Progress 01/31/01 to 01/30/06
Outputs
Progress Report 1. What major problem or issue is being resolved and how are you resolving it (summarize project aims and objectives)? How serious is the problem? Why does it matter? The transmission of Salmonella enteritidis (SE) to humans by contaminated poultry products is an important international public health and economic problem. For more than a decade, SE has consistently been among the leading bacterial causes of food-borne human illness. Eggs are the most frequently implicated sources of human SE infections in the United States. Because egg-borne transmission of SE threatens both the safety of consumers and the ability of poultry producers to market their products, the formulation and implementation of effective control strategies for reducing the incidence of SE infections in egg-laying chickens has been identified as an urgent priority by both government and industry. The overall objective of this project is to develop improved methods for preventing,
detecting, and controlling infections of chickens with Salmonella enteritidis (SE) and the associated production of SE- contaminated eggs. The four specific goals of this research are (1) determining the processes and mechanisms by which SE infects chickens, spreads within and between flocks, and is deposited in eggs; (2) characterizing the nature of SE contamination of eggs; (3) developing more sensitive and reliable diagnostic tests for detecting SE infections of chickens and SE contamination of poultry housing environments or eggs; and (4) developing electrostatic space charging technology to diminish airborne dust and pathogens (including SE) in poultry hatching and housing facilities. This research falls under National Program 108 - Food Safety and addresses Component 1.1 of the Food Safety Action Plan (Preharvest Food Safety), with particular emphasis on addressing Problem Statements 1.1.1 (Methodology), 1.1.3 (Ecology, Host-Pathogen, and Chemical Residue Relationships), and
1.1.4 (Intervention Strategies). 2. List by year the currently approved milestones (indicators of research progress) Year 1 (FY 2001): 1 Determine the ability of an electrostatic space charge system (ESCS) to reduce biofilms on stainless steel surfaces. 2 Determine the internal locations and cell numbers at which SE is deposited inside eggs laid by experimentally infected hens. 3 Determine whether SE strains of various phage types differ in their abilities to persist and multiply in egg yolk and albumen. 4 Determine how serum antibody levels in experimentally infected hens relate to the frequency at which they lay eggs contaminated internally with SE. Year 2 (FY 2002): 1 Determine whether experimentally infected laying hens are more likely to deposit SE on the outside of the yolk membrane or inside the yolk contents, and assess the potential for SE penetration through the yolk membrane to reach the yolk contents 2 Assess the ability of a fluorescence polarization test to detect
specific antibodies in the blood of chickens infected with SE. 3 Evaluate the effectiveness of the ESCS as an intervention system for reducing airborne dust and bacteria in a broiler-breeder pullet house with a litter floor. 4 Evaluate the effectiveness of the ESCS as an intervention system for reducing SE, other pathogens, and dust in a breeder house. Year 3 (FY 2003): 1 Determine the ability of the ESCS to reduce airborne dust and ammonia levels in a full-sized broiler production house. 2 Determine the frequency, level, and location of SE deposition in egg contents for different routes of experimental inoculation of chickens. 3 Determine the ability of a fluorescence polarization test to detect specific antibodies in egg yolks produced by hens infected with SE. 4 Determine the ability of fluorescence polarization and lateral flow immunodiffusion tests to rapidly detect SE in incubated egg contents pools. 5 Determine the rate at which very small initial numbers of SE multiplied in
egg contents pools to reach levels that are consistently detectable using newly developed rapid methods. 6 Assess the effectiveness of the ESCS for inactivating specific pathogenic bacteria and bacterial spores on stainless steel surfaces. Year 4 (FY 2004): 1 Determine the ability of an experimental electrostatic sampling device to detect SE in the air of a room housing infected laying hens in individual cages. 2 Evaluate the use of various agar media for detecting airborne SE using an experimental electrostatic sampling device. 3 Determine whether repeatedly passing an SE strain through groups of chickens by oral inoculation could affect its ability to cause egg contamination. 4 Assess the ability of the ESCS to reduce SE-containing biofilms on plastic conveyor materials. Year 5 (FY 2005): 1 Determine whether incubating egg contents pools at an elevated temperature (42? C) can increase the rate of multiplication of SE sufficiently to support the detection of contamination by a rapid
lateral flow immunodiffusion method within a single day. 2 Determine whether Salmonella heidelberg isolates obtained from egg- associated human disease outbreaks are able to colonize reproductive tissues and be deposited inside eggs laid by experimentally infected hens in a manner similar to the previously documented behavior of SE. 3 Determine whether strains of SE and S. heidelberg vary in their ability to penetrate through the yolk membrane of experimentally contaminated eggs. 4 Assess the application of ESCS technology to reduce airborne contaminants and pathogens in commercial poultry production houses and biofilms in poultry processing areas. 4a List the single most significant research accomplishment during FY 2006. Colonization of reproductive organs and egg contamination by Salmonella heidelberg: Determined that four S. heidelberg strains were all able to colonize the intestinal tracts and invade to reach the livers, spleens, ovaries, and oviducts of inoculated hens, and all
four S. heidelberg strains were recovered from the interior liquid contents of eggs laid by infected hens (although less often than an S. enteritidis strain). Eggs containing S. enteritidis in their edible liquid contents have long been known to transmit disease to humans, but recent CDC reports have also linked S. heidelberg infections to eggs. Because prior research has demonstrated that S. enteritidis is deposited inside eggs after colonizing the reproductive organs (ovaries and oviducts) of laying hens, we sought to determine whether several S. heidelberg isolates (obtained from egg-associated human disease outbreaks) were also able to colonize reproductive tissues and be deposited inside eggs laid by orally infected hens. This research demonstrated that some S. heidelberg strains can colonize the reproductive tracts of laying hens and cause egg contamination in a manner similar to S. enteritidis. 4b List other significant research accomplishment(s), if any. Penetration of
Salmonella into egg yolks: Determined that all tested Salmonella strains were capable of penetrating through the vitelline membrane to reach the yolk contents (in 10% to 25% of experimentally contaminated eggs) during 24 hours of incubation at 30 deg C (86 deg. F), but variants that were obtained by isolation from infected chickens penetrated through yolk membranes at significantly higher frequencies than did their original parent strains. Although chickens infected with Salmonella do not deposit this pathogen inside egg yolks very often, bacteria from the surrounding albumen might penetrate through the membrane that surrounds the yolk, resulting in rapid and extensive Salmonella growth in the nutrient-rich interior contents of the yolk. Using a laboratory model for egg contamination, we assessed the ability of S. enteritidis and S. heidelberg strains to penetrate through the yolk membrane and multiply inside yolks. These results support an emphasis on prompt refrigeration of eggs in
Salmonella control programs to minimize the risk that pathogens will grow to higher (and more dangerous) levels after penetrating into the yolks of contaminated eggs. Elevated incubation temperature for detecting Salmonella enteritidis in eggs: Determined that incubation at an elevated temperature did not effectively support rapid Salmonella detection in liquid egg pools. Incubation at 42 deg. C did result in significantly greater multiplication of S. enteritidis after 6, 8, 10, and 12 hours than was observed at 37 deg. C, but at least 12 hours of incubation at 42 deg. were required before S. enteritidis contaminants were detected consistently by the rapid test. Because eggs contaminated with S. enteritidis typically contain very small initial numbers of bacterial cells, standard procedures for finding this pathogen in pools of liquid egg contents often include a preliminary incubation step to encourage bacterial multiplication to levels that can be consistently detected. In this
research, we determined whether small initial numbers of S. enteritidis (approximately 10 cells) would multiply fast enough in 10-egg pools incubated at 42 deg. C to allow detection of contamination by a rapid lateral flow immunodiffusion test within a single 8-hour working day. These results suggest that detection of S. enteritidis contamination within a single standard working day does not appear to be possible using current technologies for incubating and testing egg pools. Electrostatic Space Charge System (ESCS) test room and improved ESCS: An improved ESCS, installed in an exhaust dust capture enclosure on two chicken production houses, yielded reductions in bird-generated dust of up to 88% (depending on particle size). Previous research has demonstrated that ESCS technology can be highly effective for reducing levels of airborne dust and pathogens such as Salmonella enteritidis in poultry facilities. We constructed a negative-pressure, flow-controlled 720-cubic-foot test room
for evaluating ESCS performance and used results obtained in this room to configure a new ESCS design based on economical off-the-shelf components. ESCS technology offers an opportunity to achieve significant reductions in the dust-mediated airborne transmission of pathogens such as Salmonella enteritidis in commercial poultry facilities. Increased sampling period for Electrostatic Sampling Device(ESD): Developed an ESD power supply that extends the sampling period for airborne pathogens in poultry facilities to 15 hours or more, allowing the more consistent detection of low levels of pathogens. Previous research has shown that an inexpensive, portable ESD can detect airborne pathogens such as Salmonella enteritidis with a high degree of sensitivity in rooms containing infected chickens. However, the power supply for this initial ESD only allowed sampling to continue for 3 hours, thereby limiting the ability of the device to detect very low bacterial levels. Applied to exhaust air
from a poultry house, the ESD could efficiently provide a sample representative of the entire house while requiring minimal labor and expense and posing no threat to flock biosecurity. The ESD may offers a practical alternative to traditional environmental swabbing for detecting pathogens such as Salmonella enteritidis in commercial flocks. 5. Describe the major accomplishments to date and their predicted or actual impact. Determined that Salmonella enteritidis (SE) was deposited in both the yolk and albumen of eggs laid by experimentally infected hens, although the number of contaminating SE cells present in freshly laid eggs was generally relatively low. Determined that experimentally infected laying hens were more likely to deposit SE on the outside of the yolk membrane than inside the yolk contents, although SE and S. heidelberg strains penetrated through the yolk membrane to reach the yolk contents at supportive temperatures. Found that SE strains differed in their abilities to
persist and multiply in egg yolk and albumen, although these differences did not seem to be related to the phage types of the strains. Action Plan component 1.1.3; Milestones 2001-2, 2001-3, 2002-1, 2005-3. Much of this information was used (and cited as significant) by the USDA- FSIS risk assessment for shell eggs. Determined that the frequency, level, and location of SE deposition in egg contents following oral inoculation of chickens provided a more realistic simulation of naturally occurring egg contamination than occurred using intravenous or aerosol exposure. Determined that repeatedly passing an SE strain through reproductive tissues of groups of chickens by oral inoculation could increase its ability to cause egg contamination. Determined that serum antibody levels in experimentally infected hens were not consistently related to the frequency at which they laid eggs contaminated internally with SE. Determined that some S. heidelberg strains could colonize reproductive tissues
of hens and be deposited inside eggs. Action Plan component 1.1.3; Milestones 2001-4, 2003-2, 2004-3, 2005-2. Much of this information was used (and cited as significant) by the USDA-FSIS risk assessment for shell eggs. Determined that a very rapid fluorescence polarization (FP) test provided highly sensitive detection of specific antibodies in blood and egg yolk samples from chickens infected with SE, although SE infections could not always be distinguished from infections with S. typhimurium by either the FP test or by a traditional ELISA. Determined that very rapid fluorescence polarization and lateral flow immunodiffusion tests could detect SE contamination in incubated egg contents pools, but only after the pathogen was allowed to multiply to a high cell concentration. Determined that very small initial numbers of SE in egg contents pools required more than a single working day to reach levels that are consistently detectable using these newly developed rapid methods, even when
