Preservation Of Eggs
Egg is a perishable product having short shelf life. The table eggs are of highest quality when they are laid. Preservation of eggs should start from the point of production itself. The following practices are recommended as routine for the production of quality eggs on the farm.
Collection of eggs at least 3 times daily.
Using a clean receptacle with ventilated sides and bottom, preferably filler flats.
Careful handling of eggs during collection and while storing in filler flats etc.,
Cooling the eggs quickly to 50oF or less at 75-85% relative humidity.
Marketing the eggs at least twice weekly.
However, the following changes on storage bring about spoilage.
Moisture loss through the pores
Gaseous (CO2) loss
Change of PH
Movement of water from thick albumen to other albumen layers and to yolk
Entry of microbes through the pores
Absorption of foreign odours
Egg preservation is therefore aimed at minimizing these changes in eggs under storage by employing various methods. Eggs can be preserved to improve the keeping quality either as shell eggs or as egg liquid (whole egg or yolk or albumen).
The methods for preservation of egg shell are based on simple principle of retarding the microbial growth and sealing the pores of the shell to minimize the evaporation of moisture and escape of gases, thus reducing the physico-chemical changes in the egg. Sometimes, a combination of methods is employed for effective preservation.
Egg is a perishable product having short shelf life.
The table eggs are of highest quality when they are laid.
Preservation of eggs should start from the point of production itself.
Immersion in liquids
This method is good for fertile eggs, since it kills embryos and therefore is also known as ‘defertilization’ method.
This includes flash heat treatment, thermostabilization and simultaneous coating.
In case of flashheat treatment, the eggs are immersed for 2 to 3 seconds in water at 71°C. Its advantage is that it destroys bacteria present on the surface of shell besides coagulating a thin film of albumen immediately beneath the shell membrane and thus seal the shell internally.
In thermostabilization, the eggs are immersed in water at 49°C for 35 minutes or 54°C for 15 minutes or 56°C for 10 minutes or 60°C for 5 minutes in order to stabilize the thick albumen so that such eggs retain fresh appearance much longer than unheated eggs
Simultaneous oil coating and thermo stabilization complement each other in maintaining the internal quality of egg.
Immersion in liquids:
Under village conditions liquids like lime water and water-glass are very useful for egg preservation.