Spice Combination and Its Comparative Effect on Proximate Composition and Microbial Load of Smoked Clarias gariepinus

Abstract

Fish, a major source of animal protein in Nigeria, is lost annually to spoilage because of improper storage and inadequate preservation techniques. Synthetic antioxidants have gradually lost their use and value in the industry because of their reported undesirable effects. Furthermore, synthetic preservatives are not readily available and are expensive for local fish processors. Hence, there is a need for natural and locally sourced preservatives. This study investigated the effects of spice combinations on the microbial load and proximate composition of smoked Clarias gariepinus. Four treatments were used, each with three replicates. Treatment 1 comprised Monodora myristica, Zingiber officinale and Piper guineusis. Treatment 2 comprised Monodora myristica, Zingiber officinale and Xylopia aethipica. Treatment 3 comprised Monodora myristica, Zingiber officinale and Allium sativum, whereas treatment 4 comprised a brine solution and served as the control. The smoked fish was stored for 21 days and sampled every 7 days. The total coliform count (TCC) results showed higher initial values for all treatments, with no significant differences (p > 0.05) among them. After smoking, the TCC values decreased in all treatments, with treatment 4 recording the highest value (1740), which differed significantly (p < 0.05) from those of the other treatments, followed by treatment 1 (1300). The total viable count (TVC) results showed that the initial values were higher than those obtained after treatment and during storage. After smoking and after 1 week of storage, treatment 4 recorded the highest TVC values of 2640 and 2240, respectively, which differed significantly (p < 0.05) from those of the other treatments. Treatment 2 recorded the lowest TVC values of 940 and 1120, respectively, which were also reported as significantly different (p > 0.05) from those of the other treatments. The proximate composition results showed that the moisture content of treatment 2 after smoking differed significantly (p < 0.05) from those of the other treatments, whereas treatments 1, 3 and 4 did not differ significantly (p > 0.05). Crude protein content generally did not differ significantly (p > 0.05) among treatments at the initial assessment, after smoking or at the end of storage. The findings indicated that smoked fish treated with M. myristica, Z. officinale and X. aethipica (treatment 2) had the best performance.