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

In Vitro and In Vivo Analysis of Ochratoxin A-Derived Glucuronides and Mercapturic Acids as Biomarkers of Exposure

Ochratoxin A (OTA) is a widespread food contaminant, with exposure estimated to range from 0.64 to 17.79 ng/kg body weight (bw) for average consumers and from 2.40 to 51.69 ng/kg bw per day for high consumers. Current exposure estimates are, however, associated with considerable uncertainty. While biomarker-based approaches may contribute to improved exposure assessment, there is yet insufficient data on urinary metabolites of OTA and their relation to external dose to allow reliable estimates of daily intake. This study was designed to assess potential species differences in phase II biotransformation in vitro and to establish a correlation between urinary OTA-derived glucuronides and mercapturic acids and external exposure in rats in vivo. In vitro analyses of OTA metabolism using the liver S9 of rats, humans, rabbits and minipigs confirmed formation of an OTA glucuronide but provided no evidence for the formation of OTA-derived mercapturic acids to support their use as biomarkers. Similarly, OTA-derived mercapturic acids were not detected in urine of rats repeatedly dosed with OTA, while indirect analysis using enzymatic hydrolysis of the urine samples prior to LC–MS/MS established a linear relationship between urinary glucuronide excretion and OTA exposure. These results support OTA-derived glucuronides but not mercapturic acids as metabolites suitable for biomonitoring

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

Indigenous Food Yam Cultivation and Livelihood Practices in Cross River State, Nigeria

Yam production, processing, distribution, and marketing processes are underpinned by socio-cultural beliefs shaped by ritual practices and indigenous wisdom. We used semi-structured interviews, public meetings, keen observation, local informants, and a review of secondary materials to assess local indigenous understanding of interconnected perspectives of yam farming processes, socio-cultural perspectives, and livelihood practices in communities in southern Nigeria. Our findings revealed that over 90% of farmers depend on experiences of adjusting to seasonal challenges, storage practices, and fertility enhancement. Cultural beliefs and spiritual practices pervade farmers’ social attitudes to improving farming operations. Almost 70% of yam producers are aged 60 years and above and depend on crude tools and traditional methods of land management and production process, even though the modern and innovative farming methods and practices are limited. Farmers respond to the poor public support system of extension services by informal networking and local associational relationships with diverse schemes to support and encourage members. Government and organizations should take advantage of these informal structures to empower farmers through micro-credits, education, information, training, supervision, and mechanization. Different groups of actors organized into formal social structures like cooperatives will take advantage of bulk buying, selling, transportation, access fundings, information, education, and training from public and non-governmental institutions. The study findings have demonstrated that the socio-economic structure of the Obudu community has developed extensively on account of decades of yam production and processing, supporting chains of a livelihood network, entrepreneurship, and relationships of mutual cooperation and co-existence

Mycotoxin toxicity and residue in animal products: Prevalence, consumer exposure and reduction strategies – A review.

Mycotoxin residues are transferred from feed to animal products, yet, less attention has been paid to it in developing countries like Nigeria, India, Mexico etc. There is a need to find alternative alleviation material for reducing the impact of mycotoxin. This review is meant to elucidate different additives that can reduce mycotoxin residue in animal products in the world, especially in developing countries. . There is evidence of relationship between mycotoxin residue in breast milk of nursing mothers and mycotoxin exposure through crop and animal product (egg and milk) intake, especially in Asia, Africa, Middle East, Latin America, and some parts of Europe. Younger livestock tends to have more toxin residues in their tissue compared to older animals. Grazing animal are also exposed to mycotoxin intake which corresponds to high level of mycotoxins in their products including meat and milk. . This review shows that phytogenic, probiotic, and prebiotic additives can decrease mycotoxin residues in milk, eggs, meat liver and other tissues of livestock. Specifically, bentonites, difructose anhydride III, yeast (Trichosporon mycotoxinivorans), Bacillus spp., or their biodegradable products can reduce mycotoxin residue in animal products. In addition, Ally isothiocyanates from mustard seed were able to mititgate mycotoxins in silo-simulated system. Evidence shows that there are now low-cost, accessible, and eco-friendly feed additives, which could alleviate the effect of mycotoxin in feed and food. There is a need for aggressive public awareness and farmers’ education on the prevalence, and danger caused by mycotoxins as well as possible additives that can reduce toxin absorption into animal products