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United States Department of Agriculture

Agricultural Research Service

Research Project: EGG PROCESSING SAFETY, QUALITY AND SECURITY Title: Microbiological Survey of Seven Types Retail Shell Eggs

Authors
item Musgrove, Michael
item Jones, Deana

Submitted to: Poultry Science
Publication Type: Abstract Only
Publication Acceptance Date: March 21, 2006
Publication Date: July 17, 2006
Citation: Musgrove, M.T., Jones, D.R. 2006. Microbiological survey of seven types retail shell eggs. Poultry Science Association Annual Meeting. p.135

Technical Abstract: A variety of shell eggs are available at retail, marketed to accommodate consumer preferences for esthetic, nutritional, or microbiological/safety perceptions and needs. In light of imminent changes to egg washing and packing regulations, any microbiological information on retail eggs processed under current guidelines will be useful for future comparison. A microbiological survey was conducted of eggs purchased in Athens, GA grocery and health food stores. Seven types of grade A large eggs were included in the study: (1) traditionally processed; (2) nutritionally enhanced; (3) in-shell pasteurized; (4) vegetarian fed; (5) free-range/fertile; (6) cage free; and (7) kosher. Eggs were transported back to the laboratory and ten were aseptically sampled by a shell/membrane crush method. Egg contents were also collected. Aerobic plate, Yeast/mold, and Enterobacteriaceae counts were determined for individual egg shells/membranes and content samples by plating on plate count, dichloran rose bengal chloramphenicol, and violet red bile glucose agar, respectively, using appropriate incubation times and temperatures. For each egg type, three 3-egg pools of shell/membrane homogenates and three 3-egg content pools were enriched for the detection of Salmonella, Campylobacter, and Listeria. Accepted methods of pre-enrichment, enrichment, selective plating, and confirmation were employed for each pathogen population. All microbial counts are reported as log cfu/mL for egg types 1-7. Aerobic egg shell/membrane counts by egg type were 1.2, 2.6, 1.5, 0.6, 1.4, 1.4, and 2.2, respectively. Yeast/mold counts were 0.1, 0.1, 0.3, 0.1, 0.2, 0.0, and 0.0, respectively, while Enterobacteriaceae counts were determined to be 0.3, 0.1, 0.3, 0.0, 0.2, 0.1, and 0.0, respectively. None of these populations was detected in any of the egg content samples. Salmonella, Campylobacter, and Listeria were absent from shell/membrane homogenate and content pools for all egg types sampled. These results indicate that shell eggs available in the retail market have acceptable microbiological quality and safety characteristics.

Last Modified: 12/20/2014
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