egg pools were incubated at a high temperature. Action Plan component 1.1.1; Milestones 2002-2, 2003-3, 2003-4, 2003-5, 2005-1. Information regarding egg testing methods was incorporated into the proposed FDA regulation for shell egg producers. Demonstrated that an experimental electrostatic sampling device (ESD) for airborne pathogens provided an inexpensive, efficient, and sensitive alternative to traditional methods for detecting SE in poultry housing environments and determined that proper selection of culture media was important for optimizing the sensitivity of SE detection by the ESD. Action Plan component 1.1.1; Milestones 2004-1, 2004-2. A patent application has been filed regarding this technology and it is in the process of commercialization. Demonstrated the effectiveness of the electrostatic space charge system (ESCS) as an intervention system for reducing airborne dust and bacteria in a broiler-breeder pullet house with a litter floor; SE, other pathogens, and dust in a
breeder house; and airborne dust and ammonia levels in a full-sized broiler production house. Action Plan component 1. 1.4; Milestones 2002-3, 2002-4, 2003-1, 2005-4. This technology is being field-tested for commercial potential. Established the ability of the ESCS to reduce biofilms on stainless steel surfaces and SE-containing biofilms on plastic conveyor materials. Demonstrated the effectiveness of the ESCS for inactivating specific pathogenic bacteria and bacterial spores on stainless steel surfaces. Action Plan component 1.1.4; Milestones 2001-1, 2003-6, 2004-4. This technology is being field-tested for commercial potential. 6. What science and/or technologies have been transferred and to whom? When is the science and/or technology likely to become available to the end- user (industry, farmer, other scientists)? What are the constraints, if known, to the adoption and durability of the technology products? Following discussions with an environmental engineering firm regarding
agricultural applications of the ESCS for reducing airborne dust, pathogens, odors, and ammonia, they applied for an received an exclusive license to use ESCS for this purpose. This firm presently has a tentative contract to install an ESCS in a large high-rise layer house, owned by one of the largest caged layer companies in the Midwest, on a farm which is experiencing heavy regulatory pressure by EPA to reduce dust emissions. This firm has highlighted the ESCS on their website and at the 2005 National Pork Producers Conference. The firm's biocurtain system and an ESCS have been installed together on the exhaust of two chicken production houses to determine the potential of the combined systems for reducing emissions of dust and infectious microorganisms. An infectious disease physician in Peru, leading a research project to evaluate methods for reducing airborne transmission of tuberculosis (TB) in hospital isolation rooms (using guinea pigs as sentinels), conducted performance
tests on 30 commercial ionization units and an ESCS which was provided to him under a Materials Transfer Agreement. The ESCS was the most effective ionization device and was thus selected for comparison to ultraviolet light as an intervention treatment in the TB transmission studies. Preliminary results showed that the ESCS reduced TB transmission at least as well as ultraviolet light. A small ESCS treatment chamber was loaned to a Research Food Technologist at the ARS Eastern Regional Research Center for use in experiments to determine the effectiveness of strong electrostatic charges for killing E. coli 0157 and other pathogenic microorganisms on the surface of fruit and vegetables within 7-8 inches of the discharge point. Preliminary results show bacterial reductions of 1-2 logs. This low-cost electrostatic process has previously been proven to reduce airborne and surface bacteria and spores at close range, and it may have the potential to reduce the need for chemical treatment to
reduce surface pathogens on fruit and vegetables. A prototype ESCS for use in reducing smoke in corridors and stairwells of high-rise buildings is being developed for potential commercialization by a university entrepreneurial institute. A consultant with this organization has received several inquiries from firefighter and fire safety organizations showing interest in this type of system for improving visibility for escape during fires. 7. List your most important publications in the popular press and presentations to organizations and articles written about your work. (NOTE: List your peer reviewed publications below). Presentation, "The National Poultry Improvement Plan: The Story of a Successful Salmonella Control Program." USDA-FSIS Public Meeting on Advances in Pre-Harvest Reduction of Salmonella in Poultry, Athens, Georgia, 2005. Presentation, "USDA's New Egg Safety and Quality Research Unit. "Iowa Egg Industry Symposium, Ames, Iowa, 2005.
Impacts
(N/A)
Publications
- Gast, R.K. 2005. Bacterial contamination of eggs. In Food Safety Control in the Poultry Industry. G.C. Mead, ed. Woodhead Publishing, Cambridge, UK, p. 1-20.
- Gast, R.K., Bouldin, J.G., Holt, P.S. 2005. The relationship between the duration of fecal shedding and the production of contaminated eggs by laying hens infected with strains of salmonella enteritidis and salmonella heidelberg. Avian Diseases. Vol 49:382-386.
|
Progress 10/01/04 to 09/30/05
Outputs
1. What major problem or issue is being resolved and how are you resolving it (summarize project aims and objectives)? How serious is the problem? What does it matter? The transmission of Salmonella enteritidis (SE) to humans by contaminated poultry products is an important international public health and economic problem. For more than a decade, SE has consistently been among the leading bacterial causes of food-borne human illness. Eggs are the most frequently implicated sources of human SE infections in the United States. Because egg-borne transmission of SE threatens both the safety of consumers and the ability of poultry producers to market their products, the formulation and implementation of effective control strategies for reducing the incidence of SE infections in egg-laying chickens has been identified as an urgent priority by both government and industry. The overall objective of this project is to develop improved methods for preventing, detecting, and
controlling infections of chickens with Salmonella enteritidis (SE) and the associated production of SE- contaminated eggs. The four specific goals of this research are (1) determining the processes and mechanisms by which SE infects chickens, spreads within and between flocks, and is deposited in eggs; (2) characterizing the nature of SE contamination of eggs; (3) developing more sensitive and reliable diagnostic tests for detecting SE infections of chickens and SE contamination of poultry housing environments or eggs; and (4) developing electrostatic space charging technology to diminish airborne dust and pathogens (including SE) in poultry hatching and housing facilities. This research falls under National Program 108 - Food Safety and addresses Component 1.1 of the Food Safety Action Plan (Preharvest Food Safety), with particular emphasis on addressing Problem Statements 1.1.1 (Methodology), 1.1.3 (Ecology, Host-Pathogen, and Chemical Residue Relationships), and 1.1.4
(Intervention Strategies). 2. List the milestones (indicators of progress) from your Project Plan. Year 1 (FY 2001): 1 Determine the ability of an electrostatic space charge system (ESCS) to reduce biofilms on stainless steel surfaces. 2 Determine the internal locations and cell numbers at which SE is deposited inside eggs laid by experimentally infected hens. 3 Determine whether SE strains of various phage types differ in their abilities to persist and multiply in egg yolk and albumen. 4 Determine how serum antibody levels in experimentally infected hens relate to the frequency at which they lay eggs contaminated internally with SE. Year 2 (FY 2002): 1 Determine whether experimentally infected laying hens are more likely to deposit SE on the outside of the yolk membrane or inside the yolk contents, and assess the potential for SE penetration through the yolk membrane to reach the yolk contents 2 Assess the ability of a fluorescence polarization test to detect specific antibodies
in the blood of chickens infected with SE. 3 Evaluate the effectiveness of the ESCS as an intervention system for reducing airborne dust and bacteria in a broiler-breeder pullet house with a litter floor. 4 Evaluate the effectiveness of the ESCS as an intervention system for reducing SE, other pathogens, and dust in a breeder house. Year 3 (FY 2003): 1 Determine the ability of the ESCS to reduce airborne dust and ammonia levels in a full-sized broiler production house. 2 Determine the frequency, level, and location of SE deposition in egg contents for different routes of experimental inoculation of chickens. 3 Determine the ability of a fluorescence polarization test to detect specific antibodies in egg yolks produced by hens infected with SE. 4 Determine the ability of fluorescence polarization and lateral flow immunodiffusion tests to rapidly detect SE in incubated egg contents pools. 5 Determine the rate at which very small initial numbers of SE multiplied in egg contents pools to
reach levels that are consistently detectable using newly developed rapid methods. 6 Assess the effectiveness of the ESCS for inactivating specific pathogenic bacteria and bacterial spores on stainless steel surfaces. Year 4 (FY 2004): 1 Determine the ability of an experimental electrostatic sampling device to detect SE in the air of a room housing infected laying hens in individual cages. 2 Evaluate the use of various agar media for detecting airborne SE using an experimental electrostatic sampling device. 3 Determine whether repeatedly passing an SE strain through groups of chickens by oral inoculation could affect its ability to cause egg contamination. 4 Assess the ability of the ESCS to reduce SE-containing biofilms on plastic conveyor materials. Year 5 (FY 2005): 1 Determine whether incubating egg contents pools at an elevated temperature (42 deg C) can increase the rate of multiplication of SE sufficiently to support the detection of contamination by a rapid lateral flow
immunodiffusion method within a single day. 2 Determine whether Salmonella heidelberg isolates obtained from egg- associated human disease outbreaks are able to colonize reproductive tissues and be deposited inside eggs laid by experimentally infected hens in a manner similar to the previously documented behavior of SE. 3 Determine whether strains of SE and S. heidelberg vary in their ability to penetrate through the yolk membrane of experimentally contaminated eggs. 4 Assess the application of ESCS technology to reduce airborne contaminants and pathogens in commercial poultry production houses and biofilms in poultry processing areas. 3a List the milestones that were scheduled to be addressed in FY 2005. For each milestone, indicate the status: fully met, substantially met, or not met. If not met, why. 1. Determine whether incubating egg contents pools at an elevated temperature (42 deg C) can increase the rate of multiplication of SE sufficiently to support the detection of
contamination by a rapid lateral flow immunodiffusion method within a single day. Milestone Fully Met 2. Determine whether Salmonella heidelberg isolates obtained from egg- associated human disease outbreaks are able to colonize reproductive tissues and be deposited inside eggs laid by experimentally infected hens in a manner similar to the previously documented behavior of SE. Milestone Fully Met 3. Determine whether strains of SE and S. heidelberg vary in their ability to penetrate through the yolk membrane of experimentally contaminated eggs. Milestone Fully Met 4. Assess the application of ESCS technology to reduce airborne contaminants and pathogens in commercial poultry production houses and biofilms in poultry processing areas. Milestone Fully Met 3b List the milestones that you expect to address over the next 3 years (FY 2006, 2007, and 2008). What do you expect to accomplish, year by year, over the next 3 years under each milestone? This project is currently in Peer Review
Status so there are no approved expected milestones to report at this time. These milestones will be listed in the Annual Report for the new project plan. 4a What was the single most significant accomplishment this past year? Single most significant accomplishment during FY 2005: Colonization of reproductive organs and egg contamination by Salmonella heidelberg: Determined that four S. heidelberg strains were all able to colonize the intestinal tracts and invade to reach the livers, spleens, ovaries, and oviducts of inoculated hens, and all four S. heidelberg strains were recovered from the interior liquid contents of eggs laid by infected hens (although less often than an S. enteritidis strain). Eggs containing S. enteritidis in their edible liquid contents have long been known to transmit disease to humans, but recent CDC reports have also linked S. heidelberg infections to eggs. Because prior research has demonstrated that S. enteritidis is deposited inside eggs after colonizing
the reproductive organs (ovaries and oviducts) of laying hens, we sought to determine whether several S. heidelberg isolates (obtained from egg-associated human disease outbreaks) were also able to colonize reproductive tissues and be deposited inside eggs laid by orally infected hens. This research demonstrated that some S. heidelberg strains can colonize the reproductive tracts of laying hens and cause egg contamination in a manner similar to S. enteritidis. 4b List other significant accomplishments, if any. Other significant accomplishments: Penetration of Salmonella into egg yolks: Determined that all tested Salmonella strains were capable of penetrating through the vitelline membrane to reach the yolk contents (in 10% to 25% of experimentally contaminated eggs) during 24 hours of incubation at 30 deg C (86 deg F), but variants that were obtained by isolation from infected chickens penetrated through yolk membranes at significantly higher frequencies than did their original parent
strains. Although chickens infected with Salmonella do not deposit this pathogen inside egg yolks very often, bacteria from the albumen might penetrate through the membrane that surrounds the yolk, resulting in rapid and extensive Salmonella growth in the nutrient-rich interior contents of the yolk. Using a laboratory model for egg contamination, we assessed the ability of S. enteritidis and S. heidelberg strains to penetrate through the yolk membrane and multiply inside yolks. These results support an emphasis on prompt refrigeration of eggs in Salmonella control programs to minimize the risk that pathogens will grow to higher (and more dangerous) levels after penetrating into the yolks of contaminated eggs. Elevated incubation temperature for detecting Salmonella enteritidis in eggs: Determined that incubation at an elevated temperature did not effectively support rapid Salmonella detection in liquid egg pools. Incubation at 42 deg C did result in significantly greater
multiplication of S. enteritidis after 6, 8, 10, and 12 hours than was observed at 37 deg C, but at least 12 hours of incubation at 42 deg were required before S. enteritidis contaminants were detected consistently by the rapid test. Because eggs contaminated with S. enteritidis typically contain very small initial numbers of bacterial cells, standard procedures for finding this pathogen in pools of liquid egg contents often include a preliminary incubation step to encourage bacterial multiplication to levels that can be consistently detected. In this research, we determined whether small initial numbers of S. enteritidis (approximately 10 cells) would multiply fast enough in 10-egg pools incubated at 42 deg C to allow detection of contamination by a rapid lateral flow immunodiffusion test within a single 8-hour working day. These results suggest that detection of S. enteritidis contamination within a single standard working day does not appear to be possible using current
technologies for incubating and testing egg pools. Electrostatic Space Charge System (ESCS) test room and improved ESCS: An improved ESCS, installed in an exhaust dust capture enclosure on two chicken production houses, yielded reductions in bird-generated dust of up to 88% (depending on particle size). Previous research has demonstrated that ESCS technology can be highly effective for reducing levels of airborne dust and pathogens such as Salmonella enteritidis in poultry facilities. We constructed a negative-pressure, flow-controlled 720-cubic-foot test room for evaluating ESCS performance and used results obtained in this room to configure a new ESCS design based on economical off-the-shelf components. ESCS technology offers an opportunity to achieve significant reductions in the dust-mediated airborne transmission of pathogens such as Salmonella enteritidis in commercial poultry facilities. Increased sampling period for Electrostatic Sampling Device(ESD): Developed an ESD power
supply that extends the sampling period for airborne pathogens in poultry facilities to 15 hours or more, allowing the more consistent detection of low levels of pathogens. Previous research has shown that an inexpensive, portable ESD can detect airborne pathogens such as Salmonella enteritidis with a high degree of sensitivity in rooms containing infected chickens. However, the power supply for this initial ESD only allowed sampling to continue for 3 hours, thereby limiting the ability of the device to detect very low bacterial levels. Applied to exhaust air from a poultry house, the ESD could efficiently provide a sample representative of the entire house while requiring minimal labor and expense and posing no threat to flock biosecurity. The ESD may offers a practical alternative to traditional environmental swabbing for detecting pathogens such as Salmonella enteritidis in commercial flocks. 4c List any significant activities that support special target populations. Significant
accomplishments/activities that support special target populations: None 5. Describe the major accomplishments over the life of the project, including their predicted or actual impact. Determined that Salmonella enteritidis (SE) was deposited in both the yolk and albumen of eggs laid by experimentally infected hens, although the number of contaminating SE cells present in freshly laid eggs was generally relatively low. Determined that experimentally infected laying hens were more likely to deposit SE on the outside of the yolk membrane than inside the yolk contents, although SE and S. heidelberg strains penetrated through the yolk membrane to reach the yolk contents at supportive temperatures. Found that SE strains differed in their abilities to persist and multiply in egg yolk and albumen, although these differences did not seem to be related to the phage types of the strains. Action Plan component 1.1.3; Milestones 2001-2, 2001-3, 2002-1, 2005-3. Much of this information was used
(and cited as significant) by the USDA- FSIS risk assessment for shell eggs. Determined that the frequency, level, and location of SE deposition in egg contents following oral inoculation of chickens provided a more realistic simulation of naturally occurring egg contamination than occurred using intravenous or aerosol exposure. Determined that repeatedly passing an SE strain through reproductive tissues of groups of chickens by oral inoculation could increase its ability to cause egg contamination. Determined that serum antibody levels in experimentally infected hens were not consistently related to the frequency at which they laid eggs contaminated internally with SE. Determined that some S. heidelberg strains could colonize reproductive tissues of hens and be deposited inside eggs. Action Plan component 1.1.3; Milestones 2001-4, 2003-2, 2004-3, 2005-2. Much of this information was used (and cited as significant) by the USDA-FSIS risk assessment for shell eggs. Determined that a
very rapid fluorescence polarization (FP) test provided highly sensitive detection of specific antibodies in blood and egg yolk samples from chickens infected with SE, although SE infections could not always be distinguished from infections with S. typhimurium by either the FP test or by a traditional ELISA. Determined that very rapid fluorescence polarization and lateral flow immunodiffusion tests could detect SE contamination in incubated egg contents pools, but only after the pathogen was allowed to multiply to a high cell concentration. Determined that very small initial numbers of SE in egg contents pools required more than a single working day to reach levels that are consistently detectable using these newly developed rapid methods, even when egg pools were incubated at a high temperature. Action Plan component 1.1.1; Milestones 2002-2, 2003-3, 2003-4, 2003-5, 2005-1. Information regarding egg testing methods was incorporated into the proposed FDA regulation for shell egg
producers. Demonstrated that an experimental electrostatic sampling device (ESD) for airborne pathogens provided an inexpensive, efficient, and sensitive alternative to traditional methods for detecting SE in poultry housing environments and determined that proper selection of culture media was important for optimizing the sensitivity of SE detection by the ESD. Action Plan component 1.1.1; Milestones 2004-1, 2004-2. A patent application has been filed regarding this technology and it is in the process of commercialization. Demonstrated the effectiveness of the electrostatic space charge system (ESCS) as an intervention system for reducing airborne dust and bacteria in a broiler-breeder pullet house with a litter floor; SE, other pathogens, and dust in a breeder house; and airborne dust and ammonia levels in a full-sized broiler production house. Action Plan component 1. 1.4; Milestones 2002-3, 2002-4, 2003-1, 2005-4. This technology is being field-tested for commercial potential.
Established the ability of the ESCS to reduce biofilms on stainless steel surfaces and SE-containing biofilms on plastic conveyor materials. Demonstrated the effectiveness of the ESCS for inactivating specific pathogenic bacteria and bacterial spores on stainless steel surfaces. Action Plan component 1.1.4; Milestones 2001-1, 2003-6, 2004-4. This technology is being field-tested for commercial potential. 6. What science and/or technologies have been transferred and to whom? When is the science and/or technology likely to become available to the end- user (industry, farmer, other scientists)? What are the constraints, if known, to the adoption and durability of the technology products? Following discussions with an environmental engineering firm regarding agricultural applications of the ESCS for reducing airborne dust, pathogens, odors, and ammonia, they applied for an received an exclusive license to use ESCS for this purpose. This firm presently has a tentative contract to install
an ESCS in a large high-rise layer house, owned by one of the largest caged layer companies in the Midwest, on a farm which is experiencing heavy regulatory pressure by EPA to reduce dust emissions. This firm has highlighted the ESCS on their website and at the 2005 National Pork Producers Conference. The firms biocurtain system and an ESCS have been installed together on the exhaust of two chicken production houses to determine the potential of the combined systems for reducing emissions of dust and infectious microorganisms. An infectious disease physician in Peru, leading a research project to evaluate methods for reducing airborne transmission of tuberculosis (TB) in hospital isolation rooms (using guinea pigs as sentinels), conducted performance tests on 30 commercial ionization units and an ESCS which was provided to him under a Materials Transfer Agreement. The ESCS was the most effective ionization device and was thus selected for comparison to ultraviolet light as an
intervention treatment in the TB transmission studies. Preliminary results showed that the ESCS reduced TB transmission at least as well as ultraviolet light. A small ESCS treatment chamber was loaned to a Research Food Technologist at the ARS Eastern Regional Research Center for use in experiments to determine the effectiveness of strong electrostatic charges for killing E. coli 0157 and other pathogenic microorganisms on the surface of fruit and vegetables within 7-8 inches of the discharge point. Preliminary results show bacterial reductions of 1-2 logs. This low-cost electrostatic process has previously been proven to reduce airborne and surface bacteria and spores at close range, and it may have the potential to reduce the need for chemical treatment to reduce surface pathogens on fruit and vegetables. A prototype ESCS for use in reducing smoke in corridors and stairwells of high-rise buildings is being developed for potential commercialization by a university entrepreneurial
institute. A consultant with this organization has received several inquiries from firefighter and fire safety organizations showing interest in this type of system for improving visibility for escape during fires. 7. List your most important publications in the popular press and presentations to organizations and articles written about your work. (NOTE: List your peer reviewed publications below). Presentations and publications in the popular press: Presentation, Salmonella enteritidis Infections and Egg Contamination in Chickens. Division of Foodborne and Diarrheal Diseases Seminar, Centers for Disease Control and Prevention. 2004. Atlanta, Georgia. Presentation, Detection and Control of Salmonella enteritidis in Egg- Laying Chickens. First Americana Poultry Meeting, Sponsored by Intervet International. 2004. Athens, Georgia. Presentation, Update on Research on Salmonella Deposition and Multiplication in Eggs. ARS-FSIS Food Safety Research Planning Meeting. 2005. Shepherdstown,
West Virginia. Publication, High-Efficiency, Low-Cost, Portable Electrostatic Sampler Catches Airborne Bacteria, Viruses, and Spores. Resource Magazine (Monthly publication of the American Society of Agricultural Engineers), September, 2005. Publication, Small, Portable Air Sampler Developed. Agricultural Research, October, 2005. Report, Dust Reduction System to be Licensed. http://www.ars.usda. gov/is/pr/2004/041230.htm Report, Device that Reduces Poultry Dust may also Kill Pathogens. http://nehatraining.com/news/device.html Report, Dusty Barnyards get a Cleaning. http://www.livescience. com/imageoftheday/siod_041230.html Report, BEI is Granted Exclusive USDA Technology License. http://beiagsolutions.com/June%202005%20E-News.htm Report, Dust Reduction System Licensed. http://nationalhogfarmer. com/news/dust-reduction/
Impacts
(N/A)
Publications
- Gast, R.K., Bouldin, J.G., Holt, P.S. 2004. Colonization of reproductive organs and internal contamination of eggs after experimental infection of laying hens with salmonella heidelberg and salmonella enteritidis. Avian Diseases. 48:863-869
- Gast, R.K., Holt, P.S. 2004. Incubation of Egg Contents Pools at an Elevated temperature (42 degrees Centigrade) Does Not Improve the Rapid Detection of Salmonella Enteritidis Phage Type 14b. Journal of Food Protection. 67(8):751-1754.
