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

end of the storage time. These results depict that from the begining of storage after
processing; the spoilage micro flora counts were generally high compared to the counts of
laboratory chilled fillets. The interesting observation is that SSO and TVC were almost
parallel implying that the SSOs were already in big numbers following the 17 days storage
of whole Nile perch in ice. Figure 19 shows chemical (TVB-N) changes during storage of
the chilled Nile perch fillets. The trend shows constant lag phase compared to the
exponential changes of spoilage micro flora during the first 12 days of storage. The changes
were very narrow between 5-7mgN/100g up to 12 days of storage, but increased to
10mgN/100g during 12-15 days of storage. The general trends shows rapid increase of SSO
and TVC during the storage period, but moderate increase in TVB-N for the first 12 days
and then exponentially increase from 12-15 days of storage The changes in pH shifted from
6.62-6.82 units during the 15 days of storage.
Figure 18: Changes of specific spoilage
organism (SSO), total viable counts
(TVC) and Enterobacteriaceae (Ent.) on
chilled fillets.
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Figure 19: Changes of TVB-N on chilled
fillets
Figure 20: Changes of specific spoilage
organism (SSO), total viable counts
(TVC) and Enterobacteriaceae (Ent.)
and TVB-N on chilled fillets.