Page Banner

United States Department of Agriculture

Agricultural Research Service

Related Topics

Research Project: Microbiological and Product Quality Consequences of Housing Laying Hens in Production Systems

Location: Egg Safety and Quality

2012 Annual Report


1a.Objectives (from AD-416):
Develop processing and storage options for small flock egg producers to ensure egg safety and quality. Evaluate the role of various production and management systems on the detection, transmission, and persistence of Salmonella spp. in eggs and the surrounding production environment (e.g. flocks and house contamination). Evaluate the role of various production and management systems on the immune parameters of chickens and whether the immune responses can be used as an intervention approach. In conjuction, this project will evaluate the immune response as a potential marker of pathogen load or as a marker for critical points for interventions.


1b.Approach (from AD-416):
Egg safety and quality issues often initiate in production and storage before entering the processing facility. There is a need for a farm-to-fork approach to product safety and quality, especially in light of new federal regulations and increased interest in alternative housing systems to replace housing hens in cages. Research will serve today’s fully integrated and streamlined egg industry most effectively if it covers the full scope of egg production to processing. Additionally, strategies to assist small flock egg producers enhance product safety and quality will also be developed. These goals will be accomplished by assessing the role of production systems on naturally occurring flora and pathogens in and on shell eggs, evaluating the effects of federally mandated storage conditions on the microbial and physical quality of eggs from various production systems, and developing processing and storage options for small flock egg producers to ensure egg safety and quality. The poultry house environment plays a highly significant role in Salmonella infections of laying flocks. This research will determine how different production systems for housing laying hens affect the transmission and persistence of experimentally introduced Salmonella infection or house contamination and the associated frequency and nature of egg contamination. It will also determine how different production systems affect the detection of Salmonella in laying flocks and their housing environment, and evaluate the performance of testing methodologies for detecting S. Enteritidis and other Salmonella spp. in flocks and eggs from different production systems to develop rapid, sensitive, and cost-effective testing strategies. Eliciting a strong immune response against Salmonella spp. is crucial for preventing or reducing flock infections and ultimately Salmonella-contaminated eggs. Stress caused by raising hens in different production systems could compromise the response and exacerbate the Salmonella problem. This research will focus on the development of systemic and mucosal immunity by hens housed under different production conditions in response to infection or vaccination. Information regarding the strengths and weaknesses of the different systems with regards to development of Salmonella immunity will be determined enabling industry to design effective production facilities which address both the welfare and immunocompetence of the hens.


3.Progress Report:
Implications of high and low free range production paddock stocking density on egg and environmental microbiology. Quantification of aerobic, Enterobacteriaceae, and yeast and mold populations; as well as prevalence of Salmonella, Campylobacter, and Listeria are examined. Hens have either 12.7 or 44.5 sq ft/hen of paddock space. This study will conclude FY13.

Impact of sustainable grazing in organic egg production on egg and environmental microbiology. Organic laying hens were split into two grazing regimens: dedicated pasture or behind an organic dairy herd. Aerobic, Enterobacteriaceae, and yeast and mold populations are enumerated. The incidence of Salmonella, Campylobacter, and Listeria are also monitored. This study will conclude FY13.

Frequency and magnitude of internal organ colonization following exposure of laying hens to different oral doses of Salmonella Enteritidis. Determined exposing laying hens to quantitatively different oral doses of S. Enteritidis resulted in significant differences in both the initial post-inoculation frequency of fecal shedding and the duration of this shedding over the course of the experiment.

Development of a disease-containment facility for studying the effects of housing systems on Salmonella Enteritidis infections in egg-laying hens. A facility containing single-bird research cages was redesigned and renovated by the installation of conventional multiple-bird laying cages and enriched multiple-bird cages (furnished with perches and enclosed nesting areas; incorporating more floor space per hen), providing a more accurate simulation of commercially relevant housing systems.

Environmental Salmonella status of small backyard laying flocks in Delaware. A collaborative study with Delaware State University was initiated to determine the prevalence of Salmonella in ranging, small flock egg production in Delaware throughout the year. Grass samples are sent to ARS for Salmonella assessment. This study will conclude FY13.

