Effect of
age on egg quality
The age of hen is another factor
influencing egg weight. (Peeble et al.,
2000), Silversides and Scott (2001), (Oloyo, 2003). (Van et al., 2004), Rizzi and Chiericato (2005), Johnston and Gous
(2007) shows that egg weight increased with the hen’s age. On the other hand,
Zemkova et al., (2007) demonstrated
that the egg weight was not influenced significantly by age. The age of hen
also increased yolk weight Rossi and Pompei, (1995); Rizzi and Chiericato
(2005); but decreased albumen percentage van et al., (2004), Rizzi and Pompei,
(1995).
The age of hen influenced egg shell quality, silversides and Scott
(2001); campo et al., (2007 which deteriorate with advancing age of hens. On
the other hand, Yannakopoulos et al.,
(1994) observed that there is no significant effect of age on egg shell
thickness.
Effect of Egg Handling On Egg Quality
Egg handling is the total treatment
egg must endure on the way from laying unit to the consumers. Without giving a
definition of quality, eggs have to meet certain quality standards. It is
generally accepted in the egg business that the shell should be intact and clean.
Consumers will generally ask for fresh eggs in terms of quality, this means
that egg content must be very much like those of a newly laid egg. It would be
a mistake however to suppose that newly laid egg necessarily have the best
interior quality. Peelability for instance is a problem with newly laid eggs
and consumers who have never eaten a real fresh egg will complain about the structure
of the white, when it has been boiled. Nevertheless, the egg content have to
meet certain quality standards.
When an egg is being laid, it is
intact and clean. Only environmental conditions can cause damage to the shell.
It is only after oviposition that the
shell can get soild.
Once eggs enters atmospheric conditions,
changes occurs to the shell contents. The air cell forms due to decrease in temperature and it encourages
evaporation of water through the pore in the shell. Carbon dioxide escape from
the albumen causing an increase in pH. At the same time, the quality of firm
albumen decreases and there is an increase in thin Albumben. Leandro et al., (2005) and Menezes et al., (2009) reported that the
temperature and relative humidity are the most important factors affecting egg
quality during storage. Long term storage may cause special problems, like
mould growth and change in flavour.
Though oiling eggs is not forbidden in
Nigeria,
it is not useful since washing is not allowed. Egg washing is concerned with
the maintenance of certain characteristics of egg content. According to
Kurtweit, (1996) rough handling of eggs increase the risk of breaking and
causing internal egg quality problem.