Progress 09/15/02 to 09/14/07
Outputs
OUTPUTS: The objective of this research was to provide a more complete identification, characterization and assessment of significance of the risk factors associated with broiler flock Salmonella and Campylobacter status at the sequential segments of the production continuum. The study was conducted in the southern United States. The sample collection was carried out during 2003-2006. Starting from day one of broiler production cycle, 76 grow-out houses located at 38 farms were sampled prior to the placement of new flocks for rearing. Litter samples and drag swabs of the litter were obtained from the houses. Upon delivery of the flocks to be placed in the sampled houses from the hatcheries, the transport tray paper liners and chick gastrointestinal tract samples were collected. Seventy of the flocks were re-sampled at the end of rearing by whole carcass rinse, cecum, and crop samples. Sixty-six flocks raised at 33 farms were followed and re-sampled upon arrival at the processing plant by whole carcass rinse, cecum and crop samples. During processing, carcass rinses were obtained prior to the chill tank from all the 66 flocks sampled at arrival to the plant. Sixty four of those were re-sampled exiting the chill tank, at the final point of the production and processing continuum. Therefore, observation of 64 grow-out broiler flocks was completed through the entire production cycle. Bacteriological samples and risk factor information were collected on those flocks. A total of 21,671 samples were collected and analyzed for the presence of Salmonella; 5,384 were found to be positive. The isolates have been serotyped. The bacteriological and risk factor information has been partially analyzed to determine statistical associations between risk factors and the occurrence of Salmonella in broilers. The grow-out broiler flocks sampled in this study were raised by ten broiler production complexes, from two to ten flocks per complex. The complexes were owned by two individual companies. Thirty flocks were obtained from one company and 46 from the other at day one of the investigated production cycle. Both companies implemented common in the investigated region intensive commercial grow-out broiler production technologies. The sampled flocks originated from multiple production broiler breeder flocks and were hatched at seven commercial hatcheries, from five to 16 flocks per hatchery. The sampled flocks were processed at ten individual processing plants, from two to ten flocks at a plant. Therefore, it should be generally safe to assume that the findings of this study are extrapolatable to the population of grow-out broiler flocks raised under similar production scenario in the southern United States. However, certain limitations of the justifiable inference of our results to this and other broiler populations should be acknowledged. PARTICIPANTS: Dr. Robert Wills served as project director and was responsible for study design, development of survey instruments, and statistical analysis of the results. He participated in field sample collection, company relations, interpretation of results, and mentoring of graduate students. Dr. R. Hartford Bailey served as principal investigator and was responsible for preparation of materials for sample collection, laboratory analysis of samples for Salmonella, field sample collection logistics, and company relations. He participated in development of survey instruments, analysis and interpretation of results, and mentoring of graduate students. Terry Doler was a research associate and responsible for coordinating scheduling and laboratory supervision for field trial preparation and laboratory analysis. She participated in sample collection and laboratory analysis. Mary Ann Ballard was a research associate and responsible for field trial preparation. She participated in sample collection and laboratory analysis. Adam Pochocki was a laboratory manager and responsible for coordination of laboratory personnel responsibilities. Dr. Michael Rybolt was a PhD graduate student. He participated in preparation of materials for sample collection, development of laboratory protocols, sample collection, and analysis. Partner Organizations: Mississippi State University College of Veterinary Medicine; Mississippi State University College of Agriculture and Life Sciences; USDA Agricultural Research Service, Food and Feed Safety Research Unit, College Station, TX Collaborators and contacts: Dr. Allen Byrd served as collaborator and was responsible for laboratory analysis of samples for Campylobacter. He participated in the company relations, development of study design, sample collection, and interpretation of study results. Dr. Sue Ann Hubbard served as collaborator. She participated in the development of survey instruments, development of study design, interpretation of results, and mentoring of graduate students. Dr. Danny Magee served as collaborator. He participated in the development of survey instruments, development of study design, interpretation of results, and mentoring of graduate students. Dr. Anna Hood served as collaborator and participated in the outreach component of this project. Dr. Shuping Zhang served as collaborator and was responsible for serotyping all Salmonella isolates recovered from samples. Training or professional development: Dr. Michael Rybolt was a PhD graduate student. He participated in preparation of materials for sample collection, development of laboratory protocols, sample collection, and laboratory analysis. Dr. Victoria Volkova was a PhD graduate student. She participated in development of survey instruments, sample collection, laboratory analysis, data analysis and interpretation of results. Dr. Karen Dazo was a PhD graduate student. She participated in sample collection, laboratory analysis, data analysis and interpretation of results. Dr. David L. Smith was a DVM and MS graduate student. He participated in sample collection. Dr. Tyler McAlpin was a DVM and MS graduate student. He participated in sample collection. TARGET AUDIENCES: The target audience for the information and knowledge gained from the research project is the poultry industry, including poultry company personnel and poultry growers, as well as the scientific community that is devoted to improving food safety. The results of the project have been presented to Mississippi poultry companies, Mississippi State University College of Veterinary Medicine extension programs such as the Poultry Health Roundtable, National Chicken Council Technical and Regulatory Committee, the National Turkey Federation, American Association of Extension Veterinarians, Conference of Research Workers in Animal Disease, American Association of Veterinary Laboratory Diagnosticians, International Poultry Science Forum, and the USDA FSIS Office of Public Health Science. PROJECT MODIFICATIONS: The project was delayed due to an outbreak of infectious laryngeal tracheitis (ILT) in the breeder and broiler population of Mississippi from December, 2002 to March, 2003. Due to the transmissibility of the ILT virus, the Mississippi Board of Animal Health and the broiler industry instituted stringent on-farm biosecurity measures though May, 2003 to stop the spread of the disease. Consequently, we were not able to start sample collections as planned. A second major delay occurred due to Hurricane Katrina in August 2005. The hurricane and its aftermath prevented us from collecting samples from the field at full efficiency until January 2006. These delays resulted in two no-cost extensions of the project.
