Longitudinal Studies on Listeria in Smoked Fish Plants: Impact of Intervention Strategies on Contamination Patterns

2004 ◽  
Vol 67 (11) ◽  
pp. 2500-2514 ◽  
Author(s):  
VICTORIA R. LAPPI ◽  
JOANNE THIMOTHE ◽  
KENDRA KERR NIGHTINGALE ◽  
KENNETH GALL ◽  
VIRGINIA N. SCOTT ◽  
...  
Keyword(s):  
Environmental Samples ◽  
Control Strategies ◽  
Intervention Strategies ◽  
Raw Material ◽  
Processing Plant ◽  
Smoked Fish ◽  
Plant Environment ◽  
Before And After ◽  
Processing Plants ◽  
The Impact

Four ready-to-eat smoked fish plants were monitored for 2 years to study Listeria contamination patterns and the impact of plant-specific Listeria control strategies, including employee training and targeted sanitation procedures, on Listeria contamination patterns. Samples from the processing plant environment and from raw and finished product were collected monthly and tested for Listeria spp. and Listeria monocytogenes. Before implementation of intervention strategies, 19.2% of raw product samples (n = 276), 8.7% of finished product samples (n = 275), and 26.1% of environmental samples (n = 617) tested positive for Listeria spp. During and after implementation of Listeria control strategies, 19.0% of raw product samples (n = 242), 7.0% of finished product samples (n = 244), and 19.5% of environmental samples (n = 527) were positive for Listeria spp. In one of the four fish plants (plant 4), no environmental samples were positive for L. monocytogenes, and this plant was thus excluded from statistical analyses. Based on data pooled from plants 1, 2, and 3, environmental Listeria spp. prevalence was significantly lower (P < 0.05) for nonfood contact surfaces and the finished product area and for the overall core environmental samples after implementation of control strategies. Listeria prevalence for floor drains was similar before and after implementation of controls (49.6 and 54.2%, respectively). Regression analysis revealed a significant positive relationship (P < 0.05) between L. monocytogenes prevalence in the environment and in finished products before implementation of control strategies; however, this relationship was absolved by implementation of Listeria control strategies. Molecular subtyping (EcoRI ribotyping) revealed that specific L. monocytogenes ribotypes persisted in three processing plants over time. These persistent ribotypes were responsible for all six finished product contamination events detected in plant 1. Ribotype data also indicated that incoming raw material is only rarely a direct source of finished product contamination. While these data indicate that plant-specific Listeria control strategies can reduce cross-contamination and prevalence of Listeria spp. and L. monocytogenes in the plant environment, elimination of persistent L. monocytogenes strains remains a considerable challenge.

Impact of Intervention Strategies on Listeria Contamination Patterns in Crawfish Processing Plants: A Longitudinal Study†

2004 ◽  
Vol 67 (6) ◽  
pp. 1163-1169 ◽  
Author(s):  
VICTORIA R. LAPPI ◽  
JOANNE THIMOTHE ◽  
JONATHAN WALKER ◽  
JON BELL ◽  
KENNETH GALL ◽  
...  
Keyword(s):  
Raw Materials ◽  
Control Strategies ◽  
Employee Training ◽  
Raw Material ◽  
Processing Plant ◽  
Cross Contamination ◽  
Plant Environment ◽  
Processing Plants ◽  
Low Levels ◽  
The Impact

