The prevalence of fungi in traditionally smoked Nile tilapia (Oreochromis niloticus) at selected markets in Kampala, Uganda.

Abstract

This study was aimed at isolating and identifying the fungi associated with traditionally smoked O. niloticus contamination in Kampala. A total of 12 samples were purchased, four from each of the three markets (Wandegeya, Karelwe and Bwaise) in Kampala city, Uganda. The samples were aseptically processed and cultured for fungal isolation using Potato Dextrose Agar. Isolates were identified using macroscopic and microscopic characteristics, and comparison with species in the fungal atlas (Ochei & Kolhatkar, 2000). Eight different fungi were found to be associated with the samples. Aspergillus sp. (21.43%), Yeasts (21.43%), Trichophyton sp. (14.29%), Penicillium sp. (14.29%) were the dominant fungi isolated, while Mucor sp. (7.14%) Trichoderma sp. (7.14%), Rhizopus sp. (7.14%), and Fusarium sp. (7.14%) occurred less frequently. It was observed that Aspergillus sp. and Yeasts had the highest rate of occurrence among the isolated fungi. The moisture content of the traditionally smoked O. niloticus ranged from 29.6 – 40% while its fungal load ranged from 1.7 × 106 to 5.1 × 106 CFU/g with a significant difference in the fungal load of different markets (p< 0.05). The correlation between moisture content and CFU was 0. 902.The presence of mycotoxin producing species such as Aspergillus sp., Penicillium sp. and Fusarium sp. in the samples showed that the fish sold in sampled markets in Kampala district could be a threat to the health of the consumers. It is therefore recommended that the fish should be dried and maintained at about 10 % moisture content to reduce fungal growth. The findings of the study are useful in developing and establishing public health standards as consumption of these fungi exposes the consumers to the probable toxic metabolites produced by the fungi. There is the need to improve on hygiene during processing, storage and distribution of smoked fish in Uganda.