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United States Department of Agriculture

Agricultural Research Service

2011 Annual Report

1a.Objectives (from AD-416)
There are 4 objectives for the project emphasizing food safety, quality, and security of shell eggs and egg products. First, to evaluate post-processing sanitizers and sanitizing technologies for their benefits to the microbiological safety and quality of shell eggs. Second, to develop technologies and/or techniques to improve processing plant sanitation practices. Third, to develop, evaluate and validate rapid detection methods for pathogens and toxins (for example: Staphylococcus aureus and staphylococcal enterotoxins, Listeria, Vibrio and Yersinia species) which could compromise food security in egg products, including liquid egg. Fourth, to examine differences in microbial flora associated with the eggs from alternative agriculture practices.

1b.Approach (from AD-416)
The five year project plan for the Egg Safety, Quality and Security ARS Research Program will address issues of concern for the shell egg and egg products industry, regulatory personnel, allied industry and consumers. Emphasis will be placed on determining the role post-processing shell surface sanitizers play in product safety and quality. Novel compounds as well as application technologies will be examined. Furthermore, processing plant sanitation will be more thoroughly assessed to determine points where interventions could increase sanitation program effectiveness. Procedures will include evaluating equipment surfaces for improved cleaning methods. This will be of particular interest for both regulators and the industry with the advent of new processing regulations. With the recent importance of food security, rapid detection techniques for potential biological terror pathogens that could be introduced into liquid egg product will be evaluated. Through this objective, a greater understanding of intercepting potential agricultural threats will be gleaned. This project plan encompasses a large body of work that will result in safer, higher quality shell eggs and egg products for the consumer. Agricultural production practices have become more diverse to meet consumer demands. The microbial flora of eggs from alternative production will be compared to traditional production to gain a better understanding of their potential impact on egg safety.

3.Progress Report
Over the course of this project, great strides were achieved to enhance the safety and quality of shell eggs and egg products reaching consumers. In the shell egg processing facility, effective cleaning and sanitation strategies for microbial growth niches in the processing line (such as vacuum loader cups and packer-head brushes) were developed. The intervention techniques were transferred to industry. Additional work examined the formation of bio-films on processing surfaces. The use of varying compounds as post-processing shell surface sanitizers was explored for microbiological and physical quality implications.

Bulk liquid egg sampling methods for the detection of human pathogens were developed. Detection methodologies for Salmonella and Yersinia were also explored and growth rates in a wide variety of egg products were determined.

Through collaborative efforts with other ARS scientists in Athens, GA a modified-pressure micro-crack detection system for eggs was developed. Research has determined the micro-crack detection system to be more accurate than professional egg graders in detecting very small cracks in eggs. Also, exposure to the modified-pressure micro-crack detection system does not have a negative effect on quality or Salmonella contamination of eggs exposed to the system. Furthermore, research has confirmed the system does not induce cracking in eggs, even in eggs with very poor quality shells. Additional research confirms the system does not alter dynamic properties of the shell. Exposing broiler hatching eggs to the system does not alter hatchability. A patent has been awarded for the system. Extensive efforts have been made to transfer all research findings to customers and have resulted in great interest in the technology from various factions of the egg industry.

The implications of alternative laying hen housing on environmental and egg microbiology have been examined through three, 2 yr life-cycle commercial-style production studies. The prevalence of Salmonella, Campylobacter, and Listeria as well as the level of aerobic organisms, coliforms/Enterobacteriaceae, and yeasts and molds were monitored. In the first production study, conventional cage and free range production were compared. In the second study, conventional cage, free range, and cage-free production were compared. In a third study, three strains of laying hens were monitored in conventional cage, free range, and cage-free production. Customers are utilizing the data to modernize processing requirements, production monitoring, husbandry practices, and regulations. Extensive efforts have been made to report the results to a wide variety of customers. This has been a high impact area of research resulting in the formation of a new project solely focused on food safety and quality of various laying hen production practices.

This project was replaced by 6612-41420-019-00D Intervention and Processing Strategies for Food-borne Pathogens in Shell Eggs and 6612-32420-001-00D Microbiological, Immunological, and Product Quality Consequences of Housing Laying Hens in Production Systems.

1. Modified pressure crack detection system doesn't lead to increased microbial penetration. The modified pressure microcrack detection system for shell eggs developed by ARS scientists in Athens, GA has been shown to be highly accurate in detecting very small cracks in egg shells. These very small cracks present a food safety hazard in that microorganisms can more easily enter the egg contents when the shell is impaired. Research has determined that exposing eggs to the modified pressure environment of the microcrack detection system doesn't enhance penetration of Salmonella Enteritidis into the egg contents, nor does the system lead to cross-contamination between eggs. Therefore, screening shell eggs with the microcrack system will lead to safer eggs reaching United States consumers without impairing egg quality.

Review Publications
Musgrove, M.T., Jones, D.R., Shaw, J.D., Sheppard, M., Harrison, M.A. 2010. Enterobacteriaceae and related organisms isolated from nest run cart shelves in commercial shell egg processing facilities. Poultry Science. 88:2113-2117.

Jones, D.R., Lawrence, K.C., Yoon, S.C., Heitschmidt, G.W. 2011. Salmonella contamination in shell eggs exposed to modified pressure imaging for microcrack detection. Poultry Science. 90:1616-1619.

Jones, D.R., Anderson, K.E., Musgrove, M.T. 2011. Comparison of environmental and egg microbiology associated with conventional and free range laying hen management. Poultry Science. 90:2063-2068.

Gurtler, J., Marks, H.M., Jones, D.R., Bailey, R., Bauer, N.E. 2011. Thermal inactivation kinetics of heat-resistant Salmonella Enteritidis and Oranienberg in 10% salted liquid egg yolk. Journal of Food Protection. 74(6):882-892.

Last Modified: 9/2/2015
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