ARS | Publication request: EFFECTS OF COOL WATER WASHING OF SHELL EGGS ON HAUGH UNIT, VITELLINE MEMBRANE STRENGTH, AEROBIC BACTERIA, YEAST, AND MOLD

Submitted to: Poultry Science
Publication Type: Abstract Only
Publication Acceptance Date: April 18, 2006
Publication Date: July 16, 2006
Citation: Caudill, A.B., Curtis, P.A., Jones, D.R., Musgrove, M.T., Anderson, K.E., Kerth, L.K. 2006. Effects of cool water washing of shell eggs on haugh unit, vitelline membrane strength, aerobic bacteria, yeast, and mold. Poultry Science.85(1):100

Technical Abstract: ABSTRACT Current egg washing practices utilize wash water temperatures averaging 49C, and have been found to increase internal egg temperature by 7-8C. These high temperatures create a more optimal environment for bacterial growth, including Salmonella Enteritidis (SE), if it is present. However, SE, the most common human pathogen associated with shell eggs and egg products, does not grow well at lower temperatures. This study’s objective was to determine if commercially washing eggs in cool water would aid in quickly reducing internal egg temperature, creating an environment less beneficial to bacteria and preserving egg quality. During three consecutive days eggs were washed at an off-line (Plant A) and an in-line (Plant B) commercial facility. Four dual tank wash water temperature schemes were used (WW = 49C, 49C; WC = 49C, 24C; CC = 24C, 24C; CW = 24C, 49C). Wash water pH ranged from 10.85 to 11.14 throughout the study. A 10 week storage study followed, in which vitelline membrane strength, Haugh unit, and presence of yeast, mold, and aerobic bacteria were monitored weekly. Haugh unit values and vitelline membrane strength declined over time; however, wash water temperature schemes did not significantly affect egg quality. There were no differences in yeast and mold found in the contents or on exterior shell surfaces of eggs from either plant. No significant differences in aerobic bacteria present in contents or on exterior shell surfaces of eggs for each temperature scheme from Plant A were found. The amount of aerobic bacteria found in contents and on exterior shell surfaces of eggs from Plant B was significantly lower for the WW temperature scheme; differences were within 1 log cfu/mL for contents (WW = 2.2; WC = 2.7; CC = 2.6; CW = 2.6) and slightly above 1 log cfu/mL for exterior shell surfaces (WW = 1.7; WC = 2.0; CC = 2.8; CW = 2.7). This study’s results indicate that commercial cool water washing did not affect interior egg quality or the microbial integrity of interior egg contents. (Key words: shell eggs, cool wash, egg quality)