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United States Department of Agriculture

Agricultural Research Service

Related Topics

Research Project: Pathogen Reduction and Processing Parameters in Poultry Processing Systems

Location: Poultry Microbiological Safety Research

2013 Annual Report


1a.Objectives (from AD-416):
1. Develop, evaluate, and validate alternatives to current antimicrobials and sanitizers for processing poultry carcasses that meet national and international food safety standards. Specifically, alternatives to chlorine and chlorine dioxide, such as GRAS surfactants, ozone, acidified sodium chloride, and peroxyacids should be examined.

2. Characterize and evaluate poultry processing conditions associated with processed broiler carcasses that are heavily contaminated by Salmonella. This objective will include determining microbial recovery/extraction rates for poultry rinse sampling and examining survival characteristics for Salmonella serotypes that survive processing operations. Sampling should include whole carcasses that are high shedders, and mechanically-separated poultry parts.

3. Conduct studies on extrinsic factors that influence the survival and attachment of pathogenic, spoilage, and indicator microorganisms recovered from commercial poultry processing operations. These include water activity, pH, ozone, metal chelators, and organic acids.

4. Collaborate with the QSARU at Athens to develop emerging technologies for process control and correlate molecular and cultural analysis of microbial communities in poultry with process control and pathogen contamination.


1b.Approach (from AD-416):
Technologies will be developed that can be utilized by commercial processors to reduce microbial contamination associated with poultry processing. Formulations for novel sanitizers will be developed, and improved techniques utilizing sanitizers already approved for commercial use in processing will be designed. Surfactant based sanitizers used alone or in combination with non-chlorine based sanitizers will be examined as alternatives to chlorine and chlorine dioxide for decreasing microbial contamination of poultry. Additionally, poultry processing conditions associated with broiler carcasses heavily contaminated by Salmonella will be evaluated and characterized. Cross contamination during processing will be examined by studying the role of these heavily contaminated carcasses in the spread of Salmonella during processing. Furthermore, factors that influence survival and attachment of pathogenic, spoilage, and indicator microorganisms on poultry skin will be examined. Microorganisms on poultry skin will be examined utilizing Benchtop scanning electron microscopy (SEM) with SEM software and with standard microbiological methods. Finally, in collaboration with the Quality Assessment Research Unit (QARU), correlations between molecular and cultural analysis of microbial communities on poultry skin will be examined and emerging technologies for process control will be developed. Technology will be designed for use in the rapid detection and identification of pathogenic bacteria associated with poultry processing and for the characterization of microbial biofilms on broiler skin. All research goals will be achieved through an interdisciplinary team approach utilizing knowledge and skills of Unit scientists and other scientists who possess unique skills and resources that will aid in the successful completion of this project.


3.Progress Report:
Extensive progress was made on 2 of the objectives. Under Objective 3, research was conducted that led to the development of media that could be used grow Campylobacter aerobically. The development of this bacteriological media will simplify procedures for growing Campylobacter by allowing scientists to grow the bacteria under normal atmospheres instead of under artificial, microaerophilic atmospheres. Studies were also conducted to examine the ability of next generation molecular techniques to identify and enumerate bacterial pathogens in water samples taken from chill tanks of a commercial poultry processing facility. Findings from these experiments will provide new techniques for examining the spread of bacterial contamination during poultry processing. Under Objective 4, experiments were conducted to identify the ability of in-package ozone generation technology to reduce contamination of poultry meat by spoilage and pathogenic bacteria. Treatments significantly reduced bacterial contamination of the products. This technology will provide commercial processors with a new method to reduce bacterial contamination of fresh broiler meat.


4.Accomplishments
1. A medium was formulated to support aerobic growth of Campylobacter, bacterium associated with processed poultry that is recognized as a major cause of human, bacterial foodborne illnesses. Current methods for growing this pathogen require expensive equipment to produce atmospheres containing less oxygen and more carbon dioxide than normal atmospheres. Initial experiments indicated that supplementing a basal medium composed of tryptose, yeast extract, and a mineral-vitamin solution with organic acids supported the aerobic growth of this pathogen. Additional experiments indicated adding agar and sodium bicarbonate to the media enhanced aerobic growth of Campylobacter. Experiments were conducted to compare growth of the bacteria under aerobic and microaerobic conditions by inoculating the medium with Campylobacter then incubating aerobically or microaerophilically for 72 h at 37C, and enumerating the number of Campylobacter/ml recovered from the media. There was also a 5 to 6 log increase in the number of Campylobacter recovered from media supplemented with fumarate, pyruvate, agar, and NaHCO3 that was inoculated with Campylobacter spp. and incubated aerobically or microaerophilically at 37C for 72 h. Findings indicate that medium might provide an alternative to current procedures of incubating Campylobacter under microaerophilic conditions; thereby, eliminating the additional expense and training required for the use of specialized atmospheres in culturing Campylobacter.

