Skip to main content
ARS Home » Research » Publications at this Location » Publication #182672


item Jones, Deana
item Musgrove, Michael
item Northcutt, Julie

Submitted to: Feedinfo News
Publication Type: Trade Journal
Publication Acceptance Date: 7/1/2005
Publication Date: 7/5/2005
Citation: Jones, D.R., Musgrove, M.T., Northcutt, J.K. 2005. Changes in the microbial populations of shell eggs during extended storage. Feedinfo News Service Scientific Reviews. July 2005. Available from URL:

Interpretive Summary:

Technical Abstract: A research project was conducted to determine the microbial quality of commercially processed shell eggs during extended storage. Unwashed eggs were collected at the accumulator before entering the processing line. Washed eggs were retrieved after placement in flats. All eggs were stored on pulp flats at 4ºC for 10 weeks. Twelve eggs from each treatment were rinsed on the day of collection and each week of storage. After rinsing, eggs were sanitized in ethanol and contents aseptically collected. Total aerobes, yeasts and molds, Enterobacteriaceae and pseudomonads were enumerated from shell rinses and pooled egg contents. During storage, no differences were found between unwashed and washed eggs for Enterobacteriaceae and pseudomonads in either shell rinses or contents. No differences were found between treatments for population levels of total aerobes or yeasts and molds in the egg contents throughout the storage period. Significant differences occurred at each week of storage for external shell contamination by total aerobes between treatments. The greatest of contamination on unwashed eggs occurred at 8 weeks of storage and lowest at 0 and 1 week of storage. The highest level of shell contamination with aerobic bacteria on the washed eggs was found at 0 week of storage and the lowest level at 7 weeks. Yeast and mold contamination levels were also significantly different during each week of storage between treatments for shell rinses. Eggs washed under recommended U.S. guidelines were significantly less contaminated than unwashed eggs for the populations monitored.