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International Journal of Aquaculture, 2014, Vol.4, No.21 123
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130
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125
Table 3 Overall acceptability of smoked
C. gariepinus
with different concentration of salt and pepper spice mixture
Treatment
AFTER 24 HOURS
6 WEEKS
12 WEEKS
18 WEEKS
Overall acceptability
Overall acceptability
Overall acceptability
Overall acceptability
Control
6.49±0.02a
4.91±0.04a
4.07±0.01a
3.03±0.01a
E2
6.55±0.01a
5.18±0.02ab
4.23±0.00ab
3.30±0.02ab
E3
6.57±0.03a
5.41±0.03bc
4.49±0.00abc
3.46±0.01b
E4
6.68±0.02a
5.72±0.01c
4.72±0.01bc
3.88±0.01c
E5
6.72±0.01a
5.80±0.05c
4.91±0.01c
4.15±0.00c
Note: Keys: E
1
= smoked fish without spice (control) E
2
=smoked fish with 5% spice; E
3
= smoked fish with 10% spice; E
4
=smoked
fish with 15% spice and E
5
=smoked fish with 20% spice
(2.91 log
10
cfu/g; 53.31 log
10
cfu/g) at 24 h after
smoking and 18 weeks respectively and the least in
20% spice mixture of salt and pepper (2.26 log
10
cfu/g;
8.13 log
10
cfu/g) at 24 h after smoking and 18 weeks
respectively (Table 4).
1.5 Probable bacteria in smoked C. gariepinus
The bacterial isolates obtained at 18 weeks were
identified as
Staphylococcus aureus
,
Clostridium
welchii
,
Proteus morganii
,
Escherichia coli
and
Bacillus subtilis
. The characterization of the isolates is
as shown in Table 5.
2 Discussion
In assessing the quality of a fish the consumer may
consider its freshness, the safety of the fish in terms of
the microbial load and the presence or absence of
pathogenic organisms as well as the palatability of the
fish. The moisture content of the fish subjected to
different treatments decreased after smoking. This
decrease was due to loss of water during smoking but,
the values increase in all treatments after 18 weeks.
This may be due to environmental factors that brought
increases in moisture content of fish. This is similar to
Fakunle
et al.
(2009). The moisture content of the
dried catfish is of a great importance during storage,
the result of this study showed that the moisture
content was still at a safe level (9.59 -12.82%) which
is within the recommended safe moisture content of
dried fish (8 to 13%) as reported by World Health
Organization.
Table 4 Total viable count of smoked
C. gariepinus
with different concentration of salt and pepper spice mixture
Treatment
AFTER 24 HOURS
18 WEEKS
Total Viable Count (log
10
cfu/g)
Total Viable Count (log
10
cfu/g)
Control
2.91±0.01e
53.31±0.02e
E2
2.84±0.01d
42.79±0.03d
E3
2.77±0.02c
28.78±0.03c
E4
2.34±0.01b
15.31±0.00b
E5
2.26±0.00a
8.13±0.00a
Note: Keys: E
1
= smoked fish without spice (control) E
2
=smoked fish with 5% spice; E
3
= smoked fish with 10% spice; E
4
=smoked
fish with 15% spice and E
5
=smoked fish with 20% spice
There was a general increase in the crude protein
content of the fish after smoking (24 hours), this
might be due an increase in the dry matter content per
unit of weight following sample dehydration during
smoking and reduction in the moisture contents after
the smoking before autolysis becomes pronounced.
Decreases in values of crude protein were observed in
all the treatment at 18 weeks. This might be as a result
of long period of storage. Although higher crude
protein was observed in treated group (58.39 – 63.24)
compared to the control (55.79) and these values
differs significantly (p< 0.05) among the treatments.
This agrees with the findings of Puwastien
et al
.
(1999), and Tao and Linchun (2008) who recorded
increased in crude protein in treated groups compared
to the control. This increase may be due to the
preservatives effects which slow down autolysis in the
fish muscles and consequently slow down the protein
break down. However, this result shows that storage
time may cause a decrease in the protein content of
smoked catfish which is similar with the report of
Ufodike and Obureke (1989) where there was