Studies on the Fungal Infestation of three traditionally Smoke-dried freshwater fish species in Kainji Lake Area, Nigeria

Abdulrahman  Muhammad; Falmata Ali Mustapha; Yusuf Madaki Lekko; Adamu Saleh Saidu; Sani  Mohammed; Muhammad  Mustapha

doi:10.5455/JRVS.20250729110047

Abstract
Background and Aim: Fish is an important source of quality protein, but has been observed that smoked dried fish are mostly contaminated with microorganisms from processing to market.
Methods: Twenty (20) samples each of three species studied, were selected and subjected to sensory evaluation, the quality of the samples based on the organoleptic parameters of texture, odour, taste and appearance on a scale of 1 to 8. The samples were then incubated on Sabouraud Dextrose Agar (SDA) and examined for seven days for fungal infestation. Mean and standard deviation of mean were calculated for the scores of the sensory evaluation of the fish, and analysis of variance (ANOVA) using GraphPad Prism Version 8.0.2.
Results: The total percentage species of fungi isolated and identified from the three species of fish included Aspergillus flavus (28.3%), Aspergillus niger (48.3%), Penicillium riqueforti (26.7%), Cladosporium herbarum (13.3%), Cladosporium sphaerospermum (11.6%), Scopulariopsis fusca (20.0%) Scopulariopsis brevicaulis (41.7%) and Alternaria alternate (3.3%). The number of fungal species isolated ranged from seven in C.gariepinus to six each in O. niloticus and S. membranaceous. There were no significant differences (p > 0.05) among the three species of fish in the prevalence of infestation. Mould contamination levels were calculated for 1g samples of the fish and the mean fungal colony counts were found to be 2.4x103 for C. gariepinus, 2.1x103 for O. niloticus and 1.7x104 for S. membranaceous.
Conclusion: The presence of these fungi is an indication of the possibility of high level of contamination and deterioration of fish by moulds, and the possible health risks associated with the consumption of smoke-dried fish.

Key words: Fish, Fungi, smoke-dried fish, Sabouraud Dextrose Agar