Eggs slowly deteriorate through storage hence the statutory E.U. limit of Best Before 28 days from date of lay.
“Lion” code eggs have a lower limit of 21 days from date of pack and no more than 4 days from pack to lay giving a maximum life of 24 – 25 days.
Usually eggs reach retail stores within 2 – 3 days of being laid.
As an egg ages it loses moisture through the shell by evaporation and the white becomes slightly runnier due to proteins denaturing within the egg. This aging can be slowed keeping egg quality better and safer, by storage in fridges or cool larders, it is not recommended to keep eggs in the kitchen, in direct sunlight in egg baskets etc.
Eggs should preferably be stored in their pack in the fridge but regardless of this should be placed vertically point end down (with the air cell to the top) and kept away from strong smells such as fish, onion, garlic etc as the shell is porous and can absorb such strong smells which can cause taints.