- Gast, R.K., Holt, P.S., Bouldin, J.G. 2004. Production of Internally Contaminated Eggs by Laying Hens Infected Experimentally With Salmonella Heidelberg. Program of American Association of Avian Pathologists Annual Meeting. p.38.
- Gast, R.K., Holt, P.S., Murase, T. 2005. Penetration of salmonella enteritidis and s. heidelberg through the vitelline membrane in an in vitro egg contamination model. Proceedings of the International Poultry Scientific Forum. 84(1):93.
- Gast, R.K., Holt, P.S., Murase, T. 2005. Penetration of salmonella enteritidis and s. heidelberg into egg yolks in an in vitro contamination model. Poultry Science. 84:621-625
- Gast, R.K., Holt, P.S. 2005. Effect of egg refrigeration on the in vitro penetration of salmonella enteritidis through the yolk membrane. Poultry Science Association. 84(1):77.
- Gast, R.K., Bouldin, J.G., Holt, P.S. 2004. Deposition of Salmonella Heidelberg Inside Eggs in Experimental Infection Studies. United States Animal Health Association Proceedings. p.42.
- Gast, R.K., Bouldin, J.G., Holt, P.S. 2005. The relationship between intestinal persistence and egg contamination for strains of salmonella enteritidis and s. heidelberg. Program of American Association of Avian Pathologists Annual Meeting. p.43
|
Progress 10/01/03 to 09/30/04
Outputs
1. What major problem or issue is being resolved and how are you resolving it (summarize project aims and objectives)? How serious is the problem? What does it matter? The transmission of SE to humans by contaminated poultry products is an important international public health and economic problem. For more than a decade, SE has consistently been among the leading bacterial causes of food-borne human illness. Eggs are the most frequently implicated sources of human SE infections in the United States. Because egg-borne transmission of SE threatens both the safety of consumers and the ability of poultry producers to market their products, the formulation and implementation of effective control strategies for reducing the incidence of SE infections in egg-laying chickens has been identified as an urgent priority by both government and industry. The overall objective of this project is to develop improved methods for preventing, detecting, and controlling infections of
chickens with Salmonella enteritidis (SE) and the associated production of SE- contaminated eggs. The four specific goals of this research are (1) determining the processes and mechanisms by which SE infects chickens, spreads within and between flocks, and is deposited in eggs; (2) characterizing the nature of SE contamination of eggs; (3) developing more sensitive and reliable diagnostic tests for detecting SE infections of chickens and SE contamination of poultry housing environments or eggs; and (4) developing electrostatic space charging technology to diminish airborne dust and pathogens (including SE) in poultry hatching and housing facilities. This research falls under National Program 108 - Food Safety and addresses specific goals 1.1.1.1 (Develop methods to detect and quantify bacterial and parasitic pathogens in the tissues and fluids of food producing animals), 1.2.1.4 (Determine reservoirs, niches, persistence, vectors, sources, and other factors favoring S. enteritidis
deposition in eggs by colonized layers), 1.3.1.2 (Determine sites of colonization, gut ecology, mucosal immunology, and pathogenesis in the animal host and factors allowing the pathogen to invade and become systemic), and 1.4.1.4 (Develop strategies to minimize pathogens, including changes in farm management, drugs, and vaccines). 2. List the milestones (indicators of progress) from your Project Plan. Year 1 (FY 2001): Determine the ability of an electrostatic space charge system (ESCS) to reduce biofilms on stainless steel surfaces. Determine the internal locations and cell numbers at which Salmonella enteritidis (SE) is deposited inside eggs laid by experimentally infected hens. Determine whether SE strains of various phage types differ in their abilities to persist and multiply in egg yolk and albumen. Determine how serum antibody levels in experimentally infected hens relate to the frequency at which they lay eggs contaminated internally with SE. Year 2 (FY 2002): Determine
whether experimentally infected laying hens are more likely to deposit SE on the outside of the yolk membrane or inside the yolk contents, and assess the potential for SE penetration through the yolk membrane to reach the yolk contents Assess the ability of a fluorescence polarization test to detect specific antibodies in the blood of chickens infected with SE. Evaluate the effectiveness of the ESCS as an intervention system for reducing airborne dust and bacteria in a broiler-breeder pullet house with a litter floor. Evaluate the effectiveness of the ESCS as an intervention system for reducing SE, other pathogens, and dust in a breeder house. Year 3 (FY 2003): Determine the ability of the ESCS to reduce airborne dust and ammonia levels in a full-sized broiler production house. Determine the frequency, level, and location of SE deposition in egg contents for different routes of experimental inoculation of chickens. Determine the ability of a fluorescence polarization test to detect
specific antibodies in egg yolks produced by hens infected with SE. Determine the ability of fluorescence polarization and lateral flow immunodiffusion tests to rapidly detect SE in incubated egg contents pools. Determine the rate at which very small initial numbers of SE multiplied in egg contents pools to reach levels that are consistently detectable using newly developed rapid methods. Assess the effectiveness of the ESCS for inactivating specific pathogenic bacteria and bacterial spores on stainless steel surfaces. Year 4 (FY 2004): Determine the ability of an experimental electrostatic sampling device to detect SE in the air of a room housing infected laying hens in individual cages. Evaluate the use of various agar media for detecting airborne SE using an experimental electrostatic sampling device. Determine whether repeatedly passing an SE strain through groups of chickens by oral inoculation could affect its ability to cause egg contamination. Assess the ability of the ESCS to
reduce SE-containing biofilms on plastic conveyor materials. Year 5 (FY 2005): Determine whether incubating egg contents pools at an elevated temperature (42 C) can increase the rate of multiplication of SE sufficiently to support the detection of contamination by a rapid lateral flow immunodiffusion method within a single day. Determine whether Salmonella heidelberg isolates obtained from egg- associated human disease outbreaks are able to colonize reproductive tissues and be deposited inside eggs laid by experimentally infected hens in a manner similar to the previously documented behavior of SE. Determine whether strains of SE and S. heidelberg vary in their ability to penetrate through the yolk membrane of experimentally contaminated eggs. Assess the application of ESCS technology to reduce airborne contaminants and pathogens in commercial poultry production houses and biofilms in poultry processing areas. 3. Milestones: A. The milestones below were scheduled to be completed
during Year 4. All milestones were completed. Determine the ability of an experimental electrostatic sampling device to detect SE in the air of a room housing infected laying hens in individual cages. Evaluate the use of various agar media for detecting airborne SE using an experimental electrostatic sampling device. Determine whether repeatedly passing an SE strain through groups of chickens by oral inoculation could affect its ability to cause egg contamination. Assess the ability of the ESCS to reduce SE-containing biofilms on plastic conveyor materials. B. The Year 5 milestones are listed below with a description of the anticipated outcomes. The current project is scheduled to be completed during FY 2005 and a new project will be developed to undergo OSQR review and subsequent implementation beginning in FY 2006. Year 5 (FY 2005): The potential for incubation of egg contents pools at an elevated temperature (42 degrees C) to increase the rate of multiplication of SE sufficiently
to support the detection of contamination by a rapid lateral flow immunodiffusion method within a single day will be determined and published. The ability of Salmonella heidelberg isolates obtained from egg- associated human disease outbreaks to colonize reproductive tissues and be deposited inside eggs laid by experimentally infected hens in a manner similar to the previously documented behavior of SE will be determined and published. The differences between strains of SE and S. heidelberg in the ability to penetrate through the yolk membrane of experimentally contaminated eggs will be determined and published. The application of ESCS technology to reduce airborne contaminants and pathogens in poultry production houses and biofilms in poultry processing areas will be explored by further cooperation with different types of commercial poultry enterprises. Assuming that the subsequent project plan continues the research along its present course, we anticipate accomplishing in: Year 6
(FY 2006): Determine the relationship between intestinal persistence of SE and S. heidelberg isolates in experimentally infected chickens and their production of internally contaminated eggs. Initiate assessment of the electrostatic sampling device for detection of airborne pathogens in commercial poultry facilities. Year 7 (FY 2007): Determine whether the location of deposition of SE in eggs laid by experimentally infected hens allows rapid penetration into and multiplication within yolks during the first few days after oviposition. Continue assessment of the electrostatic sampling device for detection of airborne pathogens in commercial poultry facilities. 4. What were the most significant accomplishments this past year? A. Single most significant accomplishment during FY 2004: Testing to detect the presence of Salmonella enteritidis (SE) in the poultry house environment has been the most common approach for determining whether laying flocks are infected and might lay contaminated
eggs. In a study conducted at the Southeast Poultry Research Laboratory in Athens, GA, a newly developed electrostatic sampling device (ESD) was evaluated for its ability to detect SE in the air of a room that housed infected laying hens in individual cages. The ESD is inexpensive, portable, simple, and easily disinfected. Air samples were positive for SE throughout the 4 weeks following inoculation of the hens, and the ESD performed similarly to a much more expensive impaction sampler. These results demonstrated that detection of airborne SE by the ESD offers an efficient, sensitive, and cost-effective alternative for detecting SE in poultry house environments. The generic technology of the ESD could also be easily adapted for diverse other applications where high efficiency air sampling for pathogens is required, in poultry and livestock production facilities, food processing facilities, hospitals, schools, nursing homes, and other public areas. B. Other significant accomplishments:
Because contaminated eggs laid by infected hens can transmit Salmonella enteritidis (SE) to humans and cause illness, detecting this pathogen in the environment of laying flocks is an important objective for protecting public health. In a study conducted at the Southeast Poultry Research Laboratory in Athens, GA, six different agar media were used in an inexpensive and portable new electrostatic sampling device (ESD) to detect SE circulating in the air of a room containing experimentally infected hens. Although all six media supported the recovery of SE from air samples for three weeks after the hens were infected, the highest frequency of SE isolation was obtained using brilliant green agar (and further improvement in SE recovery was attained by sampling with a combination of several different media). These results document the effectiveness of the ESD for detecting airborne SE in poultry environments and indicate that proper selection of culture media is important for optimizing the
sensitivity of pathogen detection by the ESD. Experimental oral inoculation is believed to closely simulate naturally occurring Salmonella enteritidis (SE) infections of chickens, but orally infected chickens often produce contaminated eggs at such low frequencies that any beneficial effects of prospective control measures cannot be measured effectively. A study at the Southeast Poultry Research Laboratory in Athens, GA assessed whether repeatedly passing an S. enteritidis strain through groups of chickens by oral inoculation could affect its ability to cause egg contamination. Passaged SE isolates recovered from reproductive tissues of hens (ovaries and oviducts) caused significantly more frequent egg contamination than did the parent strain, but passaged isolates recovered from livers and spleens did not. These results demonstrate that the passage of SE through reproductive tissues of chickens may be a useful route for improving the ability of experimental infection studies to
produce egg contamination. Non-chemical intervention approaches are needed to reduce bacterial loads and resulting cross contamination of food products on processing lines, many of which use plastic conveyor belts. In a study by researchers at the Southeast Poultry Research Laboratory in Athens, GA, an Electrostatic Space Charge System (ESCS) reduced Salmonella enteritidis (SE) biofilms on plastic conveyor materials by more than 6.7 logs. In preliminary studies, an ESCS located approximately 7 inches away was used to treat SE biofilms on small sections of plastic conveyor belt. These results suggest the ESCS may be a viable alternative or supplemental non-chemical treatment to reduce bacterial cross contamination on plastic conveyor belts in food processing plants. C. Significant accomplishments/activities that support special target populations: None. 5. Describe the major accomplishments over the life of the project, including their predicted or actual impact. Determined that
Salmonella enteritidis (SE) was deposited in both the yolk and albumen of eggs laid by experimentally infected hens, although the number of contaminating SE cells present in freshly laid eggs was generally relatively low. Determined that experimentally infected laying hens were more likely to deposit SE on the outside of the yolk membrane than inside the yolk contents, although SE penetration through the yolk membrane to reach the yolk contents occurred at supportive temperatures. Found that SE strains differed in their abilities to persist and multiply in egg yolk and albumen, although these differences did not seem to be related to the phage types of the strains. Action Plan component 1.2.1.4. Determined that the frequency, level, and location of SE deposition in egg contents following oral inoculation of chickens provided a more realistic simulation of naturally occurring egg contamination than occurred using intravenous or aerosol exposure. Determined that repeatedly passing an SE
strain through reproductive tissues of groups of chickens by oral inoculation could increase its ability to cause egg contamination. Determined that serum antibody levels in experimentally infected hens were not consistently related to the frequency at which they laid eggs contaminated internally with SE. Action Plan component 1.3. 1.2. Determined that a very rapid fluorescence polarization (FP) test provided highly sensitive detection of specific antibodies in blood and egg yolk samples from chickens infected with SE, although SE infections could not always be distinguished from infections with S. typhimurium by either the FP test or by a traditional ELISA. Action Plan component 1.1.1. 1. Determined that very rapid fluorescence polarization and lateral flow immunodiffusion tests could detect SE contamination in incubated egg contents pools, but only after the pathogen was allowed to multiply to a high cell concentration. Determined that very small initial numbers of SE in egg
contents pools required more than a single working day to reach levels that are consistently detectable using these newly developed rapid methods. Action Plan component 1.1.1.1. Demonstrated that an experimental electrostatic sampling device (ESD) for airborne pathogens provided an inexpensive, efficient, and sensitive alternative to traditional methods for detecting SE in poultry housing environments and determined that proper selection of culture media was important for optimizing the sensitivity of SE detection by the ESD. Action Plan component 1.1.1.1. Demonstrated the effectiveness of the electrostatic space charge system (ESCS) as an intervention system for reducing airborne dust and bacteria in a broiler-breeder pullet house with a litter floor; SE, other pathogens, and dust in a breeder house; and airborne dust and ammonia levels in a full-sized broiler production house. Action Plan component 1. 4.1.4. Established the ability of the ESCS to reduce biofilms on stainless steel
surfaces and SE-containing biofilms on plastic conveyor materials. Demonstrated the effectiveness of the ESCS for inactivating specific pathogenic bacteria and bacterial spores on stainless steel surfaces. Action Plan component 2.2.1.4. 6. What science and/or technologies have been transferred and to whom? When is the science and/or technology likely to become available to the end- user (industry, farmer, other scientists)? What are the constraints, if known, to the adoption and durability of the technology products? An exclusive license was given by ARS to Mainstream Engineering in March, 2004 to develop and market the electrostatic space charge system (ESCS) for air cleaning applications in HVAC systems. Baumgartner Environics, Inc. has submitted a license request to ARS to develop and market a new system for reducing dust, ammonia, odor and pathogen emissions from enclosed animal housing using a combination of their existing BioCurtain and the ESCS. A U.S. Patent was filed on
9-26-03 (U.S. Patent Application Serial Number 10/670,575, "High Efficiency Electrostatic Air Sampler") for the electrostatic sampling device (ESD). The OTT Office of ARS is also pursuing a Patent Cooperation Treaty application for the ESD to protect the patent in cooperating foreign countries and one R&D company is preparing an exclusive license request on the ESD for agricultural, hospital and other human health applications, and for bioterrorism monitoring. 7. List your most important publications in the popular press and presentations to organizations and articles written about your work. Report, "Electrostatic Dust Removal Studied." Poultry Digest Online. 2003. v. 3. www.wattnet.com/Library/ViewlibEnews.cfm?PG=1&LibNum=1139. Report, "Electrostatic System Reduces Dust and Salmonella." Poultry Times. 2004. v.51. p.21. Report, "Electrostatic Filtering Shows Success in Reducing Poultry House Dust." 2003. http://www.americanfarm.com/Poultry12-16-03g.html. Presentation, "Preventing
Salmonella enteritidis Contamination of Eggs." Unified USDA Food Safety Research Agenda Announcement Meeting. 2003. Athens, Georgia. Presentation, "Salmonella enteritidis in Eggs and Chickens: 2004 Update on USDA-ARS Research." ARS-FSIS Food Safety Research Planning Meeting. 2004. Shepherdstown, West Virginia. Presentation, "Detecting Airborne Salmonella enteritidis in the Environment of Infected Laying Hens." Department of Avian Medicine Seminar. 2004. University of Georgia. Athens, Georgia. Presentation, "Detection and Control of Salmonella enteritidis in Egg- Laying Chickens." Symposium on Egg Microbiology. Institute of Food Technologists Annual Meeting. 2004. Las Vegas, Nevada.
Impacts
(N/A)
Publications
- Gast, R.K., Mitchell, B.W., Holt, P.S. 2003. Evaluation Of Culture Media For Use In Detecting Airborne Salmonella Enteritidis In The Environment Of Experimentally Infected Laying Hens With An Electrostatic Sampling Device. United States Animal Health Association Proceedings, p.38, 2003.
- Gast, R.K., Mitchell, B.W., Holt, P.S. 2004. Detection of airborne salmonella enteritidis in the environment of experimentally infected laying hens by an electrostatic sampling device. Avian Diseases. 48:148- 154, 2004.
- Gast, R.K., Mitchell, B.W., Holt, P.S. 2004. Evaluation of Culture Media for Detecting Airborne Salmonella Enteritidis Collected With an Electrostatic Sampling Device from the Environment of Experimentally Infected Laying Hens. Poultry Science v.83 p.1106-1111, 2004.
- Lopes, V.C., Velayundhan, B.T., Halvorson, D.A., Lauer, D.C., Gast, R.K., Nagaraja, K.V. 2004. Comparison Of Methods For Differentiation Of Salmonella Enterica Serovar Enteritidis Phage Type 4 Isolates. American Journal of Veterinary Research v.65 p.538-543 2004.
- Mitchell, B.W., Richardson, J., Wilson, J., Hofacre, C. 2004. Application Of An Electrostatic Space Charge System For Dust, Ammonia And Pathogen Reduction In A Broiler Breeder House. Applied Engineering in Agriculture v. 20 p.87-93 2004.
- Waltman, D., Gast, R.K. 2003. Pathogenicity Of Two Salmonella Pullorum Isolates From Backyard Poultry. Proceedings of the Annual Meeting of the U. S. Animal Health Association Committee on Salmonella. p.25 2003.
- Gast, R.K., Mitchell, B.W., Holt, P.S. 2003. Detection Of Salmonella Enteritidis In The Environment Of Experimentally Infected Laying Hens By An Electrostatic Air Sampling Device. Proceedings of the Congress of the World Veterinary Poultry Association, p.79, 2003.
- GAST, R.K., PETTER, J.G., HOLT, P.S. EFFECT OF PRIOR SERIAL IN VIVO PASSAGE ON THE FREQUENCY OF SALMONELLA ENTERITIDIS CONTAMINATION IN EGGS FROM EXPERIMENTALLY INFECTED LAYING HENS. AVIAN DISEASES. 2003. 47:633- 639.
- Gast, R.K., Holt, P.S. 2003. Effect Of Elevated Incubation Iemperature (42 Degrees C) On The Multiplication And Rapid Detection Of Salmonella Enteritidis In Egg Contents Pools. Poultry Science, 2003.V.82(Supplement 1) Abstract, p.53-54.
