COMPARATIVE STUDY OF MICROBIAL QUALITY AND HEAVY METALS CONTENT OF FRESH AND SMOKED DRY MULLET(Mugil cephalus) AND SILVER CATFISH (Chrysichthys nigrodigitatus)
Published 2023-10-19
Keywords
- Bacterial, Fungal isolate, Heavy metals, Microbial quality, Silver Catfish.
How to Cite
Abstract
Seafood has continued to serve as a major source of protein and other useful nutrients, making
it an important component of a healthy diet. The microbial and heavy metals content of fresh
and smoked Mullet and Silver catfish (MSc) were evaluated. The skin, gills and liver were
aseptically removed. Ten folds serial dilution was carried out on each sample, while bacterial
and fungi were isolated and identified. Mineral analysis was carried out using standard method
and data obtained were analysed using ANOVA while means were compared using Duncan
Multiple Range Test. Total viable bacteria count for fresh MSc (CFU/ml); Skin(0.8 x 106
– 9.7
x 106; 0.7 x 106
– 7.6 x 106), Gills(0.3x106
–5.0x106; 0.1x106
– 8.9x106), Liver(0.2x106
–4.5x106;
0.1x106
–5.3x106), while smoked MSc; Skin(1.0x106
– 6.0x106; 1.8x106
– 7.8x106),
Gills(1.13x106
– 8.0x106; 0.6x106
–3.2x106), Liver(1.2x106
–6.2x106; 3.9x105
-1.4x106).
Probable organisms isolated include; Enterobacter aerogenes, Escherichia coli, Pseudomonas
aeruginosa, Staphylococcus spp, Klebsiella pneumonia, Aspergillus spp, Rhizopus sp, Fusarium
sp and Penicillium spp. Metal concentrations (mg/kg) varied significantly (p < 0.05) within
locations and in skin, gills and liver with ranged; Fe(297.00±1.41-32.50 ± 0.71) > Zn(3.65±0.07-
112.80±3.11) > Mn(0.08±0.01-2.2±0.35) > Pb(0.00 ± 0.00-0.85 ± 0.01) > Cr(0.95 ± 0.01-0.20
± 0.01) > Cd(0.00±0.00-0.40±0.00) > Cu(0.01±0.04-1.50±0.01) while Fe(59.95±0.21-
222.0±2.82) > Zn(41.60±0.14-19.60±1.40) > Cu (7.01±0.01-2.40±0.01) > Mn(0.00±0.00-
0.16±0.01) > Cr(0.34± 0.01-0.09±0.01) > Pb(0.67±0.01-0.02±0.00) > Cd(0.00±0.00-0.03±0.00)
in Makoko and Epe samples respectively. In this study Zn, Mn and Fe concentrations in Skin,
Gills of Mullet were higher than WHO/FAO permissible limits, while Cd was recorded below
detection limits. The presence of pathogenic microorganisms in these fish samples calls for
serious public concern. To ensure food safety, adequate processing is required before
consumption.