Two ready-to-eat crawfish processing plants were monitored for 2 years to study the impact of Listeria control strategies, including employee training and targeted sanitation procedures, on Listeria contamination. Environmental, raw material, and finished product samples were collected weekly during the main processing months (April to June) and tested for Listeria spp. and Listeria monocytogenes. Before implementation of control strategies (year 1), the two processing plants showed Listeria spp. prevalences of 29.5% (n = 78) in raw, whole crawfish, 5.2% (n = 155) in the processing plant environment, and 0% (n = 78) in finished products. In year 2, after plant-specific Listeria control strategies were implemented, Listeria spp. prevalence increased in raw crawfish (57.5%, n = 101), in the processing plant environment (10.8%, n = 204), and in the finished product (1.0%, n = 102). Statistical analysis showed a significant increase in Listeria spp. prevalence (P < 0.0001) and a borderline nonsignificant increase in L. monocytogenes prevalence (P = 0.097) on raw material in year 2. Borderline nonsignificant increases were also observed for Listeria spp. prevalence in environmental samples (P = 0.082). Our data showed that Listeria spp. prevalence in raw crawfish can vary significantly among seasons. However, the increased contamination prevalence for raw materials only resulted in a limited Listeria prevalence increase for the processing plant environment with extremely low levels of finished product contamination. Heat treatment of raw materials combined with Listeria control strategies to prevent cross-contamination thus appears to be effective in achieving low levels of finished product contamination, even with Listeria spp. prevalences for raw crawfish of more than 50%.

Tracking of Listeria monocytogenes in Smoked Fish Processing Plants†

2004 ◽  
Vol 67 (2) ◽  
pp. 328-341 ◽  
Author(s):  
JOANNE THIMOTHE ◽  
KENDRA KERR NIGHTINGALE ◽  
KEN GALL ◽  
VIRGINIA N. SCOTT ◽  
MARTIN WIEDMANN
Keyword(s):  
Listeria Monocytogenes ◽  
Environmental Samples ◽  
Control Strategies ◽  
Fish Processing ◽  
Smoked Fish ◽  
Plant Environment ◽  
Fish Samples ◽  
Processing Plants ◽  
Raw Fish ◽  
Contact Surfaces

Four smoked fish processing plants were used as a model system to characterize Listeria monocytogenes contamination patterns in ready-to-eat food production environments. Each of the four plants was sampled monthly for approximately 1 year. At each sampling, four to six raw fish and four to six finished product samples were collected from corresponding lots. In addition, 12 to 14 environmental sponge samples were collected several hours after the start of production at sites selected as being likely contamination sources. A total of 234 raw fish, 233 finished products, and 553 environmental samples were tested. Presumptive Listeria spp. were isolated from 16.7% of the raw fish samples, 9.0% of the finished product samples, and 27.3% of the environmental samples. L. monocytogenes was isolated from 3.8% of the raw fish samples (0 to 10%, depending on the plant), 1.3% of the finished product samples (0 to 3.3%), and 12.8% of the environmental samples (0 to 29.8%). Among the environmental samples, L. monocytogenes was found in 23.7% of the samples taken from drains, 4.8% of the samples taken from food contact surfaces, 10.4% of the samples taken from employee contact surfaces (aprons, hands, and door handles), and 12.3% of the samples taken from other nonfood contact surfaces. Listeria spp. were isolated from environmental samples in each of the four plants, whereas L. monocytogenes was not found in any of the environmental samples from one plant. Overall, the L. monocytogenes prevalence in the plant environment showed a statistically significant (P < 0.0001) positive relationship with the prevalence of this organism in finished product samples. Automated EcoRI ribotyping differentiated 15 ribotypes among the 83 L. monocytogenes isolates. For each of the three plants with L. monocytogenes–positive environmental samples, one or two ribotypes seemed to persist in the plant environment during the study period. In one plant, a specific L. monocytogenes ribotype represented 44% of the L. monocytogenes–positive environmental samples and was also responsible for one of the two finished product positives found in this plant. In another plant, a specific L. monocytogenes ribotype persisted in the raw fish handling area. However, this ribotype was never isolated from the finished product area in this plant, indicating that this operation has achieved effective separation of raw and finished product areas. Molecular subtyping methods can help identify plant-specific L. monocytogenes contamination routes and thus provide the knowledge needed to implement improved L. monocytogenes control strategies.

scholarly journals Host Ranges of Listeria-Specific Bacteriophages from the Turkey Processing Plant Environment in the United States