|
Progress 10/01/02 to 09/30/03
Outputs
1. What major problem or issue is being resolved and how are you resolving it? The objective of this project is to develop improved methods for preventing, detecting, and controlling infections of chickens with Salmonella enteritidis (SE) and the associated production of SE- contaminated eggs. Among the specific goals of this research are determining the processes and mechanisms by which SE infects chickens, spreads within and between flocks, and is deposited in eggs; characterizing the nature of SE contamination of eggs; developing more sensitive and specific diagnostic tests for identifying SE infections of chickens and for detecting SE contamination of eggs; and developing electrostatic space charging technology to diminish airborne dust and pathogens (including SE) in poultry hatching and housing facilities. 2. How serious is the problem? Why does it matter? The transmission of SE to humans by contaminated poultry products is an important international public
health and economic problem. For more than a decade, SE has consistently been among the leading bacterial causes of food-borne human illness. Eggs are the most frequently implicated sources of human SE infections in the United States. Because egg-borne transmission of SE threatens both the safety of consumers and the ability of poultry producers to market their products, the formulation and implementation of effective control strategies for reducing the incidence of SE infections in egg-laying chickens has been identified as an urgent priority by both government and industry. 3. How does it relate to the National Program(s) and National Program Component(s) to which it has been assigned? National Program 108, Food Safety (100%) This research contributes to the Microbial Pathogens component of the Food Safety National Program by providing scientists (veterinary, food, and agricultural), regulatory agency officials, and the poultry industry with urgently needed tools to understand,
prevent, detect, and control SE infections of chickens. 4. What were the most significant accomplishments this past year? A. Single most significant accomplishment during FY 2003: Air quality in enclosed animal housing is important because it affects the emission of dust, odors, and pathogenic microorganisms and because it affects the health of animals and animal caretakers. In collaboration with BioIon, Inc., Gold Kist, and Extension Engineers and Poultry Scientists from the University of Georgia, researchers from the Southeast Poultry Research Laboratory developed, installed and tested a commercial application of the Electrostatic Space Charge System (ESCS) in a full- sized broiler production house. The ESCS reduced airborne dust in the house by 50 to 60%, but airborne ammonia from built-up litter was reduced by only about 10%. Reductions in airborne dust levels will help meet EPA clean air guidelines and, based on prior research results, should result in significant reductions in
the levels of dust-associated airborne bacteria which can be responsible for the airborne transmission of disease. B. Other significant accomplishments: Experimental infection models are essential tools for understanding how Salmonella enteritidis (SE) is deposited in eggs and for testing potential strategies to control egg-borne transmission of disease to humans. In a study conducted at the Southeast Poultry Research Laboratory, the frequency, level, and location of SE deposition in egg contents were compared for three routes of experimental inoculation of chickens (oral, aerosol, and intravenous). All three routes of inoculation with SE led to relatively low overall frequencies of production of internally contaminated eggs, generally small numbers of SE cells in contaminated eggs, and a preponderance of yolk contamination over albumen contamination. These results demonstrate that neither aerosol nor intravenous inoculation appears to offer any clear advantages over the more commonly
used oral inoculation route for the experimental simulation of naturally occurring SE contamination in eggs. Detecting infected poultry flocks is essential for controlling egg-borne transmission of Salmonella enteritidis (SE) to humans. In a study conducted at the Southeast Poultry Research Laboratory, in collaboration with Diachemix Corporation, a new fluorescence polarization test was evaluated for its ability to detect specific antibodies in egg yolks produced by hens infected with SE. When applied to egg yolk samples from experimentally inoculated laying hens, the new test detected SE infection as often as a conventional antibody assay and produced fewer misleading cross-reactions with samples from hens infected with a different type of Salmonella. These results demonstrate that this very rapid new test is an effective alternative to traditional methods for detecting SE infection in poultry. Detecting Salmonella enteritidis (SE) contamination in eggs is a critical component in
programs for reducing the transmission of this pathogen to humans. In a study conducted at the Southeast Poultry Research Laboratory, in collaboration with Diachemix Corporation, a new fluorescence polarization test was evaluated for its ability to rapidly detect SE in incubated egg contents pools. Both the fluorescence polarization test and a rapid lateral flow immunodiffusion test consistently provided positive results after egg pools were contaminated with very small numbers of SE cells and incubated to allow bacterial multiplication, but both tests were much less sensitive than standard enrichment culturing. These results demonstrate that new rapid detection methods can be useful alternatives to bacteriologic culturing for identifying eggs contaminated with SE, although these rapid methods may be less sensitive than traditional methods. Detecting Salmonella enteritidis (SE) contamination in eggs is a vital aspect of efforts to reduce the egg-borne transmission of disease to
humans. A study conducted at the Southeast Poultry Research Laboratory determined the rate at which very small initial numbers of SE multiplied in egg contents pools to reach levels that are consistently detectable using newly developed rapid methods. Very small initial numbers of SE to multiplied in egg pools to levels that the rapid methods can detect in as little as 12 hours at 37 C when the pools were supplemented with iron or concentrated enrichment media, but more time was required to reach these levels in unsupplemented pools or in pools incubated at lower temperatures. These results show that parameters such as temperature and the use of growth-promoting supplements are critical for determining whether egg pool incubation will be adequate to support the detection of SE contamination by rapid methods. Biofilms formed on poultry processing equipment by bacterial pathogens can lead to the contamination of poultry products. In collaboration with Dr. Judy Arnold (USDA-ARS, PPMQ ),
researchers at the Southeast Poultry Research Laboratory investigated the inactivation of specific pathogenic bacteria (Campylobacter jejuni, Escherichia coli, Salmonella enteritidis, Listeria monocytogenes, and Staphylococcus aureus) and bacterial spores (Bacillus stearothermophilus) on stainless steel surfaces with an Electrostatic Space Charge System (ESCS). Bacterial numbers were reduced by 99.8% and spores were reduced by 81% by exposure to the ESCS. These results suggest a strong potential for application of the ESCS concept to significantly reduce pathogenic bacteria in a processing environment. C. Significant accomplishments/activities that support special target populations: None 5. Describe the major accomplishments over the life of the project, including their predicted or actual impact. Assessed the relationship between specific types of SE isolates and their ability to cause intestinal colonization and systemic infection in chicks. Demonstrated that systemically infected
hens can produce eggs contaminated internally with SE and developed effective culture methods for detecting SE contaminants in eggs. Determined the relative likelihood for SE deposition at different locations within eggs (albumen, yolk membrane, or yolk contents) and the potential for multiplication of SE in eggs stored at different temperatures. Found that SE infection can be highly persistent in chickens and elicits a long-lasting antibody response. Developed and evaluated methods for detecting specific antibodies in serum and egg yolks from infected hens. Developed and evaluated killed vaccines for reducing the susceptibility of laying hens to SE infection. Determined that air movement can mediate the horizontal transmission of SE infection. An Electrostatic Space Charge System (ESCS) was developed and shown to be effective for removing dust and airborne bacteria (including Salmonella) in hatching cabinets and transmission cabinets. The ESCS reduced airborne SE in an isolation room
with caged layers by 95% . In broiler breeder and pullet houses, the ESCS significantly reduced dust and pathogen levels, airborne ammonia levels, and SE transmission to both growing and mature birds. At close range, the ESCS has been shown to capable of killing 98% or more of airborne and surface SE. The ESCS has been patented and an exclusive license for poultry applications has been approved. 6. What do you expect to accomplish, year by year, over the next 3 years? During FY2004, we will examine the effect of incubation temperature on the rate of multiplication of SE in egg contents pools. We will determine whether prior passage of an SE isolate through groups of laying hens can affect its ability to cause egg contamination. We will test a portable electrostatic sampling device for detecting airborne SE in poultry environments and evaluate various bacteriologic media for use in this device. We will determine the effectiveness of the Electrostatic Space Charge System (ESCS) for
inactivating pathogenic bacteria on plastic conveyor materials. We will develop and test direct transfer techniques for taking samples from the electrostatic air sampler to a PCR for rapid diagnostics of bacteria and viruses, and we will continue studies to determine the effectiveness of the ESCS for improving air quality in full sized poultry production houses. In FY2005, we will determine how egg contamination that results from infections of hens with SE differs from egg contamination caused by other types of Salmonella. We will continue to investigate the use of ESCS technology to reduce airborne contaminants and pathogens in production houses and biofilms in poultry processing areas. In FY2006, we will continue the process of developing and applying improved models and methods for producing experimental SE contamination of eggs, detecting SE contaminants in eggs, detecting specific antibodies in infected chickens, and applying ESCS technology to reduce airborne contaminants and
pathogens in production houses and biofilms in poultry processing areas. 7. What science and/or technologies have been transferred and to whom? When is the science and/or technology likely to become available to the end- user (industry, farmer, other scientists)? What are the constraints, if known, to the adoption and durability of the technology products? Negotiations are in process with an engineering firm to license the Electrostatic Space Charge System (ESCS) for air cleaning applications in buildings. They plan to develop a commercial product during the year 2004. An invention disclosure for the Electrostatic Sampling Device (ESD) was accepted by the ARS patent committee and a draft U.S. Patent Application has been prepared by the ARS Patent Advisor. There has been considerable interest in this type of device and an engineering firm has expressed an interest in licensing this technology after the patent application is filed. A draft CRADA with another company has been prepared
to develop ESCS treatment systems for reducing biofilms on plastic conveyor belts in processing areas. Two industry presentations were given to broiler producer and extension personnel to discuss ESCS applications to broiler and swine production housing. Project scientists were invited to participate in the CSREES Luncheon with the UGA Poultry Science Review Team, served on the ARS Patent Committee, elected as a Fellow of the American Society of Agricultural Engineers, selected as the ARS Federal Engineer of the Year for 2002 by the National Society of Professional Engineers, and received the American Egg Board Research Award for 2002. 8. List your most important publications in the popular press and presentations to organizations and articles written about your work. (NOTE: This does not replace your peer-reviewed publications listed below). Presentation, "Introduction." Symposium on Current and Future Prospects for Induced Molting in Laying Hens, Poultry Science Association Annual
Meeting, Newark, Delaware, 2002. Presentation, "Effect of Prior Serial in vivo Passage on the Frequency of Deposition of Salmonella enteritidis in Eggs from Experimentally Infected Laying Hens." American Veterinary Medical Association Annual Meeting, Nashville, Tennessee, 2002. Presentation, "An Overview of Research to Understand and Control Salmonella enteritidis in Chickens and Eggs." Department of Biology and Geology Seminar, University of South Carolina Aiken, Aiken, South Carolina, 2002. Presentation, "Application of an Electrostatic Space Charge System for Dust, Ammonia and Pathogen Reduction in a Broiler Breeder House." American Society of Agricultural Engineers Annual Meeting, Chicago, Illinois, 2002. Presentation, "Use of Negative Air Ionization for Reducing Bacterial Pathogens and Spores on Stainless Steel Surfaces." American Society for Microbiology Meeting, 2002. Presentation, "The Role of Testing in Programs to Control Salmonella in Poultry." Workshop on Monitoring and
Detection of Salmonella in Poultry and Poultry Environments. Sponsored by National Poultry Improvement Plan and Georgia Poultry Laboratory, Oakwood, Georgia, 2003. Presentation, "Controlling Salmonella in Poultry Flocks: ARS Research in Athens, Georgia.." ARS Workshop on Poultry Research, Orlando, Florida, 2003. Presentation, "Electrostatic Space Charge System for Air Quality Improvement in Broiler Production Houses." American Society of Agricultural Engineers Annual Meeting, Las Vegas, Nevada, 2003. Radio Interview with Joe Cornely, Director of Communications, Ohio Farm Bureau Federation, to discuss Electrostatic Space Charge System applications, December 19, 2002. Report, "Electrostatic space charge to reduce pathogens in incubators." World Poultry. 2002. v. 18 (5). p. 24. Report, "Negative air ionization for microbial control." Watt Poultry USA. October, 2002. p. 58.
Impacts
(N/A)
Publications
- Gast, R.K. Salmonella infections: introduction and Paratyphoid infections.. Saif, Y.M., editor. Iowa State University Press, Ames, IA. Diseases of Poultry, 11th edition. 2003. p.567-568 and p.583-613.
- Gast, R. K., Guard-Petter, J., Holt, P.S. Characteristics of Salmonella enteritidis contamination in eggs after oral, aerosol, and intravenous inoculation of laying hens. Avian Diseases. 2002. v.46. p.629-635.
- Gast, R.K., Guard-Petter, J., Holt, P.S. Effect of in vivo passage on the frequency of egg contamination by Salmonella enteritidis in an experimental oral infection model in laying hens. Proceedings of the Annual Meeting of the U.S. Animal Health Association Committee on Salmonella. 2002. Abstract p.40.
- GAST, R.K., HOLT, P.S. INCUBATION OF EGG CONTENTS POOLS TO SUPPORT RAPID DETECTION OF SALMONELLA ENTERICA SEROVAR ENTERITIDIS. JOURNAL OF FOOD PROTECTION. 2003. Vol. 66. No.4. p. 656-659 2003.
- GAST, R.K., HOLT, P.S., NASIR, M.S., JOLLEY, M.E., STONE, H.D. DETECTION OF SALMONELLA ENTERITIDIS IN INCUBATED POOLS OF EGG CONTENTS BY FLUORESCENCE POLARIZATION AND LATERAL FLOW IMMUNODIFFUSION. POULTRY SCIENCE. 2003. 82:687-690.
- Gast, R.K., Nasir, M.S., Jolley, M.E., Holt, P.S., Stone, H.D. Detection of experimental Salmonella enteritidis and S. typhimurium infections in laying hens by fluorescence polarization assay for egg yolk antibodies. Poultry Science. 2002. v.81. p.1128-1131.
