Using cool water helps the eggs to cool down more quickly, which reduces the risk of pathogen growth both inside and outside the shell, according to research published in the Journal of Food Safety in December.
The research findings may provide a simple method for reducing egg contamination.
The researchers from the US Department of Agriculture
and the Auburn University
tested three water temperature schemes in dual washing commercial systems. The first test used water at 49 degrees Celsius for both washes of the eggs.
The second used water at 49 degrees Celsius for the first wash and 24 degrees Celsius for the second. The third used water at 24 degrees Celsius for both washes.
They found that using warm temperature water in a first wash and cooler water in a second wash could provide the greatest benefit by both reducing egg temperature and microbial levels.
While Salmonella, Campylobacter and Listeria were all detected in shell emulsion and wash-water samples from cool-water washing treatments, none were detected in the eggs contents throughout the storage period of eight weeks.