2008 ◽  
Vol 74 (21) ◽  
pp. 6623-6630 ◽  
Author(s):  
Jae-Won Kim ◽  
Robin M. Siletzky ◽  
Sophia Kathariou
Keyword(s):  
United States ◽  
Host Range ◽  
Environmental Samples ◽  
The United States ◽  
Host Cells ◽  
Processing Plant ◽  
Wide Host Range ◽  
Plant Environment ◽  
Processing Plants ◽  
Serotype 4B

ABSTRACT Even though at least 400 Listeria phages have been isolated from various sources, limited information is available on phages from the food processing plant environment. Phages in the processing plant environment may play critical roles in determining the Listeria population that becomes established in the plant. In this study, we pursued the isolation of Listeria-specific phages from environmental samples from four turkey processing plants in the United States. These environmental samples were also utilized to isolate Listeria spp. Twelve phages were isolated and classified into three groups in terms of their host range. Of these, nine (group 1) showed a wide host range, including multiple serotypes of Listeria monocytogenes, as well as other Listeria spp. (L. innocua, L. welshimeri, L. seeligeri, and L. ivanovii). The remaining phages mostly infected L. monocytogenes serotype 4b as well as L. innocua, L. ivanovii, and/or L. welshimeri. All but one of the strains of the serotype 4b complex (4b, 4d, 4e) from the processing plant environment could be readily infected by the wide-host-range phages isolated from the environment of the processing plants. However, many strains of other serotypes (1/2a [or 3a] and 1/2b [or 3b]), which represented the majority of L. monocytogenes strains isolated from the environmental samples, were resistant to infection by these phages. Experiments with two phage-resistant strains showed reduced phage adsorption onto the host cells. These findings suggest that phage resistance may be an important component of the ecology of L. monocytogenes in the turkey processing plants.

scholarly journals Genetic Listeria monocytogenes Types in the Pork Processing Plant Environment: From Occasional Introduction to Plausible Persistence in Harborage Sites

Pathogens ◽  
2021 ◽  
Vol 10 (6) ◽  
pp. 717
Author(s):  
Niels Demaître ◽  
Geertrui Rasschaert ◽  
Lieven De Zutter ◽  
Annemie Geeraerd ◽  
Koen De Reu
Keyword(s):  
Genetic Diversity ◽  
Environmental Samples ◽  
Genetic Characterization ◽  
Processing Plant ◽  
Pfge Analysis ◽  
Food Contact ◽  
Plant Environment ◽  
Food Contact Surfaces ◽  
Contact Surfaces ◽  
Cleaning And Disinfection

The purpose of this study was to investigate the L. monocytogenes occurrence and genetic diversity in three Belgian pork cutting plants. We specifically aim to identify harborage sites and niche locations where this pathogen might occur. A total of 868 samples were taken from a large diversity of food and non-food contact surfaces after cleaning and disinfection (C&D) and during processing. A total of 13% (110/868) of environmental samples tested positive for L. monocytogenes. When looking in more detail, zone 3 non-food contact surfaces were contaminated more often (26%; 72/278) at typical harborage sites, such as floors, drains, and cleaning materials. Food contact surfaces (zone 1) were less frequently contaminated (6%; 25/436), also after C&D. PFGE analysis exhibited low genetic heterogeneity, revealing 11 assigned clonal complexes (CC), four of which (CC8, CC9, CC31, and CC121) were predominant and widespread. Our data suggest (i) the occasional introduction and repeated contamination and/or (ii) the establishment of some persistent meat-adapted clones in all cutting plants. Further, we highlight the importance of well-designed extensive sampling programs combined with genetic characterization to help these facilities take corrective actions to prevent transfer of this pathogen from the environment to the meat.

