This study investigated 65 (35 in summer and 30 in winter) smallholder dairy cattle feeds from Free State and Limpopo provinces in South Africa from 2018 to 2019 for fungal contamination and assessed the impacts of seasonal variation on fungal contamination levels, isolation frequency, and diversity. Samples were examined for fungal contamination using macro- and microscopic approaches, and their identities were confirmed by molecular means. A total of 217 fungal isolates from 14 genera, including Aspergillus, Fusarium, and Penicillium, were recovered from feeds from both seasons. The most prevalent fungal species recovered were A. fumigatus and P. crustosum. Mycological analyses showed that 97% of samples were contaminated with one or more fungal isolates, with the summer fungal mean level (6.1 × 103 to 3.0 × 106 CFU/g) higher than that of feeds sampled during winter (mean level: 1.1 × 103 to 4.1 × 105 CFU/g). Independent sample t-test revealed that the isolation frequencies of the genera Aspergillus and Fusarium were significantly (p ≤ 0.05) higher in summer than winter, while Penicillium prevalence in both seasons was not statistically (p > 0.05) different. Furthermore, the Shannon–Weiner diversity index (H′) revealed a higher fungal diversity in summer (H′ = 2.8) than in winter (H′ = 2.1). This study on fungal contamination could be used for future fungal control and mycotoxin risk management in South Africa.

This study evaluated the impact of seasonal and geographical variations on the toxigenicity of Aspergillus and Fusarium strains previously isolated from smallholder dairy cattle feeds and feedstuffs sampled during summer and winter in the Free State and Limpopo provinces of South Africa (SA). In total, 112 potential toxigenic fungal species were obtained and determined for their capability to produce mycotoxins on solid Czapek Yeast Extract Agar (CYA); followed by liquid chromatography-mass spectrometry (LC-MS/MS) analysis. Our result revealed that 41.96% of the fungal species produced their respective mycotoxins, including aflatoxin B1 (AFB1), aflatoxin B2 (AFB2), and zearalenone (ZEN), with higher levels of AFB1 (0.22 to 1045.80 µg/kg) and AFB2 (0.11 to 3.44 µg/kg) produced by fungal species isolated from summer samples than those in winter [(0.69 to 14.44 µg/kg) and (0.21 to 2.26 µg/kg), respectively]. The same pattern was also observed for AFB1 and AFB2 in Limpopo (0.43 to 1045.80 µg/kg and 0.13 to 3.44 µg/kg) and Free State (0.22 to 576.14 µg/kg and 0.11 to 2.82 µg/kg), respectively. More so, ZEN concentrations in summer (7.75 to 97.18 µg/kg) were higher than in winter (5.20 to 15.90 µg/kg). A similar observation was also noted for ZEN in Limpopo (7.80 to 97.18 µg/kg) and Free State (5.20 to 15.90 µg/kg). These findings were confirmed via Welch and Brown-Forsythe tests with significantly (p ≤ 0.05) higher mycotoxin levels produced by fungal strains obtained in samples during summer than those in winter. In contrast, the concentrations of mycotoxins produced by the fungal species from both provinces were not significantly (p > 0.05) different.

The use of medicinal plants for the treatment of diseases, including cancer, is acknowledged and accepted in many African nations. Heavy metal contamination of plant materials poses a potential health risk, particularly for populations that are already vulnerable. This study determines the levels of heavy metals in medicinal plant samples used for treatment of skin cancer and evaluate the health risk caused by heavy metals to the adult population in Pretoria, South Africa using inductively coupled plasma mass spectrometry (ICP-MS). The concentrations of metals were as follows; As (<0.2 – 1.04±0.026), Cd (0.02 ±0.00026 – 0.167±0.006), Pb (0.38 ±0.01 – 2.27±0.05), Cr (5.31±0.21– 26.9 ±3.96) mg/kg, and Hg which were lesser than 0.02 mg/kg. The mean concentrations of all analyzed heavy metals are above permissible limit except for Hg which are lower than the permissible limit. The Hazard Quotient (THQ) was less than 1 for all the heavy metals, suggesting that there are no obvious non-carcinogenic health risks associated with the consumption of these medicinal plants for now even though the prolonged use may result in health risks. The ingestion route was identified as the primary contributor to the overall risk by the health index (HI) values in the present study, which were more than 1, indicating that the combined effects of the heavy metal contaminants present in a particular herbal preparation pose health risk in the long term. Our findings support the need for close monitoring of potential heavy metal concentrations in medicinal plants given to patients from herbal shops.

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