The status of Fusarium mycotoxins in Sub-Saharan Africa : a review of emerging trends and post-harvest mitigation strategies towards food control

Fusarium fungi are common plant pathogens causing several plant diseases. The presence of these molds in plants exposes crops to toxic secondary metabolites called Fusarium mycotoxins. The most studied Fusarium mycotoxins include fumonisins, zearalenone, and trichothecenes. Studies have highlighted the economic impact of mycotoxins produced by Fusarium. These arrays of toxins have been implicated as the causal agents of wide varieties of toxic health effects in humans and animals ranging from acute to chronic. Global surveillance of Fusarium mycotoxins has recorded significant progress in its control; however, little attention has been paid to Fusarium mycotoxins in sub-Saharan Africa, thus translating to limited occurrence data. In addition, legislative regulation is virtually non-existent. The emergence of modified Fusarium mycotoxins, which may contribute to additional toxic effects, worsens an already precarious situation. This review highlights the status of Fusarium mycotoxins in sub-Saharan Africa, the possible food processing mitigation strategies, as well as future perspectives

Occurrence of Fusarium mycotoxins in cereal crops and processed products (ogi) from Nigeria

In Nigeria, maize, sorghum, and millet are very important cash crops. They are consumed on a daily basis in different processed forms in diverse cultural backgrounds. These crops are prone to fungi infestation, and subsequently may be contaminated with mycotoxins. A total of 363 samples comprising of maize (136), sorghum (110), millet (87), and ogi (30) were collected from randomly selected markets in four agro-ecological zones in Nigeria. Samples were assessed for Fusarium mycotoxins contamination using a multi-mycotoxin liquid chromatography-tandem mass spectrometry (LC-MS/MS) method. Subsequently, some selected samples were analysed for the occurrence of hidden fumonisins. Overall, 64% of the samples were contaminated with at least one toxin, at the rate of 77%, 44%, 59%, and 97% for maize, sorghum, millet, and ogi, respectively. Fumonisins were the most dominant, especially in maize and ogi, occurring at the rate of 65% and 93% with mean values of 935 and 1128 mu g/kg, respectively. The prevalence of diacetoxyscirpenol was observed in maize (13%), sorghum (18%), and millet (29%), irrespective of the agro-ecological zone. Other mycotoxins detected were deoxynivalenol, zearalenone, and their metabolites, nivalenol, fusarenon-X, HT-2 toxin, and hidden fumonisins. About 43% of the samples were contaminated with more than one toxin. This study suggests that consumption of cereals and cereal-based products, ogi particularly by infants may be a source of exposure to Fusarium mycotoxins

Awareness and prevalence of mycotoxin contamination in selected Nigerian fermented foods

Fermented food samples (n = 191) including maize gruel (ogi), sorghum gruel (ogi-baba), melon seed (ogiri), locust bean (iru) and African oil bean seed (ugba) from Southwest Nigeria were quantified for 23 mycotoxins, including aflatoxin B-1 (AFB(1)), fumonisin B-1 (FB1), and sterigmatocystin (STE) using liquid chromatography-tandem mass spectrometry. The practices, perceived understanding and health risks related to fungal and mycotoxin contamination amongst fermented food sellers was also established. Data obtained revealed that 82% of the samples had mycotoxins occurring singly or in combination. FB1 was present in 83% of ogi-baba samples, whereas 20% of ugba samples contained AFB(1) (range: 3 to 36 mu g/kg) and STE was present in 29% of the ogi samples. In terms of multi-mycotoxin contamination, FB1 + FB2 + FB3 + STE + AFB(1) + alternariol + HT-2 co-occurred within one sample. The awareness study revealed that 98% of respondents were unaware of mycotoxin contamination, and their education level slightly correlated with their level of awareness (p < 0.01, r = 0.308). The extent to which the analyzed mycotoxins contaminated these food commodities, coupled with the poor perception of the population under study on fungi and mycotoxins, justifies the need to enact fungal and mycotoxin mitigation strategies along the food chain