Molecular Subtyping and Characterization of Psychrotolerant Endospore-Forming Bacteria in Two New York State Fluid Milk Processing Systems

2007 ◽  
Vol 70 (10) ◽  
pp. 2354-2364 ◽  
Author(s):  
JASON R. HUCK ◽  
NICOLE H. WOODCOCK ◽  
ROBERT D. RALYEA ◽  
KATHRYN J. BOOR
Keyword(s):  
Control Strategies ◽  
New York State ◽  
Raw Milk ◽  
Effective Control ◽  
Processing Plant ◽  
Milk Processing ◽  
High Temperature Short Time ◽  
Processing Plants ◽  
Processing Continuum ◽  
Fluid Milk

Psychrotolerant endospore-forming bacteria Bacillus and Paenibacillus spp. are important spoilage organisms in fluid milk. A recently developed rpoB subtyping method was applied to characterize the diversity and phylogenetic relationships among Bacillus and related sporeformers associated with milk processing systems. Milk samples representing the processing continuum from raw milk to pasteurized products were collected from two fluid milk processing plants, held at 6°C uptothe code date that had been established by each processing plant (i.e., either 18 or 21 days), and plated for bacterial enumeration throughout storage. Bacterial colonies selected to represent the visible diversity in colony morphology on enumeration plates were examined further. Among 385 bacterial isolates characterized, 35% were Bacillus spp., and 65% were Paenibacillus spp. A total of 92 rpoB allelic types were identified among these isolates, indicating considerable diversity among endospore-forming spoilage organisms present in fluid milk systems. Of the 92 allelic types identified, 19 were isolated from samples collected from both processing plants. The same rpoB allelic types were frequently identified in paired raw milk and packaged product samples, indicating that Bacillus and Paenibacillus spp. can enter dairy processing systems through raw milk. Certain subtypes were found exclusively in pasteurized samples, including those that were temporally independent, suggesting the possibility of in-plant sources for these spoilage organisms, including through the persistence of selected subtypes in processing plants. Development of effective control strategies for the diverse array of psychrotolerant endospore-forming organisms that currently limit the shelf lives of high-temperature short-time fluid milk products will require comprehensive, integrated efforts along the entire milk processing continuum.

Listeria monocytogenes Contamination Patterns for the Smoked Fish Processing Environment and for Raw Fish

2003 ◽  
Vol 66 (1) ◽  
pp. 52-60 ◽  
Author(s):  
ADAM D. HOFFMAN ◽  
KENNETH L. GALL ◽  
DAWN M. NORTON ◽  
MARTIN WIEDMANN
Keyword(s):  
Listeria Monocytogenes ◽  
Environmental Contamination ◽  
West Coast ◽  
Environmental Samples ◽  
Raw Materials ◽  
Processing Plant ◽  
Fish Processing ◽  
Smoked Fish ◽  
Fish Samples ◽  
Raw Fish

Reliable data on the sources of Listeria monocytogenes contamination in cold-smoked fish processing are crucial in designing effective intervention strategies. Environmental samples (n = 512) and raw fish samples (n = 315) from two smoked fish processing facilities were screened for L. monocytogenes, and all isolates were subtyped by automated ribotyping to examine the relationship between L. monocytogenes contamination from raw materials and that from environmental sites. Samples were collected over two 8-week periods in early spring and summer. The five types of raw fish tested included lake whitefish, sablefish, farm-raised Norwegian salmon, farm-raised Chilean salmon, and feral (wild-caught) salmon from the U.S. West Coast. One hundred fifteen environmental samples and 46 raw fish samples tested positive for L. monocytogenes. Prevalence values for environmental samples varied significantly (P < 0.0001) between the two plants; plant A had a prevalence value of 43.8% (112 of 256 samples), and plant B had a value of 1.2% (3 of 256 samples). For plant A, 62.5% of drain samples tested positive for L. monocytogenes, compared with 32.3% of samples collected from other environmental sites and 3.1% of samples collected from food contact surfaces. Ribotyping identified 11 subtypes present in the plant environments. Multiple subtypes, including four subtypes not found on any raw fish, were found to persist in plant A throughout the study. Contamination prevalence values for raw fish varied from 3.6% (sablefish) to 29.5% (U.S. West Coast salmon), with an average overall prevalence of 14.6%. Sixteen separate L. monocytogenes subtypes were present on raw fish, including nine that were not found in the plant environment. Our results indicate a disparity between the subtypes found on raw fish and those found in the processing environment. We thus conclude that environmental contamination is largely separate from that of incoming raw materials and includes strains persisting, possibly for years, within the plant. Operational and sanitation procedures appear to have a significant impact on environmental contamination, with both plants having similar prevalence values for raw materials but disparate contamination prevalence values for the environmental sites. We also conclude that regular L. monocytogenes testing of drains, combined with molecular subtyping of the isolates obtained, allows for efficient monitoring of persistent L. monocytogenes contamination in a processing plant.