Impacts
An objective of this risk factor analysis was to assess relative contribution of the broiler flock and grow-out environment Salmonella status at the preceding production segments to this flock status further in the continuum. This was done by modeling interrelationships among the measurements of Salmonella in the flock and grow-out environment done at the sequential production segments by different sample types. The following was observed. (1) Broiler flock Salmonella status at the end of rearing was associated with the Salmonella contamination of the flock when delivered from the hatchery, but not with Salmonella contamination of the grow-out house at that time. (2) At arrival to the processing plant, higher proportion of the birds with Salmonella-positive ceca in the flock was associated with higher Salmonella contamination of the broilers` exterior observed in the grow-out and of the litter in the house at the end of rearing. (3) Higher exterior Salmonella contamination of broilers acquired in grow-out was positively associated with similar contamination at the time of arrival to the plant. In turn, higher exterior Salmonella contamination of the broilers delivered to the plant was associated with the increased Salmonella contamination of the carcasses entering the chill tank. (4) Proportion of the birds with Salmonella-positive crops in the broiler flocks during the grow-out was associated with Salmonella status of the flock when delivered from the hatchery. In turn, the increased proportion of the grow-out Salmonella crop-carriers was associated with a higher proportion of the crop-carriers arriving to the plants. The latter was associated with higher Salmonella contamination of the broiler carcasses at the end of processing. (5) Different sets of the risk factors were associated with Salmonella contamination of broiler carcasses prior to the chill tank and post-chill tank. A variety of the risk factors were associated with pre-chill Salmonella status of the sampled flocks, and a lesser number of factors were related to the post-chill status. The process of immersion chilling of the broiler carcasses appeared to significantly affect Salmonella contamination of the processed carcasses. (6) Frequencies of Salmonella in the litter in the grow-out house at the time of the flock's harvest and prior to the flock's placement were identified as the most significant predictors of broiler flock Salmonella status at the end of production continuum, post-chill point in processing, in this study. Therefore, it was concluded that investigation into cycling of Salmonella between broiler grow-out flocks and the litter in the houses may be a fruitful approach in reducing Salmonella contamination of the post-chill broiler carcasses. In addition to the identified risk factors, random effect of the farm, but not that of the production complex or company, was observed to significantly contribute to variability in broiler flocks Salmonella status at the end of rearing, upon arrival at the processing plant, and at the pre-chill and post-chill points in processing.
Publications
- Attila Karsi, Kevin Howe, Tasha B. Kirkpatrick, Robert W. Wills, R. Hartford Bailey, and Mark L. Lawrence. 2008. Development of bioluminescent Salmonella strains for use in food safety. BioMed Central-Microbiology 2008, 8:10.
- J. A. Byrd, R. H. Bailey, R. W. Wills, D. Nesbit. 2007. Recovery of Campylobacter from Commercial Broiler Hatchery Trayliners. Poultry Science 86(1):26-29.
- Wills, R.W.; Volkova, V.V.; Hubbard, S.A.; Magee, D.L.; Byrd, J.A.; Bailey, R.H. October 20, 2007. Interrelationships of Salmonella Status of Flock and Grow-Out Environment at Sequential Segments in Broiler Production and Processing. USAHA Proceedings, Reno, NV.
