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International Journal of Aquaculture, 2014, Vol.4, No.21, 123
-
130
http://ija.biopublisher.ca
123
Research Article Open Access
Microbial Safety and Quality of Smoked
Clarias gariepinus
Burchell, 1822 on
Different Concentration of Preservatives during Ambient Storage
A. O. Isaac, S. E. Olusola , O. A. Oyelese
Department of Wildlife and Fisheries Management, University of Ibadan, Nigeria
Corresponding author Email
International Journal of Aquaculture, 2014, Vol.4, No.21 doi: 10.5376/ija.2014.04.0021
Received: 28 Mar., 2014
Accepted: 21 May, 2014
Published: 24 Jun., 2014
Copyright © 2014
Isaac et al., This is an open access article published under the terms of the Creative Commons Attribution License, which permits unrestricted
use, distribution, and reproduction in any medium, provided the original work is properly cited.
Preferred citation for this article
:
Isaac et al., 2014, Microbial Safety and Quality of Smoked
Clarias gariepinus
Burchell, 1822 on Different Concentration of Preservatives during Ambient
Storage, International Journal of Aquaculture, Vol.4, No.21: 123-130 (doi: 10.5376/ija.2014.04.0021)
Abstract
This experiment was conducted to assess the microbial safety and quality of smoked
Clarias gariepinus
using different
concentrations of pepper and salt spice mixture as preservatives. Ninety catfish,
C.
gariepinus
(1,000 – 1,250g) were allocated to five
treatments and replicated twice. The prepared weight to weight spice mixture of pepper 50% and salt 50% was neatly rubbed on the
C.
gariepinus
using different concentrations after degutting: E
1
= 0%, E
2
= 5%, E
3
=10%, E
4
= 15%, E
5
= 20%. The
C.
gariepinus
were
cold smoked in an oven between 40
℃
to 65
℃
for 6 hours and hot smoked between 120-150
℃
for 18 hours. Storage studies were
carried out on the processed fish for 18 weeks (24 h after smoking, 6, 12 and 18). Proximate composition, organoleptic assessment,
Total Viable Count (TVC), biochemical parameters such as Peroxide Value (PV), Thiobarbituric Acid (TBA), Free Fatty Acid (FFA)
and Total Volatile Base (TVB) were assessed. Data were analyzed using descriptive statistics and ANOVA at p = 0.05. Results
obtained showed that crude protein of
C. gariepinus
were better in treated groups compared to the control and increased with
increasing level of pepper and salt spices at 18 weeks. Also, better organoleptic assessment was recorded in treated groups compared
to the control, best assessment was recorded in 20% spice mixture (6.72, 5.80, 4.91, 4.51) compared to the control (6.49, 4.91, 4.07,
3.03) after 24 hours, 6, 12 and 18 weeks respectively and were significantly different (p <0. 05) from the control. Total viable count
from the study revealed that bacteria loads in smoked
C. gariepinus
were decreased in pepper and salt spice mixture than the control
after 24 hours and 18 weeks and this were significantly different ( p <0. 05) than control. The PV, TBA, FFA and TVB were lower in
the treated groups compared to the control after 24 hours, 6, 12 and 18 weeks. These results indicated that using pepper and salt spice
mixture may be useful in improving the shelf life and consumer acceptability of smoked
C. gariepinus
and it was concluded that 20%
spice mixture would positively influence shelf life, reduce and prevent bacteria pathogens in smoked
C. gariepinus
.
Keywords
Clarias gariepinus
; Preservatives; Microbial safety; Organoleptic assessment; Proximate composition
Introduction
Fish is one of the most important animal foods
available in the tropics (Eyo, 2001). Catfish, (
C.
gariepinus
) accounts for about 80% of aquaculture
production in Nigeria (FDF, 2003). Catfish are a lean
and highly nutritious fish that contain high amounts of
vitamins, proteins, minerals, and little or no saturated
fat, and is low in carbohydrates. However, catfish like
any other fish species, could result in significant
economic loss due to its perishable nature, if adequate
preservation techniques are not adopted (Clucas and
Ward
,
1996). Fish and fisheries products are among
the most perishable commodities worldwide mainly
due to microbial spoilage. About one-third of the
world’s food production is lost annually as a result of
microbial spoilage (Omojowo et al., 2010).
Smoking is the process through which volatiles from
thermal combustion of wood penetrate meat or fish
flesh (Simko, 1991). Hard curing by salting and
smoking permits lengthy preservation by removing
moisture, which is essential for bacteriological and
enzymatic spoilage (Antonia da Silva, 2002). Various
food preservation techniques have been utilized to
improve the microbial safety and extend the shelf life
of fish in general including freezing, chemical
preservation, salting, and smoking (Nickelson
et al
.,
2001). The quality of smoked product is dependent on
several factors including the quality of the fish at the
time of smoking, and the nature of wood and type of
smoking procedure employed (Antonia da Silva,
2002). Consumers are rediscovering the good taste of
smoked seafood, including smoked catfish. To satisfy
the consumer demand, it is necessary to produce good
quality and safe smoked seafood products. The