Maize is one of the major staple foods of Sub-Saharan Africa and is consumed as whole or dehulled grain. In this region, where the environmental conditions favour fungal growth and mycotoxin production, the majority of the population are subsistence consumers who, unfortunately, have little or no access to mycotoxin testing of their food. In an attempt to develop feasible reduction strategies in dietary mycotoxin exposure of the population, a three-factorial design experiment was conducted to examine and compare the efficacy of hand sorting, flotation, dehulling and combinations thereof in removing naturally occurring aflatoxins, fumonisins, nivalenol, deoxynivalenol and alternariol in shelled white maize. Regression analysis was used to determine the significant (p < 0.05) process variables on the removal of mycotoxins from the maize. Results from this experiment indicated that hand sorting had the greatest effect on mycotoxin removal, while flotation yielded the least effect. In particular hand sorting left < 6% of aflatoxin B1 and < 5% of fumonisin B1. Based on these results, hand sorting of maize grains is being recommended as a last line of defence against mycotoxin exposure among subsistence consumers.

This study assessed knowledge, attitude, and practices (KAP) of the public in Malawi on issues related to molds in foodstuffs. A survey involving structured questionnaire was conducted with 805 respondents from seven districts of Malawi. Descriptive statistics, t tests, and analyses of variance were calculated. A majority of respondents recognized that molds were dangerous to human health (88%); however, about 50% of respondents were not informed that mold toxins are thermally stable and that they are not destroyable by normal cooking processes. About 33% of the respondents asserted that they buy moldy maize, while approximately 20% of respondents reported that they consume moldy fruits having discarded moldy fraction. There were significant differences in knowledge scores among different demographic groups. Females had significantly (p < 0.05) lower knowledge scores on issues related to molds in foods. Additionally, the respondent's location had a significant effect. However, respondent's education had subtle effect on knowledge score and the overall population's knowledge score was generally low (3.55 ± 1.32 score out of 9). Results of the study underline the need to raise public's knowledge about health risks associated with spoilage molds in food and prevention and management options.

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Following the discovery of aflatoxins in the early 1960s, there have been many studies leading to the uncovering of many mycotoxins and the understanding of associated health effects in animals and humans. Consequently, there has been a global increase in the number of countries with mycotoxin regulations in foods. However, many African countries have only regulations for aflatoxins (or a few other mycotoxins) in specific foods, or no regulations at all. This paper critically reviews the challenges thwarting the establishment of mycotoxin regulations and their impacts on human dietary mycotoxin exposure in Africa. Mycotoxin regulatory limits for different countries are compared with mycotoxin tolerable daily intakes established by international food safety bodies taking into account consumption patterns. The agrarian setup, food insecurity, and mycotoxin analytical challenges in African countries are discussed; and more feasible mycotoxin dietary exposure reduction strategies are proposed.

This study investigated the diversity of fungal metabolites in maize across four agro-ecological zones of Malawi. A total of 90 maize samples (for human consumption), collected from farmsteads, were analysed for 235 fungal metabolites using liquid chromatography-tandem mass spectrometry. A total of 65 metabolites were found in the samples. 75% of samples from the hottest agro-ecological zone contained either aflatoxins, fumonisins, deoxynivalenol, zearalenone; or a combination thereof in levels exceeding European Union (EU) maximum levels, whereas the related fraction was only 17% in the cool temperature zone. Aflatoxins, citrinin, 3-nitropropionic acid, monocerin and equisetin were most prevalent and in higher levels in samples from hot agro-ecological zones, whereas deoxynivalenol, nivalenol, zearalenone and aurofusarin were most prevalent in cool agro-ecologies. On the basis of per-capita maize consumption, estimated daily intakes for all samples from hot ecologies were well above the JECFA's provisional maximum tolerable daily intake (PMTDI) of 2.0 μg/kg body weight (bw)/day for fumonisins, whereas the PMTDI of 1.0 μg/kg bw/day for deoxynivalenol was exceeded in relatively more (90%) samples from the cool highlands than the other zones. These results demonstrate the influence of micro-climatic conditions on mycotoxin prevalence patterns and underscores the need for development of agro-ecological specific mycotoxin dietary exposure management strategies.

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We report an unusual aflatoxin profile in maize and groundnuts from Malawi, with aflatoxin G1 found routinely at equal or even higher levels than aflatoxin B1. Aflatoxin B1 (AFB1) ratio in a contaminated sample is generally greater than 50% of total aflatoxin (sum of aflatoxin B1, B2, G1, and G2). In Malawi, the aflatoxin occurrence ratios were determined by examining LC-MS/MS and HPLC fluorescence detection (FLD) data of 156 naturally contaminated raw maize and 80 groundnut samples collected in 2011 and 2012. Results showed that natural aflatoxin occurrence ratio differed. In 47% of the samples, the concentration of AFG1 was higher than that of AFB1. The mean concentration percentages of AFB1/AFB2/AFG1/AFG2 in reference to total aflatoxins were found to be 47:5:43:5%, respectively. The AFG1 and AFB1 50/50 trend was observed in maize and groundnuts and was consistent for samples collected in both years. If the AFB1 measurement was used to check compliance of total aflatoxin regulatory limit set at 10, 20, 100, and 200 μg/kg with an assumption that AFB1≥50% of the total aflatoxin content, 8, 13, 24, and 26% false negative rates would have occurred respectively. It is therefore important for legislation to consider total aflatoxins rather than AFB1 alone.

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.