EFFECT OF SELECTED OIL TREATMENT ON MICROBIAL LOADS OF SOME SMOKED FRESHWATER FISH SPECIES

Abstract

The study investigated the effect of selected oil treatment on microbial load of some smoked freshwater fish species.
Forty-two (42) fish samples comprising Clarias gariepinus, Heterotis niloticus and Proptopterus annectens with mean
weight of 650g was procured from Wadata fish landing site, Makurdi, Benue State, Nigeria. The fish samples were
washed and grouped into batches, immersed in 5 % brine solution for 30 minutes within ambient temperature of 30±2
0C. They were smoked using smoking kiln. Batch A, (Control) was not treated while the other three batches- B, C and
D were immersed in 30 ml of soybean, groundnut and castor oil respectively and dried on laboratory table. Subscripts
1, 2 and 3 indicate species from C. gariepinus, H. niloticus and P. annectens respectively. Smoked fish samples were
subjected to microbial analysis. The results indicated that oil application, fish species and storage duration are
significant (p<0.05) effect on microbial load. The total viable count (TVC) ranged from 4.01 to 5.17 LogCFU/g as
storage duration increases. Total coliform count (TCC) was least (3.95±0.11 LogCFU/g) in C. gariepinus and greatest
in P. annectens. Mean values of TCC increased with storage time from 3.38± 0.07 LogCFU/g at week 0 to 4.50±0.05
LogCFU/g. Total fungal count (TFC) increased from 3.44 ± 0.03 to 4.12±0.03 LogCFU/g as storage time increased
from 0 to 8 weeks. Groundnut, soybean and castor oil have demonstrated effect in controlling microbial count below
control level. Castor oil showed the least potential of keeping lowest microbial counts after the duration of 8 weeks.