Microbiology and Spoilage Trail in Nile Perch (Lates niloticus), Lake ...

4.3.2.4 Establishment E4 – chilled fillets (5 days iced whole Nile perch)
Chilled Nile perch fillets were processed from a lot of whole Nile perch stored in ice for 5
days. Changes for spoilage bacteria on chilled fillets were constant up to 13 storage days
(figure 24 and 25). The trend was characterised by an increase for both SSO and TVC in
parralel and reached a stationary phase after 13-15 storage days. The changes in TVB-N
showed moderate increase from the beginning up to 13 days and then very rapid increase
between days 13-15. The SSO and TVC increased from 3-7log10cfu/g in the first 10 days of
storage and to 9 log10 cfu/g after 15 days while the Enterobacteriaceae counts gave only a
slight increase from 2.5-3.7 log10 cfu/g. Again these results indicate that the SSO counts are
closely equals to TVC counts between 13-15 storage days. The chemical (TVB-N) changes
during 15 days storage of chilled Nile perch fillets show an increase from about 5-
13mgN/100g up to 15 storage days (figure 25 and 26). The changes in pH shifted from 6.5-
6.9 units during 15 storage days.
Figure 24: Changes of specific spoilage
organism (SSO), total viable counts
(TVC) and Enterobacteriaceae (Ent.) on
chilled fillets.
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Figure 25: Changes of TVB-N on chilled
fillets.
Figure 26: Changes of specific spoilage
organism (SSO), total viable counts
(TVC), Enterobacteriaceae (Ent.) and
TVB-N on chilled fillets.