- Wills, R.W.; Bailey, R. H.; Byrd, J. A.; Hood, A. F.; Hubbard, S. A.; and Magee, D. L. July 13, 2007. Risk Factor Analysis of Salmonella and Campylobacter Flock Status in Broiler Production. NRI Epidemiological Approaches to Food Safety Principal Investigators Meeting. Washington, D.C. p 50.
- V. Volkova, K. B. R. C. Dazo, R. H. Bailey, J. A. Byrd and R. W. Wills. December 5, 2005. Intraflock Dynamics of Salmonella Contamination in Broilers 86th Annual Meeting of the Conference of Research Workers in Animal Disease. St. Louis, MO. Abstract 66, p 122.
- M.L. Rybolt, R.W. Wills, J.A. Byrd, T.P. Doler and R.H. Bailey. 2004. Comparison of Four Salmonella Isolation Techniques in Four Different Inoculated Matrices. Poultry Science 83(7):1112-1116.
- Dazo KBRC, Volkova VV, Bailey RH, Byrd JA, Wills RW. 2004. Comparison of the occurrence of Salmonella from crops, ceca and whole-carcass rinses of broilers. 85th Annual Meeting of the Conference for Research Workers in Animal Disease. Chicago, IL. Abstract 78.
- Byrd JA, Bailey RH, Wills RW, Rybolt ML, Kubena LF, Nisbet DJ. 2003. Evaluation of environmental factors on the presence of Salmonella and Campylobacter at different sites through the broiler production continuum. Poultry Science Association Annual Meeting. Milwaukee, WI.
- ML Rybolt, T Doler, R Wills, J Byrd, and R Bailey. 2003. Analysis of different sampling strategies over time for the determination of Salmonella status in broiler houses. International Poultry Science Forum. Atlanta, GA. Abstract 12.
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Progress 01/01/06 to 12/31/06
Outputs
The overall goal of this project is to identify measurable risk factors in the production process and access the impact they have on the occurrence of Salmonella and Campylobacter on broiler carcasses at the end of processing (i.e. exiting the immersion chill tank). A total of 76 broiler flocks from 38 farms were enrolled in the study; 64 of these flocks were followed through processing. Samples for bacterial isolation were collected on the day of hatching, a week before processing, and at the processing plant. Environmental, management, and production data related to the individual flocks that were followed through the production chain was also collected to provide information on potential risk factors associated with Salmonella and Campylobacter in broilers. Bacteriological samples and risk factor information has been collected on those flocks. A total of 21,671 samples were collected and analyzed for the presence of Salmonella; 5,384 were found to be positive. The
isolates have been serotyped. The bacteriological and risk factor information is currently being analyzed to determine statistical associations between risk factors and the occurrence of Salmonella in broilers.
Impacts
The ability to comply with the 1996 Pathogen Reduction and HACCP Rule is essential to the long-term viability of the U.S. poultry industry. The purpose of this project is to identify measurable risk factors in the production process and access the impact they have on the occurrence of Salmonella and Campylobacter on broiler carcasses at the end of processing.
Publications
- M.L. Rybolt, R.W. Wills, and R.H. Bailey. 2005. Use of Secondary Enrichment for Isolation of Salmonella in Naturally Contaminated Environmental Samples. Poultry Science 84:992-997.
- V. Volkova, K. B. R. C. Dazo-Galarneau, R. H. Bailey, J. A. Byrd, and R. W. Wills. December, 2006. Comparison of broiler litter sample and drag swabs to assess Salmonella contamination of broiler grow-out houses prior to placement of new flocks. 87th Annual Meeting of the Conference for Research Workers in Animal Disease. Chicago, IL. Abstract 108, p 149.
- V. Volkova, K. B. R. C. Dazo-Galarneau, R. H. Bailey, J. A. Byrd, and R. W. Wills. December, 2006. Risk factors associated with contamination of broiler grow-out houses with Salmonella prior to placement of new flocks. 87th Annual Meeting of the Conference for Research Workers in Animal Disease. Chicago, IL. Abstract 92, p. 146.
- V. Volkova, K. B. R. C. Dazo, R. H. Bailey, J. A. Byrd, and R. W. Wills. October 14, 2006. Interrelationships of Salmonella status of broiler flocks at sequential time points through the production continuum. American Association of Veterinary Laboratory Diagnosticians Annual Meeting, Minneapolis, MN.
- V. Volkova, K.B.R.C. Dazo, R. H. Bailey, J. A. Byrd, and R. W. Wills. January 23, 2006. Intraflock Dynamics of Salmonella Contamination in Broilers Throughout the Production and Processing Continuum. International Poultry Science Forum. Atlanta, GA. Abstract M44, p 15.
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