An initial characterization of aflatoxin B1 contamination of maize sold in the principal retail markets of Kigali, Rwanda

Abstract

24Food security considerations have shifted in recent years, with the recognition that available food 25 should also be nutritious and safe. There is a growing evidence base for contamination of maize 26 and other crops by fungal toxins in the tropics and sub-tropics. As an initial snapshot of 27 contamination by one of these toxins in Rwanda, Aflatoxin B1 (AFB1) was analyzed in 684 28 samples of maize flour collected in seven principal retail markets of Kigali and in 21 samples of 29 animal feed from seven feed vendors. