Location: Egg Safety and Quality
2007 Annual Report
Liquid egg products are sold as consumer products and utilized in the production of many bakery and convenience items. Sampling methods were developed for liquid whole egg, high whip albumen, 10% sugared yolk and 10% salted yolk due to their predominance in the egg products market. Salmonella Typhimurium was utilized to monitor sampling methods due to its known growth pattern in these products. The findings from this research will be transferred for the assessment of identified food security organisms.
Previous research conduct by this project has identified key areas of shell egg processing sanitation that need improvement. Equipment detergents and sanitizers have been explored and identified for their potential application advantages in the shell egg processing environment. Furthermore, sampling schemes have been developed for targeted bacterial populations. Subsequent studies will be conducted to determine the effectiveness of these compounds on cleaning commercial vacuum loader cups.
Seven types of retail shell eggs were examined for the presence of Enterobacteriaceae. The eggs represented the spectrum of consumer options for retail shell eggs. A total of 205 isolates were identified. The information gained from this research can be utilized for consumer education on safe handling of eggs and also by the industry to target microbial populations during processing.
Vitelline membrane strength has been identified as important for both physical and microbial egg quality. Static compression tests were conducted comparing four testing rigs. It was determined that some rigs were not as suitable for vitelline membrane strength assessment. Furthermore, the findings can be transferred to processors and breeders to assess vitelline membrane strength in a manner more targeted for their process or selection parameters.
There are regional consumer preferences for yolk color. A study was conducted to determine the variability in yolk color amongst several breeds of hens from a single laying flock. Yolk color was found to be highly variable within each strain indicating that precise control of yolk color could be difficult to achieve.
Scientists on this project participated in collaborative research with several other research units. A study was conducted to determine dielectric properties of eggs during storage and the correlation of these measurements with egg physical quality. Another project assessed shell surface sanitizers on hatching egg surface microbiology. Furthermore, assistance was provided during the development of imaging technology to assess shell eggs for micro-cracks in grading lots.
Application of post-processing shell surface sanitizers on the presence of microbial populations: Post-processing shell surface sanitizers have been required by USDA-AMS to help reduce the presence of spoilage organisms, not pathogens, on the shell surface. The recommended sanitizer approved by USDA-AMS has been 100-200 ppm chlorine. Four compounds were compared water-rinsed and unwashed eggs for their ability to reduce microbial populations associated with the shell and egg contents. Total aerobic organisms, Enterobacteriaceae, yeasts and molds and Salmonella were monitored within the shell matrix and in the egg contents during extended cold storage. The act of washing the eggs had the greatest affect on reducing microbial populations associated with the shell matrix. The various sanitizing compounds did exhibit a great change in bacterial load compared to water-rinsed washed eggs which could lead to revisiting the need for the post-processing shell sanitizing rinse requirement. This research addresses National Program 108 (Food Safety), Component 1.2 (Pathogens, Toxins, and Chemical Contaminants - Postharvest), Problem Statement 1.2.4 (Processing Strategies and Interventions).
Jones, D.R. 2007. Changes in functional characteristics and quality factors of shell eggs during long-term storage. International Journal of Poultry Science.6:157-162.
Jones, D.R., Musgrove, M.T., Caudill, A.B., Curtis, P.A. 2006. Frequency of salmonella, campylobacter, listeria, and enterobacteriaceae detection in commercially cool water washed shell eggs. Journal of Food Safety.26:264-274.
Musgrove, M.T., Jones, D.R., Northcutt, J.K., Cox Jr, N.A., Harrison, M.A., Cray, P.J., Ladely, S.R. 2006. Antimicrobial resistance in salmonella and escherichia coli isolated from commercial shell eggs. Poultry Science. 85:1665-1669.