Rural Subsistence Maize Farming in South Africa: Risk Assessment and Intervention models for Reduction of Exposure to Fumonisin Mycotoxins

Abstract

Maize is a staple crop in rural subsistence regions of southern Africa, is mainly produced for direct household consumption and is often contaminated with high levels of mycotoxins. Chronic exposure to mycotoxins is a risk factor for human diseases as it is implicated in the development of cancer, neural tube defects as well as stunting in children. Although authorities may set maximum levels, these regulations are not effective in subsistence farming communities. As maize is consumed in large quantities, exposure to mycotoxins will surpass safe levels even where the contamination levels are below the regulated maximum levels. It is clear that the lowering of exposure in these communities requires an integrated approach. Detailed understanding of agricultural practices, mycotoxin occurrence, climate change/weather patterns, human exposure and risk are warranted to guide adequate intervention programmes. Risk communication and creating awareness in affected communities are also critical. A range of biologically based products for control of mycotoxigenic fungi and mycotoxins in maize have been developed and commercialised. Application of these methods is limited due to a lack of infrastructure and resources. Other challenges regarding integration and sustainability of technological and community-based mycotoxin reduction strategies include (i) food security, and (ii) the traditional use of mouldy maize.

Detoxification of the Fumonisin Mycotoxins in Maize: An Enzymatic Approach

“…In the current study, the “low” FB contaminated maize contained FB levels below the regulatory maximum levels for fumonisins in maize (total FB 1 and FB 2 4000 µg/kg) set by the Codex Alimentarius Commission [38], while the high FB contaminated samples exceeded that. These maize batches were therefore ideal to evaluate the newly designed FumD FB reduction method, which could find application in maize subsistence farming communities where exposure to high levels of FB is the norm on a daily basis [37,39]. Of interest is that the bulk of HFB 1 resides into the aqueous phase, which will further minimize exposure to, not only FB 1 , but also to the less toxic breakdown product, HFB 1 .…”

The use of plant extracts and their phytochemicals for control of toxigenic fungi and mycotoxins

“…Chemical methods involve the use of chemicals such as ammonia, sodium hydroxide, hydrochloric acid, butylated hydroxytoluene, butylated hydoxyxyanisole and oltipraz to decontaminate mycotoxins ( Galvano et al., 2001 ; Karlovsky et al., 2016 ; Čolović et al., 2019 ). In addition to their inefficacy in decontamination of mycotoxins, their long-term extreme use is still limited due to their residual toxic product/s, public health and environmental concerns ( Abdel-Fattah et al., 2018 ; Alberts et al., 2019 ; Sadhasivam et al., 2019 ; Meng et al., 2020 ) coupled with the interference with nutrients and organoleptic properties of food and feed ( Celik, 2020 ).…”

“…Botanicals are generally regarded as environmentally friendly and safer alternative sources of bioagents for the control of fungi and mycotoxins in food and feed ( Iram et al., 2016 ; Adebo et al., 2020 ; Prakash et al., 2020 ). They are more affordable as opposed to other materials used for the same purpose, they provide a synergistic approach as protectants of fungal/mycotoxin contamination and further stimulate pathways that elicit the natural defence systems in plant tissues ( da Cruz Cabral et al., 2013 ; Alberts et al., 2019 ; Gacem et al., 2020 ; Meng et al., 2020 ). They contain various phytochemicals with pharmacological properties against various diseases.…”

Phlobaphenes modify pericarp thickness in maize and accumulation of the fumonisin mycotoxins

“…The chronic exposure to mycotoxins represents a critical factor for human health, especially in the case of malnourished populations in low income countries 23 . In fact in rural subsistence regions of Southern Africa, where maize is the major staple crop, even when the level of mycotoxin contamination is under the maximum level, the exposure to mycotoxin can exceed the safe levels because of the undiversified maize-based diet.…”

“…In fact in rural subsistence regions of Southern Africa, where maize is the major staple crop, even when the level of mycotoxin contamination is under the maximum level, the exposure to mycotoxin can exceed the safe levels because of the undiversified maize-based diet. Maize cultivated in these areas is often prone to pre-and post-harvest mycotoxin contamination because of poor agricultural practices such as sowing untreated seeds from the previous season, late planting, incomplete drying of grains, or long storage of crops in facilities without adequate aeration, moisture and temperature control 23 .…”