The Status of Fusarium Mycotoxins in Sub-Saharan Africa: A Review of Emerging Trends and Post-Harvest Mitigation Strategies towards Food Control

Fusarium fungi are common plant pathogens causing several plant diseases. The presence of these molds in plants exposes crops to toxic secondary metabolites called Fusarium mycotoxins. The most studied Fusarium mycotoxins include fumonisins, zearalenone, and trichothecenes. Studies have highlighted the economic impact of mycotoxins produced by Fusarium. These arrays of toxins have been implicated as the causal agents of wide varieties of toxic health effects in humans and animals ranging from acute to chronic. Global surveillance of Fusarium mycotoxins has recorded significant progress in its control; however, little attention has been paid to Fusarium mycotoxins in sub-Saharan Africa, thus translating to limited occurrence data. In addition, legislative regulation is virtually non-existent. The emergence of modified Fusarium mycotoxins, which may contribute to additional toxic effects, worsens an already precarious situation. This review highlights the status of Fusarium mycotoxins in sub-Saharan Africa, the possible food processing mitigation strategies, as well as future perspectives

A survey of South African commercial feed grade maize for mycotoxins with particular reference to fumonisins using different analytical techniques

M.Tech.Maize (Zea may) is the third most important cereal in the world serving various purpose of economic importance especially as staple diet to the Africans and as a major component of animal feed. Unfortunately, this commodity serves as a suitable substrate for pest and fungi development which may result in the production of mycotoxins. Mycotoxins are secondary metabolites of varying chemical structures produced by filamentous fungi, which may contaminate agricultural commodities either in the field or at storage. Mycotoxins have been implicated to cause several diseases in humans and animals ranging from acute to chronic. This study was designed to determine and quantify the occurrence and levels of mycotoxins in South African feed grade commercial maize. A total of 40 commercial feed grade maize samples were randomly sampled from two factory sites (Factory A and Factory B) of a commercial feed company source from known South African maize producers. The samples were screened for fungi using the conventional method while the mycotoxin screening and quantification was done by thin layer chromatography (TLC) and high performance liquid chromatography (HPLC). In addition to TLC and HPLC, VICAM/HPLC, VICAM/fluorometer, enzyme linked immuno-sorbent assay (ELISA) and lateral flow method were used for determination and quantification of fumonisins. The mycological investigation revealed the occurrence of several fungal species of Fusarium, Aspergillus and Penicillium with Fusarium being the most prevalent (100%). Among the Fusarium spp. were F. verticillioides, F. proliferatum, F. oxysporum and F. graminearum, F. subglutinans, F. chlamydosporum, F. solani, F. poae and F. dimerum. Fusarium verticillioides and F. proliferatum had the highest incidence rate of 89% and 73%, respectively, followed by F. oxysporum (65%) and F. graminearum (48%). The rate of occurrence of A. fumigatus, A. flavus and Penicillium spp. were 45%, 43% and 38%, respectively. Further analysis on the isolated fungal strains proved that over 50% of the fungal spp. were toxigenic. Mycotoxicological study on the samples revealed that the samples were contaminated with fumonisins (FB), aflatoxins B (AFB), ochratoxin A (OTA) and zearalenone (ZEA) on TLC. Mycotoxins levels in the samples were confirmed on HPLC, with the levels ranging from 0.064-1.035 ppm for FB, 0-0.762 ppm for iii AFB, 0-0.194 ppm for OTA and 0-0.135 ppm for ZEA. There was no significance difference on mycotoxin concentration in the feed grade sample between the two factory sites. Results obtained from the VICAM methods, ELISA and lateral flow method for FB determination showed 100% incidence rate of the feed grade maize samples similar to that observed on HPLC. Although ELISA (0.190-2.450 ppm) and lateral flow method (0.350-2.700 ppm) showed higher concentration of FB compared to HPLC (0.064-1.035 ppm), recovery analysis on sample using lateral flow gave high value (85%) comparable to HPLC. Further analyses were performed to determine the cytotoxic potential of the feed grade maize samples using the fumonisin fraction (FFraction). The data obtained showed that the feed grade maize extracts were toxic on human peripheral blood mononuclear cells (HPBMC) and the degree of effect on the cells is dependent on the concentration of FB and the duration of exposure. However using oneway ANOVA to determine the effect of different concentration (volumes) of toxin and time of exposure on HPBMC in this study, it was observed that there was no significant difference regardless of the concentration and time

