Board and Tranter (1995) reported that the extent of contamination
of hatching eggs was in the range from 2 to 7 log (102 up to 107
)
cfu per egg shell. In egg washing experiments, Knape et al. (2002) and
Favier et al. (2000), reported an average initial egg shell contamination
of 6.33 and 4.55 log cfu/egg shell respectively.
In the current experiment, although the dose of bacterial
inoculation was very high, it was within the normal contamination
range described in earlier studies by Board and Tranter (1995) and
Knape et al. (2002). However during the present study, eggs were
washed in 70% ethanol prior to external inoculation which may have
damaged the cuticle, reducing its protective properties. There is stillthe possibility that pathological lesions in egg shells like cuffing, type
B bodies and depressions, seen in the translucent egg shells, could
have potentiated the entry of bacteria across the egg shell. The
translucent egg shell surface can increase the likelihood of internal
contamination of eggs. In the present study, however, the bacterial
contamination of the egg shell was not quantified and further
research is needed in this area.