P2-122 Impact of Alternative Antimicrobial Commercial Egg Washes on Reducing Salmonella Contamination

Monday, July 27, 2015
Exhibit Hall (Oregon Convention Center)
Lauren Hudson , Department of Food Science and Technology , Athens , GA
Mark Harrison , University of Georgia, Department of Food Science and Technology , Athens , GA
Mark Berrang , USDA, ARS,RRC , Athens , GA
Deana Jones , U.S. Department of Agriculture-ARS , Athens , GA
Introduction: Table eggs are washed with an alkaline detergent (approx. pH 11) followed by a chlorine rinse. Minimum wash water temperature is 32°C, but frequently as high as 49°C. Wash temperature and an antimicrobial rinse are required by regulation, but wash pH is not specified. At pH 11, little, if any, free chlorine is available in the final rinse. Using a chlorine stabilizer (e.g., T-128) in the wash may help maintain chlorine effectiveness. The heated wash warms eggs and slows cooling, which can encourage microbial growth. 

Purpose: The objective was to determine the effectiveness of four egg wash treatments to decrease Salmonella contamination: chlorine+T-128 at pH 6.0 at both ambient temperature (approx. 20°C) or 49°C and alkaline wash at pH 11 at both ambient temperature or 49°C. 

Methods: Eggs were drop inoculated with Salmonella Typhimurium and Salmonella Enteritidis and were washed with each of the treatments. All wash treatments were followed by a chlorine rinse. Two control treatments were also evaluated: inoculated, not washed and inoculated, washed with 20°C water. Post-wash Salmonella counts were compared to determine intervention effectiveness. 

Results: Salmonella counts were reduced by similar levels when washed with chlorine+T-128 at both temperatures and with the alkaline wash at the high temperature (~5 log CFU/ml egg shell emulsion reduction); these treatments were not significantly (P > 0.05) different from each other. The counts were significantly (P < 0.05) lower than the 20°C alkaline treatment and 20°C water treatment counts (~3.2-log CFU/ml reduction). 

Significance: Results show that acidic washes may provide the same results as the traditional egg wash and that, for the acidic washes, ambient temperatures were just as effective as heated washes. The traditional basic egg wash does not show the same antimicrobial effectiveness when applied at ambient temperatures.