Abstract
M.Tech.
A study to determine the occurrence of fungi and their mycotoxins in rural food and
their effect on human health was carried out at N’wamitwa (Tzaneen), a rural area of
Limpopo province (South Africa). Fifty-eight maize and twenty-nine bambara nuts
samples were collected from selected house holds and taken to the storage facilities of
the Food, Environment and Health research group (FEHRG) laboratory at the
University of Johannesburg for analysis.
The samples were analysed for moisture content, fungal infestation, mycotoxin
contamination and their toxicity. The moisture content of the samples were at a range
of 3-20% moisture. Fungi which included species of the genus Aspergillus, Fusarium
and Penicillium were detected at all moisture ranges but more dominant in samples
with higher moisture levels. Fungi in this study were able to produce mycotoxins
which included deoxynivalenol (DON), zearelenone (ZEA), aflatoxins (AFs), T2-
toxin, fumonisins (FBs), ochratoxin A (OTA) and citrinin. The most dominant toxins
in maize samples quantified by VICAM were AFs followed by DON, FBs and lastly
ZEA and in bambara nuts were FBs followed by DON, AFs and ZEA. HPLC was
able to detect higher concentrations of FBs than VICAM.
The toxins were then tested for their toxicity using human lymphocytes and the most
toxic was DON followed by AFs, FBs and lastly ZEA. Three vials of the same toxin
with different concentrations, one with the highest and others with the middle and the
lowest concentrations were used to treat the human lymphocytes.