Comparing egg quality from hens housed in various commercial production systems. The first production flock comparing conventional and enriched cage, as well as aviary systems in commercial egg production was completed. Egg production for the second flock has begun. Monthly, eggs are monitored for shell and egg component physical quality attributes. Quarterly, a sample of eggs is washed and refrigerated to determine the rate of egg quality decline over 12 weeks.

Effect of alternative in-shell pasteurization methods on egg quality. Egg quality analyses were conducted to supplement alternative egg pasteurization method development by scientists at the Eastern Regional Research Center. Control and experimentally pasteurized eggs were shipped to the laboratory for physical quality determinations.

Automatic adjusting LED lighting for egg microcrack detection. Research was expanded to develop automatically adjusting LED lighting for previously developed modified pressure egg microcrack detection technology. Research will continue to determine the appropriate lighting parameters and programming of software for integrated adjustments.


4.Accomplishments
1. Effects of commercial conventional cage, enriched cage, and aviary production on egg quality. ARS researcher in Athens, Georgia compared the quality of eggs from multiple commercial housing systems throughout a complete production flock. Each system had positive and negative egg quality impacts. U.S. egg producers can utilize the information produced from this study to make informed decisions as to the best production systems for their various egg markets while ensuring egg quality. Until this study, there were no complete comparisons of U.S. alternative commercial egg production systems and resulting egg quality.

2. Frequency and persistence of fecal shedding following exposure of laying hens to different oral doses of Salmonella Enteritidis. ARS researchers in Athens, Georgia determined that exposing laying hens to quantitatively increasing oral doses of Salmonella Enteritidis (ranging from 104 to 108 cells) resulted in corresponding increases in both the initial post-inoculation frequency of fecal shedding and the duration of this shedding over the course of the experiment. The results of this study indicate that higher oral exposure doses can significantly increase fecal shedding of S. Enteritidis into the laying house by infected hens. Accordingly, the probability of detecting infection by environmental testing protocols which depend on fecal shedding may be relatively low when hens in a flock are exposed to low doses of S. Enteritidis.


Review Publications
Gast, R.K., Guraya, R., Holt, P.S. 2011. Frequency and persistence of fecal shedding following exposure of laying hens to different oral doses of Salmonella enteritidi. International Journal of Poultry Science. 10:750-756.

Gast, R.K., Guraya, R., Guard, J.Y., Holt, P.S. 2010. Multiplication of Salmonella Enteritidis in egg yolks after inoculation outside, on, and inside vitelline membranes and storage at different temperatures. Journal of Food Protection. 73:1902-1906.

Gast, R.K., Guraya, R., Guard, J.Y., Holt, P.S. 2011. The relationship between the numbers of Salmonella Enteritidis, Salmonella Heidelberg, or Salmonella Hadar colonizing reproductive tissues of experimentally infected laying hens and deposition inside eggs. Avian Diseases. 55:243-247.

Yoon, S.C., Lawrence, K.C., Jones, D.R., Heitschmidt, G.W. 2012. Improved modified pressure imaging and software for egg micro-crack detection and egg quality grading. Applied Engineering in Agriculture. 28(2):283-293.

Lawrence, K.C., Jones, D.R., Yoon, S.C., Heitschmidt, G.W., Anderson, K.E. 2011. Improved hairline crack detector and poor shell-quality eggs. Applied Engineering in Agriculture. 28(1):153-158.

Chmielewski, R.A., Day, J.M., Spatz, S.J., Yu, Q., Gast, R.K., Zsak, L., Swayne, D.E. 2011. Thermal inactivation of avian viral pathogens in an effluent treatment system within a biosafety level 2 and 3 enhanced facility. Applied Biosafety. 16(4):206-217.

Jones, D.R., Anderson, K.E., Guard, J.Y. 2012. Prevalence of coliforms, Salmonella, Listeria, and Campylobacter associated with eggs and the environment of conventional cage and free range egg production. Poultry Science. 91:1195-1202.

Anderson, K.E., Jones, D.R. 2012. Effect of genetic selection on growth parameters and tonic immobility in Leghorn pullets. Poultry Science. 91:765-770.

Yoon, S.C., Lawrence, K.C., Jones, D.R., Heitschmidt, G.W., Park, B. 2012. Motion compensated image processing and optimal parameters for egg crack detection using modified pressure. Sensing and Instrumentation for Food Quality and Safety. 5(5):172-184.

Last Modified: 9/10/2014
Footer Content Back to Top of Page