Organoleptic and microbial analysis of chrysichthys nigrodigitatus from Imo River, Nigeria smoked using different sources of heat
Date
2024-09
Authors
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Publisher
Federal University of Technology, Owerri
Abstract
This study is aimed to assess the microbiological and sensory quality of smoke–dried fish processed, using four different sources of heat (Charcoal, Firewood, Sawdust and Oven). A total of 300 fresh fish samples were randomly collected from Imo River for the study. The fish were divided into four batches of 75 fish per batch and processed using four different methods: Smokedried with charcoal (T1), Smoke-dried with firewood (T2), Smoke-dried with sawdust (T3) and Smoke-dried with oven (T4). Organoleptic assessment using a 5-point hedonic scale was also employed using a sensory evaluation while Microbial quality was determined from total coliform count and types of bacterial isolates. Data from Organoleptic assessment were analyzed using simple descriptive statistics such as percentages, pie charts and bar charts while microbiological data were statistically evaluated using the one-way analysis of variance (ANOVA). Results of organoleptic studies which evaluated the perception of four sensory criteria showed that for appearance/colour quality score was 9.0 (Charcoal), 7.2 (Firewood), 7.8 (Sawdust) and 9.5 (Oven). For Aroma, score was 7.8 (Charcoal), 7.6 (Firewood), 7.8 (Sawdust) and 9.4 (Oven). For Texture as sensory quality, score was 7.8 (Charcoal), 7.6 (Firewood), 7.8 (Sawdust) and 9.3 (Oven). Similarly, for Taste, the score was 9.0 (Charcoal), 7.4 (Firewood), 9.0 (Sawdust) and 9.7 (Oven). The result revealed that the organoleptic quality of fish dried using the oven as heat source gave the best sensory quality of excellence in terms of appearance/colour (9.5), aroma (9.4), texture (9.3) and taste (9.7). Results of Microbial analysis based on plate count method (cfu/g) and total viable bacterial count (TVBC) of pathogen food bacteria isolates, Escherichia coli and Klebsiella spp were as follows: For total coliform (cfu/g), Charcoal was (2.6×102), Firewood (2.9×102), Sawdust (2.6×102), Oven (2.2×102). E. coli was 1.5×102 (Charcoal), 1.8×102 (Firewood), 1.6×102 (Sawdust) and 1.2×102 (Oven). For Klebsiella spp, total viable bacterial count (cfu/g) was 1.1×102 (Charcoal), 1.1×102 (Firewood), 1.0×102 (Sawdust) and 1.0×102 (Oven). The results of microbial analysis showed that fish processed using the oven gave the lowest microbial load 1.0×102. It is thus recommended that where available and economical, oven processing/drying method should be adopted by fish producers. The use of oven in fish processing/drying will also mitigate the effect of deforestation which is the common source of charcoal, firewood and sawdust.
Description
This thesis is for the award of Master of Science (MSc.) in Fisheries and Aquaculture Technology
Keywords
Chrysichthys nigrodigitatus, organoleptic and microbial composition, different sources of heat, deforestation, Department of Fisheries and Acquaculture Technology
Citation
Jude, C. J. (2024). Organoleptic and microbial analysis of chrysichthys nigrodigitatus from Imo River, Nigeria smoked using different sources of heat (Unpublished Master Thesis). Federal University of Technology, Owerri, Nigeria