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

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Figure 13: Changes of specific spoilage
organisms (SSO), total viable counts
(TVC), Enterobacteriaceae (Ent.) and
TVB-N in chilled fillets from newly
caught Nile perch.
4.3 PHASE III: MICROBIOLOGY OF WHOLE NILE PERCH SWABS, ON LINE
FILLETS AND SHELF LIFE OF ESTABLISHMENTS CHILLED FILLETS
4.3.1 Phase III - Trial 1: Microbiology of whole Nile perch swabs and online fillets
Whole Nile perch is normally collected from various landing sites on shore and islands of
Lake Victoria. Whole Nile perch is not washed nor guted at fishing grounds/upstream. It is
collected and iced in the transportation vessels, insulated boats and trucks at islands or
landing sites. Usually collection vessels collect fish at minimum of 3 days to maximum of 3
weeks (21days), during this period the fish is stored in ice until transported to the
establishments. The fish is off loaded and washed at the receiving section of the
establishments. There are at least two washing stages. At the first stage the fish is scrubbed
using brush (coloured) and washed with runnig/shower water. Then it is rinsed in next
(second) stage by another handler/person and finally size graded and placed in a container
(figure 14) with melting ice and stored chilled until they are subjected to alternative
processes. The tables 18 and 19 below show the microbiological results for TVC and
Enterobacteriaceae before (BW) and after washing (AW) of whole Nile perch and online
fillets prior to the super chilling stage at three fish processing establishments (E1, E2, &
E3).