Even with good farm-management practices and careful handling, a small percentage of dirty eggs will be produced. Producers must bear in mind that dirty eggs are covered with bacteria that will cause spoilage if they enter the egg. Whether conducted at the production or processing site, washing must be performed in a manner that will minimize the chances of bacterial penetration of the shell.
If these important facts are forgotten, and eggs are washed carelessly, more damage can be done than by leaving the dirt on the shell. Wetting a dirty shell provides moisture in which bacteria may breed and assists their growth and penetration through the shell. A washing solution colder than the egg causes the egg content to contract and thus allows polluted water to be drawn through the shell.
So when washing eggs the following precautions should be followed:
1. Wash Eggs with water at least 20 °F (11.1 °C) warmer than the internal temperature of the eggs and at a minimum of 90 °F (32.2 °C).
2. Select a detergent or detergent sanitizer that is compatible with the wash water and one that will not give off foreign odors that may be imparted to the egg.
3. Use only potable water with an iron content of less than 2 parts per million (p/m) for washing and keep wash water as clean as possible.
4. Rinse by spraying with water slightly warmer than the wash water.
5. Use an approved sanitizer in the spray rinse.
6. Dry the eggs to remove any excess moisture prior to packaging.
“Whether conducted at the production or processing site, washing must be performed in a manner that will minimize the chances of bacterial penetration of the shell”
After washing, eggs should be rinsed with a warm water spray containing an approved chemical sanitizer to remove any remaining bacteria. The strength of the sanitizing spray should be no less than 50 p/m nor more than 200 p/m of available chlorine or its equivalent.
Research has shown that during the washing process, most of the outer cuticle on the egg shell is removed. Removal of this cuticle increases the rate of carbon dioxide and moisture loss of the internal egg contents.
To reduce the rate of loss, spraying the eggs with a light coating of food grade mineral oil is a common practice. For best results, the entire oiling system, including spray nozzles, filters, and oil storage reservoir, should be checked frequently to assure that the equipment is functioning adequately and that the oil is free from contamination.