Aflatoxin and Fumonisin Contamination of at-harvest and Storage Beans in Babati District, Northern Tanzania

Abstract

The natural occurrence of total aflatoxin and fumonisin was determined in 38 bean at-harvest samples and 106 storage beans samples in the year 2013 in Babati District Northern Tanzania. Quantification for total aflatoxin and fumonisin was done using Enzymes Linked Immunosorbent Assay -ELISA (Reveal AccuScan ® Neogen, USA), and the results were confirmed using Liquid Chromatography Tandem Mass Spectrometer (LC-MS/MS). Eighteen percent (7/38) of bean at harvest samples were contaminated with up to 3 µg/kg aflatoxins and no bean sample was contaminated with fumonisins. There was a significant correlation (p < 0.05) between the concentration of aflatoxins and fumonisins with climatic zones and agronomic practices. Only bean samples from the high altitude high rain zone were contaminated with aflatoxins (mean level of 1.53 µg/kg). For storage beans, samples from Seloto village were associated with higher aflatoxin concentration (mean of 3.74 µg/kg) and those from Long village were associated with higher fumonisin levels (mean of 9.0 mg/kg). These results indicate that beans consumers in the study area are exposed to the danger of chronic exposure to aflatoxin and fumonisin poisoning. Thus, those practices that reduce contamination should be adopted by all farmers in the study area to reduce the health hazards associated with consumption of contaminated beans. This also calls for further research to investigate human exposure to aflatoxin and fumonisin in the study area.

Occurrence of Fumonisins in Some Maize Meal Marketed to Consumers in Harare, Zimbabwe

“…This could be attributed to the cleaning method (screening and sifting), which did not completely eliminate fumonisins but only served to reduce them. Nyangi [7] reported that the most noticeable sign of Fusarium infection in maize grown in the tropical areas is kernel rot. However, fumonisins are often detected in maize kernels even if in the absence of invisible signs of infection.…”

“…These results are comparable to Pietri, et al [11], Brera, et al [22] and Vanara, et al [23] who reported that when the corn is milled, fumonisins are in elevated concentrations in the bran, followed by the germ fraction. Broggi and others carried out a study in a commercial dry-mill in Argentina and found a three-fold increase in fumonisin contamination in the germ and bran fractions than in the whole corn [7].…”

“…Insects, such as the maize stalk borer (Busseola fusca), infest maize cobs in the field and subsequently cause contamination of the grains by spreading mycotoxigenic fungi [7]. When water activity is high (aw> 0.9), fumonisins are synthesised in maize before harvesting [8].…”

Traditionally Processed Beverages in Africa: A Review of the Mycotoxin Occurrence Patterns and Exposure Assessment

“…According to Chilaka and others (), maize, and millet had higher FUM, DON, and ZEN contaminations than sorghum in Nigeria, most of which exceeded the maximum regulatory limit of 1000 μg/kg set for the sum of FB 1 and FB 2 by the EU (FAO ). Interestingly, pearl millet and finger millet, which are also used in preparing traditional beverages, especially in West and East Africa, were less susceptible to mycotoxin contamination as they had very low levels of AFB 1 (Chala and others ) and FUM (Nyangi ; Vismer and others ). It is thought that ZEN is the most common mycotoxin in both sorghum and finger millet (Chala and others ).…”