scholarly journals Occurrence and traceability of Salmonella spp. in five Sardinian fermented sausage facilities

2019 ◽  
Vol 8 (1) ◽  
Author(s):  
Francesca Piras ◽  
Carlo Spanu ◽  
Anna Maria Mocci ◽  
Mariella Demontis ◽  
Enrico Petro Luigi De Santis ◽  
...  
Keyword(s):  
Environmental Samples ◽  
Meat Product ◽  
Raw Material ◽  
Pork Meat ◽  
Ground Meat ◽  
Salmonella Spp ◽  
Fermented Sausage ◽  
Mean Values ◽  
Ground Pork ◽  
Processing Plants

The aims of the present study were to evaluate the presence of Salmonella in five fermented sausage processing plants and their products during the production process, and to trace the possible sources of contamination. A total of 270 samples were collected: mixture of ground pork meat and fat, products at the end of acidification, sausages at the end of ripening and, during production stages, surfaces in contact with meat and surfaces not in contact with meat. For samples of ground meat, product at the end of acidification and sausages at the end of ripening, the pH and water activity (aw), were determined. All the samples were tested for the presence of Salmonella. Thirtytwo Salmonella isolates were obtained, subjected to serotyping and PFGE. The sausages at the end of ripening pH and aw mean values were 5.39±0.24 and 0.91±0.03, respectively. Salmonella was detected in three processing plants with an overall prevalence of 16.7% in food samples and 5.8% in environmental samples. Salmonella prevalence was 24% in ground meat and products at the end of acidification and was also detected in a sample of sausage at the end of ripening (2%). In environmental samples, Salmonella was detected in 6.6% of surfaces in contact with meat and 5% of surfaces not in contact with meat. Five serotypes were identified among 32 isolates: S. Derby (37.5%), S. Typhimurium and S. Rissen (both 25%), S. Give and monophasic S. Typhimurium (both 6.25%). Six different pulsotypes were obtained with PFGE. The serotypes and the PFGE pattern of the strains were specific for each facility with no overlapping between different processing plants. The same observation can be pointed out considering different sampling days for the same processing plants, thus presumably indicating the raw material (ground pork meat and fat) as the source of contamination. The detection of Salmonella in a sample of sausage at the end of ripening highlights the ability of the pathogen to survive during manufacturing process.

scholarly journals Effect of Salmonella Vaccination of Breeder Chickens on Contamination of Broiler Chicken Carcasses in Integrated Poultry Operations

2010 ◽  
Vol 76 (23) ◽  
pp. 7820-7825 ◽  
Author(s):  
Fernanda C. D�rea ◽  
Dana J. Cole ◽  
Charles Hofacre ◽  
Katherine Zamperini ◽  
Demetrius Mathis ◽  
...  
Keyword(s):  
Broiler Chicken ◽  
Vaccination Program ◽  
Broiler Chicks ◽  
Processing Plant ◽  
Broiler Meat ◽  
Serovar Typhimurium ◽  
Processing Plants ◽  
Commercial Poultry ◽  
The Difference ◽  
The Impact

