Aflatoxin is considered a “hidden poison” due to its slow and adverse effect on various biological pathways in humans, particularly among children, in whom it leads to delayed development, stunted growth, liver damage, and liver cancer. Unfortunately, the unpredictable behavior of the fungus as well as climatic conditions pose serious challenges in precise phenotyping, genetic prediction and genetic improvement, leaving the complete onus of preventing aflatoxin contamination in crops on post-harvest management. Equipping popular crop varieties with genetic resistance to aflatoxin is key to effective lowering of infection in farmer’s fields. A combination of genetic resistance for in vitro seed colonization (IVSC), pre-harvest aflatoxin contamination (PAC) and aflatoxin production together with pre- and post-harvest management may provide a sustainable solution to aflatoxin contamination. In this context, modern “omics” approaches, including next-generation genomics technologies, can provide improved and decisive information and genetic solutions. Preventing contamination will not only drastically boost the consumption and trade of the crops and products across nations/regions, but more importantly, stave off deleterious health problems among consumers across the globe.

Peanut (Arachis hypogaea L.) is an important crop in Malawi and Zambia. The crop is valued for soil improvement in cereal-based cropping systems, for improving the livelihoods of farming households who consume it and also sell it for cash, and for earning foreign exchange when exported. Research and development efforts have resulted in an increase in both peanut production area and productivity. However, a key challenge that still needs to be solved in these countries is how to produce peanuts with acceptable levels of aflatoxin contamination. Data continues to show that aflatoxin continues to be a problem in both formal and informal trade. As a result, unlike 30 years ago, most of the peanut trade has now shifted to domestic and regional markets that do not restrict the sale of aflatoxin-contaminated peanuts. Impacts of aflatoxin contamination on health and also on the full cost burden of control are not well documented. Technologies are available for mitigating against aflatoxin contamination. The advantages, disadvantages, and gaps associated with these technologies are discussed. Considerable money and effort continues to be invested in Malawi and Zambia into mitigating aflatoxin contamination, but evidence of long-term success is limited. Based on past and current initiatives, the prospects of eliminating aflatoxin in the near future at the household level and in trade are not promising.

A knowledge, attitude and practice (KAP) study was conducted in three districts of Malawi to test whether the training had resulted in increased knowledge and adoption of recommended pre- and post-harvest crop management practices, and their contribution to reducing aflatoxin contamination in groundnut, maize and sorghum. The study was conducted with 900 farmers at the baseline and 624 farmers at the end-line, while 726 and 696 harvested crop samples were collected for aflatoxin testing at the baseline and end-line, respectively. Results show that the knowledge and practice of pre- and post-harvest crop management for mitigating aflatoxin were inadequate among the farmers at the baseline but somewhat improved after the training as shown at the end-line. As a result, despite unfavorable weather, the mean aflatoxin contamination level in their grain samples decreased from 83.6 to 55.8 ppb (p < 0.001). However, it was also noted that increased knowledge did not significantly change farmers’ attitude toward not consuming grade-outs because of economic incentive incompatibility, leaving potential for improving the practices further. This existing gap in the adoption of aflatoxin mitigation practices calls for approaches that take into account farmers’ needs and incentives to attain sustainable behavioral change.

A 3-year comprehensive analysis of aflatoxin contamination in peanut butter was conducted in Zambia, sub-Saharan Africa. The study analyzed 954 containers of 24 local and imported peanut butter brands collected from shops in Chipata, Mambwe, Petauke, Katete, and Nyimba districts and also in Lusaka from 2012 to 2014. For analysis, a sample included six containers of a single brand, from the same processing batch number and the same shop. Each container was quantitatively analyzed for aflatoxin B1 (AFB1) in six replicates by using competitive enzyme-linked immunosorbent assay; thus, aflatoxin contamination level of a given sample was derived from an average of 36 test values. Results showed that 73% of the brands tested in 2012 were contaminated with AFB1 levels >20 μg/kg and ranged up to 130 μg/kg. In 2013, 80% of the brands were contaminated with AFB1 levels >20 μg/kg and ranged up to 10,740 μg/kg. Compared with brand data from 2012 and 2013, fewer brands in 2014, i.e., 53%, had aflatoxin B1 levels >20 μg/kg and ranged up to 1,000 μg/kg. Of the eight brands tested repeatedly across the 3-year period, none consistently averaged ≤20 μg/kg. Our survey clearly demonstrates the regular occurrence of high levels of AF B1 in peanut butter in Zambia. Considering that some of the brands tested originated from neighboring countries such as Malawi, Zimbabwe, and South Africa, the current findings provide a sub-Saharan regional perspective regarding the safety of peanut butter.

Cauliflower (Brassica oleracea var. botrytis subvar. cauliflora) is susceptible to wilt caused by Verticillium dahliae but broccoli (B. oleracea var. italica subvar. cyamosa) is not. Infection of broccoli and cauliflower by a green fluorescent protein-expressing isolate of V. dahliae was examined using epifluorescence and confocal laser-scanning microscopy to follow infection and colonization in relation to plant phenology. Plant glucosinolate, phenolic, and lignin contents were also assayed at 0, 4, 14, and 28 days postinoculation. V. dahliae consistently infected and colonized the vascular tissues of all cauliflower plants regardless of age at inoculation, with the pathogen ultimately appearing in the developing seed; however, colonization decreased with plant age. In broccoli, V. dahliae infected and colonized root and stem xylem tissues of plants inoculated at 1, 2, or 3 weeks postemergence. However, V. dahliae colonized only the root xylem and the epidermal and cortical tissues of broccoli plants inoculated at 4, 5, and 6 weeks postemergence. The frequency of reisolation of V. dahliae from the stems (4 to 22%) and roots (10 to 40%) of mature broccoli plants was lower than for cauliflower stems (25 to 64%) and roots (31 to 71%). The mean level of aliphatic glucosinolates in broccoli roots was 6.18 times higher than in the shoots and did not vary with age, whereas it was 3.65 times higher in cauliflower shoots than in the roots and there was a proportional increase with age. Indole glucosinolate content was identical in both cauliflower and broccoli, and both indole and aromatic glucosinolates did not vary with plant age in either crop. Qualitative differences in characterized glucosinolates were observed between broccoli and cauliflower but no differences were observed between inoculated and noninoculated plants for either broccoli or cauliflower. However, the phenolic and lignin contents were significantly higher in broccoli following inoculation than in noninoculated broccoli or inoculated cauliflower plants. The increased resistance of broccoli to V. dahliae infection was related to the increase in phenolic and lignin contents. Significant differential accumulation of glucosinolates associated with plant phenology may also contribute to the resistant and susceptible reactions of broccoli and cauliflower, respectively, against V. dahliae.