Mycotoxin Occurrence, Exposure and Health Implications in Infants and Young Children in Sub-Saharan Africa: A Review

Infants and young children (IYC) remain the most vulnerable population group to environmental hazards worldwide, especially in economically developing regions such as sub-Saharan Africa (SSA). As a result, several governmental and non-governmental institutions including health, environmental and food safety networks and researchers have been proactive toward protecting this group. Mycotoxins, toxic secondary fungal metabolites, contribute largely to the health risks of this young population. In SSA, the scenario is worsened by socioeconomic status, poor agricultural and storage practices, and low level of awareness, as well as the non-establishment and lack of enforcement of regulatory limits in the region. Studies have revealed mycotoxin occurrence in breast milk and other weaning foods. Of concern is the early exposure of infants to mycotoxins through transplacental transfer and breast milk as a consequence of maternal exposure, which may result in adverse health effects. The current paper presents an overview of mycotoxin occurrence in foods intended for IYC in SSA. It discusses the imperative evidence of mycotoxin exposure of this population group in SSA, taking into account consumption data and the occurrence of mycotoxins in food, as well as biomonitoring approaches. Additionally, it discusses the health implications associated with IYC exposure to mycotoxins in SSA

Mycotoxin Regulatory Status in Africa: A Decade of Weak Institutional Efforts

Food safety problems are a major hindrance to achieving food security, trade, and healthy living in Africa. Fungi and their secondary metabolites, known as mycotoxins, represent an important concern in this regard. Attempts such as agricultural, storage, and processing practices, and creation of awareness to tackle the menace of fungi and mycotoxins have yielded measurable outcomes especially in developed countries, where there are comprehensive mycotoxin legislations and enforcement schemes. Conversely, most African countries do not have mycotoxin regulatory limits and even when available, are only applied for international trade. Factors such as food insecurity, public ignorance, climate change, poor infrastructure, poor research funding, incorrect prioritization of resources, and nonchalant attitudes that exist among governmental organisations and other stakeholders further complicate the situation. In the present review, we discuss the status of mycotoxin regulation in Africa, with emphasis on the impact of weak mycotoxin legislations and enforcement on African trade, agriculture, and health. Furthermore, we discuss the factors limiting the establishment and control of mycotoxins in the region

The Dioscorea genus (yam) — an appraisal of nutritional and therapeutic potentials

The quest for a food secure and safe world has led to continuous effort toward improvements of global food and health systems. While the developed countries seem to have these systems stabilized, some parts of the world still face enormous challenges. Yam (Dioscorea species) is an orphan crop, widely distributed globally; and has contributed enormously to food security especially in sub-Saharan Africa because of its role in providing nutritional benefits and income. Additionally, yam has non-nutritional components called bioactive compounds, which offer numerous health benefits ranging from prevention to treatment of degenerative diseases. Pharmaceutical application of diosgenin and dioscorin, among other compounds isolated from yam, has shown more prospects recently. Despite the benefits embedded in yam, reports on the nutritional and therapeutic potentials of yam have been fragmented and the diversity within the genus has led to much confusion. An overview of the nutritional and health importance of yam will harness the crop to meet its potential towards combating hunger and malnutrition, while improving global health. This review makes a conscious attempt to provide an overview regarding the nutritional, bioactive compositions and therapeutic potentials of yam diversity. Insights on how to increase its utilization for a greater impact are elucidated