- Richardson, J., Mitchell, B.W., Hofacre, C., Wilson, J. Effect of an electrostatic space charge system on airborne dust and subsequent potential transmission of microorganisms to broiler breeder pullets. Avian Diseases. 2003. v.47. p.128-133.
|
Progress 10/01/01 to 09/30/02
Outputs
1. What major problem or issue is being resolved and how are you resolving it? The objective of this project is to develop improved methods for preventing, detecting, and controlling infections of chickens with Salmonella enteritidis (SE) and the associated production of SE- contaminated eggs. Among the specific goals of the research are determining the processes and mechanisms by which SE infects chickens, spreads within and between flocks, and is deposited in eggs; characterizing the nature of SE contamination of eggs; developing more sensitive and specific diagnostic tests for identifying SE infections of chickens and for detecting SE contamination of eggs; and developing electrostatic space charging technology to diminish airborne dust and pathogens - including SE throughout - poultry hatching and housing facilities. 2. How serious is the problem? Why does it matter? The association between human illness caused by SE and the consumption of contaminated poultry
products is an important international public health and economic problem. In recent years, SE has been among the Salmonella serotypes most often reported to cause human illness. Eggs have been the most frequently implicated sources of human SE infections in the United States. As food-borne transmission of SE threatens both the safety of consumers and the ability of poultry producers to market their products, the formulation and implementation of effective control strategies for reducing the incidence of SE infections in chickens has been identified as an urgent priority by both government and industry. 3. How does it relate to the national Program(s) and National Program Component(s) to which it has been assigned? National Program 108, Food Safety (100%) This research contributes to the Microbial Pathogens component of the Food Safety National Program by providing scientists (veterinary, food, and agricultural), regulatory agency officials, and the poultry industry with urgently
needed tools to understand, prevent, detect, and control SE infections of chickens. 4. What was your most significant accomplishment this past year? A. Single most significant accomplishment during FY 2001: Prompt refrigeration of eggs is important for preventing small numbers of Salmonella enteritidis (SE) contaminants from multiplying to levels that could present a severe disease risk to consumers, especially if the pathogen is initially deposited inside the nutrient-rich egg yolk. A study at the Southeast Poultry Research Laboratory determined whether infected laying hens were more likely to deposit SE on the outside of the yolk membrane or inside the yolk contents, and then assessed the potential for SE penetration through the yolk membrane to reach the yolk contents. Contamination of eggs from experimentally inoculated hens occurred far more often in association with the yolk membrane than inside the yolk contents, but penetration of SE through the membrane to allow
multiplication inside the yolk occurred at a high frequency when eggs were held at warm temperatures. These results indicated that, although the deposition of SE inside egg yolks appears to occur infrequently, rapid refrigeration of eggs is still vital for preventing bacterial penetration into and multiplication within yolks. B. Other significant accomplishments: Detecting infected poultry flocks is essential for controlling egg-borne transmission of Salmonella enteritidis (SE) to humans. In a study at the Southeast Poultry Research Laboratory, a new (innovative fluorescence polarization) test was evaluated for its ability to detect antibodies in the blood of chickens infected with SE. When applied to serum samples from experimentally inoculated laying hens, the new test detected SE infection more often (and gave fewer potentially misleading cross- reactions with sera from hens infected with S. typhimurium) than a conventional antibody assay. These results demonstrate that this very
rapid new test offers an effective alternative to traditional serological methods for detecting SE infection in poultry. Airborne dust in production poultry houses has been shown to be closely related to airborne disease transmission of disease causing agents such as SE. In collaborative research with scientists at the University of Georgia, an Electrostatic Space Charge System (ESCS) was tested over a period of several weeks as an intervention system for reducing airborne dust and bacteria in a broiler-breeder pullet house with a litter floor. The ESCS reduced airborne dust by an average of 37% and airborne gram- negative bacteria by an average of 64%. Reductions in airborne dust and bacteria have been shown in previous studies with the ESCS to result in reduced SE in birds and in eggs, and interventions such as this at the breeder pullet and breeder house level are especially needed. Poultry breeder houses are known to be among the primary sources of SE and other pathogenic
bacteria which end up in the food chain. In a collaborative research study with scientists at the University of Georgia, an Electrostatic Space Charge System (ESCS) was tested over a period of several months as an intervention system for reducing breeder house SE, other pathogens, and dust. The ESCS reduced dust, ammonia, and airborne pathogenic bacteria by about 50%, and it also reduced SE in birds and growouts to 6 and 8 weeks of age of chicks hatched from eggs collected in the house. The implication of these results is that the ESCS can be an effective non-chemical intervention tool for reducing SE transmission in a breeder house and also for improving air quality by reducing dust, ammonia, and other pathogens. Available sampling devices for detecting low levels of airborne bacteria, viruses and spores are either prohibitively expensive or too complicated for practical application in poultry areas. A low-cost portable electrostatic device which has no moving parts and can use any
type of liquid or solid media has been developed at the Southeast Poultry Research Laboratory for high efficiency sampling of airborne bacteria, viruses and spores. Preliminary tests with bacteria have shown approximately 20 fold increases in plate counts compared to conventional sample plates. The device has the potential for practical application in detecting low concentration pathogens in the air, and it should be easy to adapt to a wide range of detection applications for animal or human pathogens. C. Significant accomplishments/activities that support special target populations: None. 5. Describe your major accomplishments over the life of the project, including their predicted or actual impact? Demonstrated that systemically infected hens can produce eggs contaminated internally with SE and developed effective culture methods for detecting of SE contaminants in eggs. Determined the relative likelihood for SE deposition in egg yolk or albumen and the associated opportunities
for pathogen multiplication at different storage temperatures. Found that SE infections can be highly persistent in chickens and elicits a long-lasting antibody response. Developed and evaluated methods for detecting specific antibodies in serum and egg yolks from infected hens. Developed and evaluated killed vaccines for reducing the susceptibility of laying hens to SE infection. Assessed the relationship between specific types of SE isolates and their virulence, infectivity, and invasiveness in chicks. Determined that air movement can mediate the horizontal transmission of SE infection. An ESCS was developed and shown to have effectiveness comparable to a 95% media filter for removing dust in hatching cabinets and transmission cabinets and equal or better effectiveness for removing airborne bacteria and Salmonella. The ESCS reduced airborne SE in an isolation room with caged layers approximately 95% . The kill rate of the ESCS on airborne and surface SE at close range has been shown
to be 98% or more. The ESCS has been patented and an exclusive license for poultry applications has been approved. The ESCS has been shown to reduce dust and pathogens by about 50% in experimental pullet and breeder houses, and it also reduced airborne ammonia by about 50%. SE transmission between mature hens and to growout birds was also reduced in these areas. A simple, portable electrostatic air sampling device was developed which increased collection rates by as much as 20-fold for airborne bacteria. 6. What do you expect to accomplish, year by year, over the next 3 years? During FY2003, we will continue to establish how the growth patterns of SE inside eggs affect the development and application of faster and more sensitive methods for detecting contamination. We will also evaluate how the patterns of deposition and multiplication of SE isolates in egg contents affect the probable effectiveness of proposed standards for egg refrigeration. We will also design an ESCS for full
sized production houses and test effectiveness for dust reduction and other air quality improvements. We will test the effectiveness of electrostatically- enhanced high volume air samplers for airborne pathogens including SE and avian influenza. In FY2004, we will seek to develop and apply improved models and methods for producing experimental SE contamination of eggs, detecting SE contaminants in eggs, and detecting specific antibodies in infected chickens. We will determine the effectiveness of the ESCS for inactivating bacterial spores. In other studies, we will develop and test direct transfer techniques for taking samples from the electrostatic air sampler to a PCR for rapid diagnostics. In FY2005, we will continue the process of developing and applying improved models and methods for producing experimental SE contamination of eggs, detecting SE contaminants in eggs, and detecting specific antibodies in infected chickens. We will also study the effectiveness of self-cleaning
ESCS devices in full-sized poultry production areas. 7. What technologies have been transferred and to whom? When is the technology likely to become available to the end user (industry, farmer other scientist)? What are the constraints, if known, to the adoption durability of the technology? Recent developments in methods for culturing eggs and other poultry samples to detect SE contaminants have been incorporated into the testing protocols of a national flock testing program that is still under development by FDA. BioIon, Inc. initiated patent applications for the ESCS for several foreign countries. CRADA with BioIon, Inc. on ESCS was extended to December 14, 2004 for further Research, Development, and Application of the ESCS. In collaboration with a major poultry integrator and extension engineers and poultry scientists from the University of Georgia, a prototype ESCS is being developed for dust and ammonia reduction tests in a full sized broiler production house. Summary
information on an electrostatic sampling device for airborne bacteria, viruses, and fungi was submitted for the ARS Technology Showcase scheduled for October, 2002. Detailed information on ESCS trails in commercial hatchers was given to a large poultry integrator who was interested in potential application. Twenty copies of an overview and selected reprints relating to the ESCS were sent on request to a group representing several major poultry companies for potential application of the ESCS to improve air quality in poultry housing and to reduce emissions that potentially may be regulated by the EPA Clean Air Act. 8. List your most important publications and presentations, and articles written about your work (NOTE: this does not replace your review publications which are listed below) Presentation, "Reassessing the Application of Testing for Specific Antibodies in Programs for Controlling Salmonella enteritidis in Poultry. " Department of Poultry Science Seminar, University of
Georgia, Athens, Georgia, 2001. Presentation, "Can Serology Play a Useful Role in Salmonella enteritidis Testing Programs?" Department of Avian Medicine Seminar, University of Georgia, Athens, Georgia, 2001. Presentation, "Salmonella Control in Poultry: The Example of Salmonella enteritidis." Department of Pathobiology Seminar, University of Connecticut, Storrs, Connecticut, 2002. Presentation, "The Role of Egg Culturing in Programs to Control Salmonella enteritidis in Commercial Laying Flocks." Salmonella Isolation and Identification Workshop. Sponsored by Georgia Poultry Laboratory and National Poultry Improvement Plan, Oakwood, Georgia, 2002. Presentation, "Strategic Use of Serological Testing to Detect Salmonella enteritidis in Egg-Laying Chickens." Salmonella Isolation and Identification Workshop. Sponsored by Georgia Poultry Laboratory and National Poultry Improvement Plan, Oakwood, Georgia, 2002. Presentation, "Risk Factors for Salmonella enteritidis Infection in Laying Hens."
Symposium on Minimizing the Risk of Salmonella enteritidis in Shell Eggs, International Association for Food Protection Annual Meeting, San Diego, California, 2002. Presentation, "Electrostatic space charge system for reducing pathogens and dust". Institute of Food Technologists Annual Meeting, New Orleans, LA, 2001. Presentation, "Reducing airborne dust and pathogens in a broiler breeder house". Dept. of Veterinary Medicine Seminar, Tuskegee Institute, Tuskegee, Alabama, 2002. Report, "Device that reduces poultry dust also has added benefit", Watt Poultry e-news. 2002. Report, "Device that reduces poultry dust also has added benefit", Poultry Times, 2002. Report, "Dust trapping system may also kill pathogens", Feedstuffs, http://cattlefeeder.ab.ca/manure/airqual20020204.shtml, 2002. Report, "Device that reduces poultry dust has added benefit", ARS News and Information, http://www.ars.usda.gov/is/pr/2002/020108.htm, 2002. Report, "Control of pathogens and airborne dust in poultry
houses", Food Industry Environmental Network. 2002.
Impacts
(N/A)
Publications
- Richardson, L.J., Mitchell, B. W., Wilson, J. L., Hofacre, C. L. The Effect of Electrostatic Space Charge in Reducing Dust and Microorganisms During the Rearing of Broiler Breeder Pullets. Proceedings of Southern Poultry Science Society. 2002. Abstract. p. 22-23.
- Arnold, J.W., Mitchell, B. W. Use of negative air ionization for reducing microbial contamination on stainless steel surfaces. Journal of Applied Poultry Research. 2002. v. 11. 179-186.
- Gast, R. K., Holt, P. S. Assessing the frequency and consequences of Salmonella enteritidis deposition on the egg yolk membrane. Poultry Science. 2001. v. 80. p.997-1002.
- Gast, R. K., Nasir, M. S., Jolley, M. E., Holt, P. S, Stone, H. D. Detection of experimental Salmonella enteritidis and S. typhimurium infections in laying hens by fluorescence polarization assay for egg yolk antibodies. Poultry Science. 2001. v. 80 (Suppl. 1): Abstract p. 237.
