Submitted to: Foodborne Pathogens and Disease
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 2/6/2009
Publication Date: 5/1/2009
Citation: Gurtler, J., Conner, D.E. 2009. Survival and Growth of Salmonella Enteritidis in Liquid Egg Products Varying by Temperature, Product Composition, and Carbon Dioxide Concentration. Foodborne Pathogens and Disease. 6(5):1-7.
Interpretive Summary: Rapid cooling of eggs in the presence of carbon dioxide (CO2) is known to improve the quality of eggs. However, research is needed to determine the effects of varying CO2 levels on Salmonella, which is sometimes present in eggs. In this study egg products were inoculated with Salmonella, exposed to three at different CO2 concentrations, and stored at temperatures from 45F to 99F. Our results suggest that increasing atmospheric CO2 to enhance egg quality should not promote the growth of Salmonella in eggs. These finding will be useful to the egg industry in developing ways of promoting egg quality without compromising food safety.
Technical Abstract: Cryogenic cooling of shell eggs with carbon dioxide (CO2) is known to improve egg content quality through rapid cooling as well as by increasing internal CO2 levels. A preliminary study was undertaken to determine the effects of variations in atmospheric CO2 concentrations (aerobically stored, flushed with CO2 and sealed, or bubbled with CO2) on the survival and growth of Salmonella Enteritidis in liquid egg products including whole egg (WE), albumen (A), yolk (Y), and albumen + 1 percent yolk (AY). Egg products were inoculated with a three-strain composite of S. Enteritidis at a population of ca. 4 log CFU/ml and stored at 7, 10, or 23C for 8, 4 or 2 days, respectively, or at ca. 2 log CFU/ml and stored at 23C and 37C for 48 or 24 hours, respectively. Salmonella populations differed based on variations in liquid egg composition (P < 0.001), although manipulating the atmospheric concentrations of CO2 in which liquid egg products were stored did not significantly inhibit the growth of S. Enteritidis (P > 0.05) in yolk-containing egg products or affect the inhibitory activity of albumen-containing products. Populations of Salmonella were static at 7C over the entire storage period and significant growth occurred in WE and Y stored at 10C, while populations in egg stored at 23 and 37C were greater in Y than in WE, which had populations greater than in A or AY (P < 0.05). Results of this investigation suggest that increasing atmospheric CO2 to enhance egg quality should not promote the growth of S. Enteritidis in eggs.