ABSTRACT While measures to control carcass contamination with Salmonella at the processing plant have been implemented with some success, on-farm interventions that reduce Salmonella prevalence in meat birds entering the processing plant have not translated well on a commercial scale. We determined the impact of Salmonella vaccination on commercial poultry operations by monitoring four vaccinated and four nonvaccinated breeder (parental) chicken flocks and comparing Salmonella prevalences in these flocks and their broiler, meat bird progeny. For one poultry company, their young breeders were vaccinated by using a live-attenuated Salmonella enterica serovar Typhimurium vaccine (Megan VAC-1) followed by a killed Salmonella bacterin consisting of S. enterica serovar Berta and S. enterica serovar Kentucky. The other participating poultry company did not vaccinate their breeders or broilers. The analysis revealed that vaccinated hens had a lower prevalence of Salmonella in the ceca (38.3% versus 64.2%; P < 0.001) and the reproductive tracts (14.22% versus 51.7%; P < 0.001). We also observed a lower Salmonella prevalence in broiler chicks (18.1% versus 33.5%; P < 0.001), acquired from vaccinated breeders, when placed at the broiler farms contracted with the poultry company. Broiler chicken farms populated with chicks from vaccinated breeders also tended to have fewer environmental samples containing Salmonella (14.4% versus 30.1%; P < 0.001). There was a lower Salmonella prevalence in broilers entering the processing plants (23.4% versus 33.5%; P < 0.001) for the poultry company that utilized this Salmonella vaccination program for its breeders. Investigation of other company-associated factors did not indicate that the difference between companies could be attributed to measures other than the vaccination program.

SIMULATION OF FUGITIVE EMISSIONS OF DUST AND GASES INTO THE ATMOSPHERE DURING BLASTING OPERATIONS IN THE QUARRIES OF MINING AND PROCESSING PLANTS

2019 ◽  
Vol 12 (2) ◽  
pp. 17-25 ◽  
Author(s):  
Алла Звягинцева ◽  
Alla Zvyaginceva ◽  
Светлана Сазонова ◽  
Svetlana Sazonova ◽  
В. Кульнева ◽  
...  
Keyword(s):  
Comparative Analysis ◽  
Processing Plant ◽  
Qualitative Composition ◽  
Fugitive Emissions ◽  
Critical Situation ◽  
Harmful Emissions ◽  
Processing Plants ◽  
Harmful Substances ◽  
Definition Of ◽  
The Impact

The issues of the impact of harmful emissions from technological processes and productions in a mining and processing plant are considered. Investigations of the sources of the formation of poisonous twisted gases and dust in the atmosphere of the quarry were carried out The quantitative and qualitative composition of dust and gas emissions emitted during blasting operations is considered. The simulation of fugitive emissions of substances into the atmosphere with the definition of the main parameters of emissions during explosions. Based on the analysis of the calculations, it was revealed that the concentration of harmful substances in emissions is many times higher than the MPC, which creates a critical situation in the working areas of the plant. A comparative analysis of the project of limit-permissible emissions into the atmosphere and actual emissions at JSC Lebedinsky GOK was performed.

Colonization of a Newly Constructed Commercial Chicken Further Processing Plant with Listeria monocytogenes†

2010 ◽  
Vol 73 (2) ◽  
pp. 286-291 ◽  
Author(s):  
MARK E. BERRANG ◽  
RICHARD J. MEINERSMANN ◽  
JOSEPH F. FRANK ◽  
SCOTT R. LADELY
Keyword(s):  
Listeria Monocytogenes ◽  
Processing Plant ◽  
Monthly Basis ◽  
Raw Meat ◽  
Natural Stream ◽  
Plant Floor ◽  
Commercial Chicken ◽  
Potential Sources ◽  
Before And After ◽  
Processing Plants

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.

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