2010 Annual Report
A study was undertaken to compare results from three modern shell quality assessment methods for both white and brown shell retail eggs. Dynamic stiffness (non-destructive measure of resonance properties of the shell) was monitored before and after exposure to a modified pressure microcrack detection system. Finally, shell strength (destructive measure of the amount of force required to crack the shell) was determined on each egg. No strong correlations existed amongst any of the measures. Dynamic stiffness readings were not altered due to eggs being exposed to the modified pressure microcrack detection system. As a portion of a study examining the role of Salmonella Enteritidis inoculation on hen health and egg production, shell quality was assessed. Dynamic stiffness, the presence of microcracks in the shells and shell static compression strength were monitored. Assessments were conducted three times a week for approximately five weeks. Complete data analysis is being conducted.
A study examining the effects of conventional cage, cage free barn and free range egg production on environmental and egg microbiology for a single strain of brown egg laying hens was initiated. The study follows the research flocks for an entire production cycle (approximately 80 weeks of age). All hens are housed on the same commercial-style research facility and receive an identical laying hen diet. Egg shells and contents, as well as environmental swabs, are enumerated for aerobic and gram negative bacteria, plus yeasts and molds. The presence of Salmonella, Campylobacter, and Listeria is also determined. The results from this study will be utilized to develop best practices for alternative egg producers to ensure product safety.
A similar study was initiated to compare three strains of brown egg laying hens housed in conventional cages, cage free barn and free range egg production systems through 80 weeks of age. Aerobic organisms, Enterobacteriaceae and yeast and molds associated with the egg shells and associated membranes are enumerated. The shell emulsions are also being assessed for the presence of Salmonella, Campylobacter and Listeria. The results of this study will be analyzed to determine if the strain of laying hen affects the microbiological characteristics of eggs from various production systems. Large and small egg producers can use this information to enhance the safety of eggs from various production environments. Preliminary experiments to analyze inoculated egg shell/membrane slurries and liquid eggs were performed using an automated system with Salmonella-coated magnetic beads. Further study is needed to determine the feasibility of the technology for egg use.
5.Significant Activities that Support Special Target Populations
Research on microbial populations associated with alternative egg production methods will assist small egg producers in the U.S. The research will provide small producers with technical information which will allow them to make informed decisions which can lead to eggs of enhanced safety and quality. Jones, D.R., Musgrove, M.T., Anderson, K.E., Thesmar, H.S. 2010. Physical Quality and Composition of Retail Shell Eggs. Poultry Science. 89:582-587
Caudill, A.B., Curtis, P.A., Anderson, K.E., Kerth, L.K., Oyarazabal, O., Jones, D.R., Musgrove, M.T. 2010. The Effects of Commercial Cool Water Washing of Shell Eggs on Haugh Unit, Vitelline Membrane Strength, Aerobic Microorganisms and Fungi. Poultry Science. 89:160-168
Jones, D.R., Lawrence, K.C., Yoon, S.C., Heitschmidt, G.W. 2010. Modified Pressure Imaging for Egg Crack Detection and Resulting Egg Quality. Poultry Science. 89:761-765.
Cox Jr, N.A., Richardson, L.J., Musgrove, M.T. 2010. Campylobacter jejuni, other campylobacters. Chapter 3 In Pathogens and Toxins in Foods: Challenges and Interventions. P.20-30.
Sommers, C.H., Sites, J.E., Musgrove, M.T. 2010. Ultraviolet light (254 NM) inactivation of pathogens on foods and stainless steel surfaces. Journal of Food Safety. 30(2):470-479.
Yoo, B., Stewart, T.E., Guard, J.Y., Musgrove, M.T., Gast, R.K., Chen, J. 2010. Selection and Characterization of Cellulose Deficient Mutants of Shiga Toxin Producing Escherichia coli. 2010. Applied and Environmental Microbiology. 73:1038-1046.