2. Temporal study of pathogen ecology in poultry processing. ARS scientists in Athens, GA demonstrated changes in the bacterial quality of scalder tank water during commercial processing of poultry resulted in the recovery of higher levels food safety-related pathogens from the water within those tanks. Next generation molecular techniques were used to characterize and quantify the bacterial pathogens within these samples, and compare the prevalence of these pathogens to the overall bacterial community and physiochemical characteristics of the processing water. Results of this study will provide data to researchers and commercial processors on the importance of understanding the role of microbial ecology of processing water in controlling poultry food safety-related pathogens in the processing operations.

3. Due to the relatively low commercial value of eggs laid by exotic birds, little information is currently available on the production, fertility, and hatchability of these eggs. Numerous techniques have been examined to increase the fertility and hatchability of eggs of other poultry, however. Since, egg production and performance in some poultry may be improved by adding trace amounts of mineral supplements to feed provided to the poultry, an experiment was designed to test the effects of dietary, organic selenium and zinc on eggs of exotic breeder hens. One hundred twenty hens were separated into 4 treatment groups of 30 hens each, and 3 male birds were added to each group. Birds were provided test diets containing no added minerals, added selenium, added zinc, or added selenium and zinc for 21 day. Eggs were collected daily during the experiment, and the egg production, fertility, hatchability, and embryonic death of the eggs were determined. Results indicated that birds provided a diet supplemented with both selenium and zinc produced more eggs than birds provided other diets. Also, there was less embryonic death in eggs of hens provided a diet supplemented with selenium or a combination of selenium and zinc. There was no difference in the hatchability of the eggs from hens provided either diet, however. Findings of this study indicate that providing exotic birds a diet supplemented with dietary selenium and zinc can improve performance of eggs laid by these hens.

4. Use of in-package ozone generation technology to reduce poultry meat contamination. ARS scientists in Athens GA optimized a novel in-package ozonation technology to reduce bacterial contamination on chicken breast filets. Significant reductions of natural bacterial flora and surface-applied bacterial pathogens (Campylobacter jejuni) were achieved using this novel technology, and this technology is being expanded to include major food quality (Pseudomonas fluorescens) and food safety (Salmonella spp.) microorganisms. Results of this study will provide commercial processors to significantly reduce bacterial pathogens and other bacterial flora on packaged breast filets therefore increasing the quality and safety of the final product as it leaves the processing plant.

5. Development and validation of a Campylobacter genus level qPCR assay. ARS scientists in Athens, GA, developed, optimized, and validated a qPCR assay that specifically targets the Campylobacter genus from a variety of environmental samples. The assay was validated against 16 Campylobacter strains covering major and minor species and the specificity and detection limit of this assay against those strains was determined. The recovery accuracy of this assay was determined through the use of pre-defined combinations of different Campylobacter strains using both cultures and spiked environmental samples. The results of this study will provide researchers with a molecular tool, when used in conjunction with species-specific qPCR assays, to validate culture-based anecdotal information related to the distribution of Campylobacter species in different environmental samples, and provide a new tool to track Campylobacter populations within the environment.


Review Publications
Rothrock Jr, M.J., Szogi, A.A., Vanotti, M.B. 2013. Recovery of ammonia from poultry litter using flat gas permeable membranes. Journal of Waste Management. 33:1531-1538.

Hiett, K.L., Cox Jr, N.A., Rothrock Jr, M.J. 2013. Polymerase chain reaction detection of naturally occurring Campylobacter in commercial broiler chicken embryos. Poultry Science. 92(4):1134-1137.

Hiett, K.L., Rothrock Jr, M.J., Seal, B.S. 2013. Characterization of the Campylobacter jejuni cryptic plasmid pTIW94 recovered from wild birds in the southeastern United States . Plasmid Journal. 70:268-271.

Stanley, V.G., Hickerson, K., Daley, M.B., Hume, M.E., Hinton Jr, A. 2012. Single and combined effects of organic selenium and zinc on egg, fertility, hatchability, and embryonic mortality of exotic cochin hens. Agrotechnology. 2(1):106. doi:10.4172/2168-9881.1000106.

Hinton Jr, A. 2013. Aerobic growth of campylobacter in media supplemented with C3-monocarboxylates and C4-dicarboxylates. Journal of Food Protection. 76:685-690.

Sundaram, J., Park, B., Hinton Jr, A., Lawrence, K.C., Kwon, Y. 2013. Detection and differentiation of salmonella serotypes using surface enhanced Raman scattering (SERS) technique. Journal of Food Measurement & Characterization. 7(1):1-12.

Last Modified: 7/28/2014
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