- Gast, R. K., Nasir, M. S., Jolley, M. E., Holt, P. S., Stone, H. D. Detecting antibodies to Salmonella enteritidis in serum and egg yolks from experimentally infected laying hens by fluorescence polarization. Proceedings of the Annual Meeting of the U.S. Animal Health Association Committee on Salmonella. 2001. Abstract p. 19.
- Gast, R. K., Nasir, M. S., Jolley, M. E., Holt, P. S., Stone, H. D. Serologic detection of experimental Salmonella enteritidis infections in laying hens by fluorescence polarization and enzyme immunoassay. Avian Diseases. 2002. v. 46. p. 137-142.
- Hudson, C. R., Garcia, M., Gast, R. K., Maurer, J. J. Determination of close genetic relatedness of the major Salmonella enteritidis phage types by pulsed-field gel electrophoresis and DNA sequence analysis of several Salmonella virulence genes. Avian Diseases. 2001. v. 45. p. 875-886.
- Jolley, M. E., Jolt, P., Stone, H., Nasir, M. S., Gast, R. K. The very rapid, specific detection of Salmonella enteritidis and Salmonella typhimurium cells by fluorescence polarization immunoassay (FPIA). Proceedings of the Annual Meeting of the U.S. Animal Health Association Committee on Salmonella. 2001. Abstract p. 18.
|
Progress 10/01/00 to 09/30/01
Outputs
1. What major problem or issue is being resolved and how are you resolving it?
The objective of this project is to develop improved methods for preventing, detecting, and controlling infections of chickens with Salmonella enteritidis (SE) and the associated production of SE contaminated eggs. Among the specific goals of the research are determining the processes and mechanisms by which SE infects chickens, spreads vertically and horizontally, and is deposited in eggs; characterizing the nature of SE contamination of eggs; developing more sensitive and specific diagnostic tests for identifying SE infections of chickens and for detecting SE contamination of eggs; and developing electrostatic space charging technology to diminish airborne dust and pathogens - including SE throughout - poultry hatching and housing facilities.
2. How serious is the problem? Why does it matter?
The association between human illness caused by SE and the consumption of contaminated poultry products is an important international public health and economic problem. In recent years, SE has been among the Salmonella serotypes most often reported to cause human illness. Eggs have been the most frequently implicated sources of human SE infections in the United States. As food-borne transmission of SE threatens both the safety of consumers and the ability of poultry producers to market their products, the formulation and implementation of effective control strategies for reducing the incidence of SE infections in chickens has been identified as an urgent priority by both government and industry.
3. How does it relate to the National Program(s) and National Component(s)?
National Program 108, Food Safety (100%) This research contributes to the Microbial Pathogens component of the Food Safety National Program by providing scientists (veterinary, food, and agricultural), regulatory agency officials, and the poultry industry with urgently needed tools to understand, prevent, detect, and control SE infections of chickens.
4. What were the most significant accomplishments this past year?
A. Single most significant accomplishment during FY 2001. Replicated trials conducted in a small treatment chamber showed that an electrostatic space charge system (ESCS) reduced biofilms developed on stainless steel from poultry carcass rinses by 97.3% in 2 hours and 99.8% in 3 hours. These results are comparable to those obtained by existing disinfection chemicals and indicate that the ESCS could potentially be used as a non-chemical treatment to reduce pathogens in biofilms which develop in poultry egg or meat processing areas. B. Other significant accomplishments. Because bacteria grow much more rapidly in egg yolk than in albumen, the location at which SE cells are deposited is critical for determining how quickly refrigeration must lower internal egg temperatures. After experimentally infecting groups of laying hens with SE strains of different phage types, we found SE more often in yolk than in albumen. Most contaminated eggs contained fewer than 1 SE cell per ml. These
results suggest that refrigeration standards must address the possibility that SE may sometimes be deposited in yolk. When contaminants were experimentally introduced into egg contents, we observed rapid multiplication in yolk and extended persistence in albumen for a diverse assortment of SE strains of several phage types. This suggests that egg refrigeration standards may not need to address much potential variability in growth and survival characteristics between SE strains, but preventing disease transmission by eggs requires rapid refrigeration in combination with other control measures. When we compared the levels of serum antibodies induced in experimentally infected hens to the frequency at which they laid eggs contaminated by SE, we found that the relationship between these two parameters was not very consistent. Accordingly, although antibody tests are useful tools for preliminary screening of laying flocks to detect SE infection, the magnitude of the antibody response by
individuals hens does not predict the overall risk of egg contamination associated with the flock.
5. Describe the major accomplishments over the life of the project including their predicted or actual impact.
This project provided the first definitive experimental documentation that hens systemically infected with SE could produce internally contaminated eggs. Scientists found that SE infections can be highly persistent in both chicks and hens and elicit long-lasting antibody titers. The project developed and assessed the sensitivity and predictive value of methods for detecting specific antibodies in serum and egg yolks from infected hens. The project developed effective and practical bacteriological methods for consistently detecting very small numbers of SE contaminants in eggs. Efficient killed vaccines were developed and evaluated for reducing the susceptibility of laying hens to SE infection. Studies assessed the relationship between phage type of SE isolates and their virulence, infectivity, and invasiveness in chicks. One scientist determined that air movement can mediate the horizontal transmission of SE infection. An ESCS was developed under a CRADA to reduce airborne dust and
microorganisms in hatching cabinets. The ESCS has been shown to have effectiveness comparable to a 95% media filter for removing dust in laboratory experiments in hatching cabinets and transmission cabinets and equal or better effectiveness for removing airborne bacteria and Salmonella. The ESCS reduced airborne SE in an isolation room with caged layers approximately 95%. The kill rate of the ESCS on airborne and surface SE at close range has been shown to be 98% or more. The ESCS has been patented and an exclusive license for poultry applications has been approved with BioIon, Inc. to manufacture and distribute the system.
6. What do you expect to accomplish, year by year, over the next 3 years?
During FY2002, we will establish how the growth patterns of SE inside eggs affects the development and application of faster methods for detecting contamination. During this year we also will study the effectiveness of the ESCS for pathogen reduction in egg rooms and upsize pathogen reduction hatchery studies to include followup of chicks from ionizer treated hatching cabinets to full-sized production houses. We will also determine the effectiveness of the ESCS for reducing pathogens and airborne disease transmission in a small scale breeder house and investigate the mechanism by which ionization inactivates SE. Effectiveness of the ESCS for reduction of biofilms in large open areas will be determined. For FY2003, we will evaluate how the patterns of deposition and multiplication of SE isolates in egg contents affects the probable effectiveness of proposed standards for egg refrigeration. We will also design an ESCS for full sized breeder houses and test effectiveness for pathogen
and dust reduction. In FY2004, we will seek to develop and apply improved models and methods for producing experimental SE contamination of eggs, detecting SE contaminants in eggs, and detecting specific antibodies in infected chickens. We will also study the effectiveness of self-cleaning ESCS devices in poultry production areas and test the effectiveness of electrostatically-enhanced high volume air samplers for airborne pathogens.
7. What science and/or technologies have been transferred and to whom? When is the science and/or technology likely to become available to the end user (industry, farmer, other scientists)? What are the constraints if known, to the adoption & durability of the technology product?
Completed commercial hatcher tests of ESCS with two commercial poultry production compnies. CRADA partner initiated patent applications for the ESCS for several foreign countries. Participated in the 2001 International Poultry and Egg Exhibition January 17-19, 2000 where the ESCS and related posters were displayed in a commercial exhibit for hatchery equipment. Recent developments in methods for culturing eggs and other poultry samples to detect SE contaminants have been incorporated into the testing protocols of a national flock testing program under development by FDA.
8. List your most important publications in the popular press (no abstracts) and presentations to non-scientific organizations and articles written about your work (NOTE: this does not replace your peer-reviewed publications which are listed below)
Report, "Electrostatic space charge system for reducing airborne pathogens and dust", FLC Awards Page, http://flc2.federallabs.org/servlet/newContentObjServlet?LinkCoArID=2001- 05-29-15-58-08-480-mchambers&CoArRegion=National&parentID=2001-05-24-13-47- 50-770-mchambers, May 2001. Report, "Researchers honored for transferring technologies." ARS News and Information, http://www.ars.usda.gov/is/pr/2001/010501.htm, May 2001. Presentation, "Reducing airborne dust and bacteria in the hatchery." Georgia International Poultry Course, Athens, Georgia 2001. Presentation, "Pathogen reduction in poultry housing." Nebraska Poultry Industries, Columbus, Nebraska, 2001. Presentation, "Epidemiology and ecology of Salmonella enteritidis in poultry: general issues and research needs." Public Meeting on Salmonella Enteritidis Research, Sponsored by U. S. Food and Drug Administration, Atlanta, Georgia, 2000. Presentation, "The evolving application of egg culturing for detecting Salmonella enteritidis
infection in laying flocks." Salmonella Isolation and Identification Workshop. Sponsored by Georgia Poultry Laboratory and National Poultry Improvement Plan, Oakwood, Georgia, 2001.
Impacts
(N/A)
Publications
- Gast, R.K., Petter, J.G., Holt, P.S. Frequency and location of Salmonella enteritidis contamination in eggs associated with various routes of experimental infection of laying hens. Program of the annual meeting of the American Association of Avian Pathologists. 2001. p. 21. Abstract.
- Gast, R.K., Holt, P.S. Deposition of phage type 4 and 13a Salmonella enteritidis strains in the yolk and albumen of eggs laid by experimentally infected hens. Avian Diseases. 2000. v. 44. p.706-710.
- Gast, R.K., Holt, P.S. Multiplication in egg yolk and survival in egg albumen of Salmonella enterica serotype Enteritidis strains of phage types 4, 8, 13a, and 14b. Journal of Food Protection. 2001. v. 64. p.865-868.
- Mitchell, B.W. Emerging technology electrostatic space charge system for pathogen reduction. Institute of Food Technology Abstract. http://ift.confex.com/ift/2001/techprogram/paper_6385.htm. 2001.
- Mitchell, B.W., Holt, P.S., Seo, K.H. Effectiveness of electrostatic space charge for reducing dust in a caged layer room. Journal of Applied Poultry Research. 2000. v. 9. p.292-296.
- Ricke, S.C., Birkhold, S.G., Gast, R.K. Eggs and egg products. Downes, F. P., Ito, K., editors. American Public Health Association, Washington, DC. Compendium of methods for the microbiological examination of foods, 4th edition. 2001. p.473-481.
- Seo, K.H., Mitchell, B.W., Holt, P.S., Gast, R.K. Bactericidal effects of negative air ions on airborne and surface Salmonella enteritidis from an artificially generated aerosol. Journal of Food Protection. 2001. v. 64. p.113-116.
- Gast, R.K., Holt, P.S. The relationship between the magnitude of the specific antibody response to experimental Salmonella enteritidis infection in laying hens and their production of contaminated eggs. Avian Diseases. 2001. v. 45. p.425-431.
- Gast, R.K., Nadir, M.S., Jolly, M.E., Holt, P.S., Stone, H.D. Serological detection of experimental Salmonella enteritidis infections in laying hens by fluorescence polarization and enzyme immunoassay. Poultry Science. 2001. v. 80. p.1044. (Abstract).
|
|