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.


  1. 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.

  2. 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.

  3. 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.