Assessment of aflatoxin-producing fungal strains in flour samples sold at kalerwe market.

Abstract

Fungi are an integral part of the natural environment and, therefore, play many roles in relation to food: some fungi are used in food production, some are food sources themselves, and some are agents of food spoilage. Mycotoxins are toxic secondary metabolites with a potential to cause adverse effects in humans and animals. Aflatoxin are toxic and carcinogenic secondary metabolites which contaminate food and feed and threaten human and animal health. They are produced by Aspergillus species such as; A. parasiticus, A. flavus, A. nomius and many others. In this research the aflatoxin producing fungal strains were assessed in four sample flours collected from Kalerwe market. The results indicated a high strain frequency of the L strain of A. flavus with 79.9% of the isolates; S strain with 7.1%; A. tamari with 8.2% and A. parasiticus with 4.8% frequency of the isolates. Despite that the four flours had a characteristic high frequency of L strain they each had varied distribution of the other strains (parasiticus, tamari and S strain); this was also confirmed by the Kruskal Walis test which indicated a difference in the concentration of aflatoxin in the flour samples. This was further elaborated by the fact that the S stain and A. parasiticus produce more aflatoxin than the other two and also that the high frequency of L strain wasn’t directly proportional to the aflatoxin concentration since it contains the L negative strain which does not produce aflatoxin. It is imperative that the people involved at each stage of production of agricultural produce ensure proper handling and management of the produce and equipment to minimize further contamination.