Mycotoxin problem in Africa: current status, implications to food safety and health and possible management strategies.
ABSTRACT Mycotoxins are toxic secondary metabolites of fungal origin and contaminate agricultural commodities before or under post-harvest conditions. They are mainly produced by fungi in the Aspergillus, Penicillium and Fusarium genera. When ingested, inhaled or absorbed through the skin, mycotoxins will cause lowered performance, sickness or death on humans and animals. Factors that contribute to mycotoxin contamination of food and feed in Africa include environmental, socio-economic and food production. Environmental conditions especially high humidity and temperatures favour fungal proliferation resulting in contamination of food and feed. The socio-economic status of majority of inhabitants of sub-Saharan Africa predisposes them to consumption of mycotoxin contaminated products either directly or at various points in the food chain. The resulting implications include immuno-suppression, impaired growth, various cancers and death depending on the type, period and amount of exposure. A synergistic effect between mycotoxin exposure and some important diseases in the continent such as malaria, kwashiorkor and HIV/AIDS have been suggested. Mycotoxin concerns have grown during the last few decades because of their implications to human and animal health, productivity, economics of their management and trade. This has led to development of maximum tolerated limits for mycotoxins in various countries. Even with the standards in place, the greatest recorded fatal mycotoxin-poisoning outbreak caused by contamination of maize with aflatoxins occurred in Africa in 2004. Pre-harvest practices; time of harvesting; handling of produce during harvesting; moisture levels at harvesting, transportation, marketing and processing; insect damage all contribute to mycotoxin contamination. Possible intervention strategies include good agricultural practices such as early harvesting, proper drying, sanitation, proper storage and insect management among others. Other possible interventions include biological control, chemical control, decontamination, breeding for resistance as well as surveillance and awareness creation. There is need for efficient, cost-effective sampling and analytical methods that can be used for detection analysis of mycotoxins in developing countries.
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ABSTRACT: Smallholder farmers' perceptions and management practices of maize ear rots, and their implications in breeding for host plant resistance were investigated using a participatory rural appraisal in four maize growing locations in central Zambia: Barlastone, Kalimansenga, Kasaka and Mulabo. Focus group discussions and interviews were held with 90 randomly selected farmers on issues regarding major maize constraints, ear rots, associated mycotoxins, coping mechanisms, and existing cropping systems. Ear rots were identified as a serious disease of maize and ranked the third after maize streak virus and northern corn leaf blight. Of the ear rots, Fusarium ear rot caused by Fusarium verticillioides was most abundant. Too much rainfall and lack of disease-resistant varieties were perceived as the main important factors contributing to the high maize ear rot disease incidence. Less than 7% of the farmers were aware of the mycotoxins, ear rot fungi produce in the infected grain. The main methods of disease management included burning, throwing away, feeding to livestock and at times selling to illicit beer brewers of diseased maize ears and kernels. Though farmers (95%) predominantly grew hybrid maize, they displayed strong preferences for landraces due to their perceived superior disease resistance and other quality traits such as large grain size, taste and white flour. Therefore, it implies that breeding for resistance to ear rot should aim at developing cultivars that are not only ear rot resistant but also possess farmer's preferred traits.
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ABSTRACT: Exposure to environmental toxins is a 21st century global health problem that is often the result of dietary intake. Although efforts are made to reduce dietary toxin levels, they are often unsuccessful, warranting research into novel methods to reduce host exposure. Food-grade microbes that can be delivered to the gastrointestinal tract and that are capable of sequestering toxins present a safe and cost-effective intervention. We sought to investigate the potential for probiotic-supplemented yogurt to lower heavy metal levels in at-risk populations of pregnant women and in children in Mwanza, Tanzania, and to examine the microbiome in relation to toxin levels. Two populations suspected to have high toxic metal exposures were studied. A group of 44 school-aged children was followed over 25 days, and 60 pregnant women were followed over their last two trimesters until birth. A yogurt containing 10(10) CFU Lactobacillus rhamnosus GR-1 per 250 g was administered, while control groups received either whole milk or no intervention. Changes in blood metal levels were assessed, and the gut microbiomes of the children were profiled by analyzing 16S rRNA sequencing via the Ion Torrent platform. The children and pregnant women in the study were found to have elevated blood levels of lead and mercury compared to age- and sex-matched Canadians. Consumption of probiotic yogurt had a protective effect against further increases in mercury (3.2 nmol/liter; P = 0.035) and arsenic (2.3 nmol/liter; P = 0.011) blood levels in the pregnant women, but this trend was not statistically significant in the children. Elevated blood lead was associated with increases in Succinivibrionaceae and Gammaproteobacteria relative abundance levels in stool.mBio 08/2014; 5(5). · 6.88 Impact Factor
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ABSTRACT: Aflatoxins and heavy metals were investigated in some poultry feed samples used as starter, grower, developer, layer, rabbit feed and bran which obtained from the local market at Al-Qassim region, Saudi Arabia. The results indicated that different amounts of aflatoxins were found in the analyzed samples. They reached peak values of 70.6, 46.38 and 50.88 µg/kg sample for aflatoxin B1, G1, and G2, respectively, however aflatoxin B2 was generally less than 2.0 µg/kg. The study showed that the levels of aflatoxins were generally below the permissible levels (100 -200 µg/kg). The results, also indicated that different levels of lead, cadmium, chromium, cobalt, nickel, zinc, manganese, iron and copper were detected in all samples. They ranged from 0. mg/kg for lead, cadmium, cobalt, zinc, manganese, iron, copper, chromium and nickel, respectively. The high levels of zinc, copper, manganese and iron may reflecting the deliberate addition of these metals to meet animal nutrient requirements. Cadmium levels were less than the permissible limit of 0.5 mg/kg in US feeds. Lead levels in most feed sample exceeded the permissible limit of < 1 mg/ kg in UK. However, they lower than the allowed lead content in feed ingredients according to the current official regulations (10 mg/ kg).01/2010; 4693382018:192-19977.