 environmental sites positive by any method, UVM and LRB showed similar recovery rates (87.5% and 88.8%, respectively). Thus LRB provided little advantage over current procedures for use in contaminated sites. UVM was superior when used in conjunction with either rapid method. The USDA and mod...
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increased incidence of listeria species in Dairy Processing Plants having adjacent farm facilities
Journal of Food Protection, 1994Co-Authors: Todd J Pritchard, Constance M Beliveau, Kathy J Flanders, Catherine W DonnellyAbstract:The Processing environments of 30 Dairy facilities were surveyed for the presence of Listeria species. Two different primary enrichment media — University of Vermont Modified Listeria Enrichment Broth and Listeria Repair Broth — were employed to increase the probability of identifying positive samples. Samples were also tested using both an enzyme-linked immunosorbent-based (ELISA-based) assay and a gene probe assay. A total of 346 sponge samples were evaluated for the presence of Listeria. Listeria spp. were identified via one or more of the assays 122 (35.3%) times. Fifty-five of the positive samples (37.2%) contained Listeria monocytogenes and 93 (62.8%) contained Listeria innocua. Of the 30 Plants tested, 9 had a Dairy farm contiguous to the Processing facilities. Our results show that these Plants are more likely to be contaminated (9/9) than those Plants without on site Dairy farms (17/21). Analysis of the Listeria spp. results indicated that contamination was significantly higher (α = 0.1) at those...
Belgin Dogan - One of the best experts on this subject based on the ideXlab platform.
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Genetic diversity and spoilage potentials among Pseudomonas spp. isolated from fluid milk products and Dairy Processing Plants
Applied and Environmental Microbiology, 2003Co-Authors: Belgin Dogan, Kathryn J BoorAbstract:Degradation of milk components through various enzymatic activities associated with the contamination of Dairy products by Pseudomonas spp. can reduce the shelf life of processed milk. Reliable methods for differentiating among Pseudomonas spp. strains are necessary to identify and eliminate specific sources of bacterial contamination from Dairy Processing systems. To that end, we assessed the genetic diversity and Dairy product spoilage potentials among a total of 338 Pseudomonas spp. isolates from raw and pasteurized milk and from environmental samples collected from four Dairy Processing Plants. The majority of isolates were identified as P. fluorescens and P. putida by API 20 NE. A total of 42 different ribotype patterns were identified among a subset of 81 isolates. The presence of many different ribotypes within this collection indicates high genetic diversity among the isolates and suggests multiple origins of contamination within the Processing plant and in Dairy products. The extracellular enzyme activity patterns among Pseudomonas isolates appeared to be associated with ribotypes. Isolates with the same ribotype frequently had the same extracellular protease, lecithinase, and lipase activities. For example, isolates grouped in ribotype 55-S-6 had the highest extracellular protease activity, while those in ribotypes 50-S-8 and 72-S-3 had the highest extracellular lipase activities. We conclude that ribotyping provides a reliable method for differentiating Pseudomonas strains with Dairy food spoilage potential.
