Invisible contaminants in staple foods are posing a serious but often overlooked threat to public health and food security across Africa. Researchers at the University of Johannesburg (UJ), within the Department of Biotechnology and Food Technology, are shedding new light on the scale of this challenge while developing innovative solutions to reduce exposure and strengthen food systems.
The findings reveal alarming levels of mycotoxin contamination in commonly consumed staple foods, raising fresh concerns about food safety and public health. The study, led by Professor Patrick Njobeh, identified recurring contamination in maize, groundnuts and other staples sourced from both commercial supply chains and smallholder farming communities.
Using advanced laboratory analysis, the researchers detected significant levels of aflatoxins and fumonisins in multiple food and feed samples. In several study sites, contamination exceeded recommended safety thresholds, with the highest levels associated with poorly stored grains and high-humidity conditions. The findings point to urgent gaps in post-harvest handling and storage practices as well as detection of these hazards in food and feed, and signal the need for strengthened monitoring, mitigation strategies and policy intervention to protect vulnerable consumers.
A breakthrough in the programme is the discovery that multiple mycotoxins frequently occur together in single food and feed samples, compounding health risks far beyond what single-toxin assessments suggest. This simultaneous exposure poses a serious threat to vulnerable groups, particularly children and communities that depend heavily on maize-based diets. By integrating high-precision laboratory data with detailed dietary consumption surveys, the UJ team and partnering institutions have shown that chronic exposure levels in some communities may significantly elevate the risk of long-term conditions, including liver diseases and weakened immune function.
The research has also pinpointed clear pressure points along the food value chain. Poor post-harvest handling, insufficient drying and inadequate storage infrastructure consistently correlate with higher contamination levels. Crucially, pilot mitigation trials demonstrate that relatively low-cost interventions, improved storage systems and better grain management practices along with early detection, can dramatically reduce fungal growth and toxin production. The findings not only expose the scale of the risk but also provide practical, scalable solutions.
“Mycotoxin exposure is not a distant scientific concern confined to laboratories, it is a daily reality in the diets of many communities,” says Prof Njobeh. “What our research makes clear is that the risk is measurable, significant and preventable. The science points directly to where interventions are most effective. With targeted technologies, improved storage practices and informed awareness, exposure levels can be substantially reduced.”
Beyond its laboratory advances, the programme is building critical national capacity. Postgraduate students are being trained in advanced analytical platforms and quantitative risk assessment modelling, equipping a new generation of scientists with scarce and highly specialised skills in food safety and exposure science. By linking rigorous laboratory data with policy-focused research, the team is generating the kind of evidence required to strengthen food safety regulations and modernise monitoring systems.
Prof Njobeh adds, “The co-exposure patterns we are documenting fundamentally challenge how risk is currently assessed. Regulatory frameworks often evaluate toxins in isolation, yet our data show that consumers are exposed to multiple contaminants simultaneously. This demands integrated risk models and a more responsive regulatory approach.”
He concluded: “Our aim is simple. The science must move beyond publications and into practice. If our data can help improve storage systems, strengthen regulations or reduce exposure in vulnerable communities, then the research is doing what it should. Food safety sits at the intersection of health, agriculture and economic stability and universities have a responsibility to contribute solutions that are practical, evidence-based and socially relevant.”
