Aim-Preservation of whole egg

            The spoiling of eggs is due to the entrance of air carrying germs through the shells. Normally the shell has a surface coating of mucilaginous matter, which prevents for a time the entrance of these harmful organisms into the egg. But if this coating is removed or softened by washing or otherwise the keeping quality of the egg is much reduced. Some bacteria, however, are just as happy feasting on eggs as we are, however, and they do three things:
-- they use available gases in the egg to power their metabolisms
-- they degrade the proteins which compose the egg
-- they produce nitrogenous and sulfurous waste products
            As an egg ages, water and CO₂ diffuse out through pores in the shell, which raises the pH (it becomes more alkaline). The pH of the white of a freshly-laid egg is between 7.6 and 7.9, but that is largely due to the presence of CO2, which is slightly acidic. As the CO2 is lost, the more alkaline compounds predominate and pH rises.
            The yolk is different, though -- it's more acidic to begin with because of its composition, around 6.2, and age alone does not affect that pH much.
Other methods follow:

1.      Egg Cleaning-A temperature difference of 10-15⁰C between eggs and wash water is ideal; otherwise there may be problem of crack shells. After washing, the eggs should be dried promptly. Wash water should be changed after washing every five to six baskets of eggs.

2.      Oil Treatment- Oil coating spay of eggs has become very popular for short term storage of this commodity. Coating oil forms a thin film on the surface of the shell sealing the pores. It should be done as early as possible, preferably within first few hours after laying of eggs because loss of CO₂ is more during this period and evaporation of moisture is also more during the first few days. Egg coating is done by dipping the eggs in the groundnut oil whereas for oil spray, the eggs are arranged in the filler flats with their broad end up. The temperature of oil should be in range of 15 to 30⁰C for ideal results.

3. Cold Storage- This method of preservation is suitable for long tern storage of clean eggs in the main laying season and abundant availability. The temperature of cold store is maintained at 0⁰C (32⁰F) and relative humidity between 80 to 85 per cent. The quality of shell eggs can be maintained for about 6 months in a cold storage. Oil coating of eggs prior to cold storage can further enhance their keeping quality. Such eggs could keep well at 14⁰C and 90% RH for a period of 8 months.
4. Thermostabilization- This preservation method involves stabilization of albumen quality by holding the eggs in an oil bath maintained at 55⁰C for 15 minutes or 58⁰C for 10 minutes. This process brings about coagulation of thin albumen just below the shell membranes, thereby blocking the passage of air and moisture.
5. Immersion in Liquids- Under rural conditions, lime-water or water –glass immersion are most useful. In lime-water treatment, a litre of boiling water is added to 1 kg of quick lime and allowed to cool. Eggs are dipped in the clear fluid overnight and then dried at room temperature. In this process, an additional thin film of calcium carbonate is deposited on the egg shell and seals the pores. Such eggs can be stored for a month at ambient temperature. In water-glass treatment, one part of sodium silicate is mixed in 10 parts of water and eggs are dipped overnight.