Abstract
D.Tech. (Biomedical technology)
The majority of the South African rural black population remain is exposed to HIV/ AIDS and other chronic diseases, tuberculosis, malaria and cancer. The effect of single and combined mycotoxins on their health and particularly their immune system is unknown and remain of concern as these populations are on daily basis exposed more than one mycotoxin at once. The aim of this study was to evaluate the exposure of South African rural black populations to mycotoxins via animal products in comparison to urban populations and to assess the effect of the major mycotoxins (fumonisin B1 (FB1), aflatoxin B1 (AFB1) and ochratoxin A (OTA)) mostly present in their food on human and animals (pigs) mononuclear cells and by extrapolation, evaluate possibilities of these mycotoxins on the immune system. To achieve this, animal feed and animal products (milk, serum, and tissues) obtained from selected rural and commercial farms in selected areas of South Africa were analysed for fungal and mycotoxins contamination. It was found in this study that almost all of the samples from both areas were contaminated with the major mycotoxin producing fungal strains (Fusarium, Aspergillus and Penicillium spp.) with the most prominent among them being Aspergillus flavus (87%), A. parasiticus (43%), A. niger (69%), A. ochraceus (42%), A. candidus (23%), F. verticillioides (98%) F. graminearum (67%) and P. Verrucosum (48.9%) and in commercial samples A. flavus (98%), A. parasiticus (51%), A. ochraceus (65%), A. niger (31%), A. candidus (21%), F. verticillioides (F. moniliforme) (68%), F. graminearum (43%) and P. verrucosum (7%). While, the three main mycotoxins were also present and contaminated most samples with fumonisins (FBs) 0in rural and commercial samples at 90.6% and 93.3% respectively with respective means values of 10136.4 ppb and 1045.4 ppb. Aflatoxins (AFs) contamination was of 92.0% in rural samples and 96.2% in commercial samples with means concentrations of 168.8 ppb and 294.1 ppb respectively. While 85.4% and 83.7% of rural and commercial samples respectively were contaminated with ochratoxin A (OTA), with mean concentrations of 67.6 ppb and 89.4 ppb respectively. Zearalenone (ZEA) concentrations were of 43.6 ppb in rural samples and 62.7 ppb in commercial samples with respective contamination of 50.6% and 55.3%. In addition, a co-occurrence of fungi and mycotoxins contaminations was found in both rural and commercial samples. It was found that, 50.5% of rural and 53% of commercial samples were contaminated with all four analyzed mycotoxins.
(FBs, AFs, OTA and ZEA), whereas, 81.2% and 79.5% of samples respectively from rural and commercial farms were contaminated with FBs, AFs and OTA mycotoxins simultaneously. The above-obtained results are of significance in this study as they confirm the hypothesis of fungal contamination and mycotoxin co-occurrence in South African feed and their possible combined effects on consumers.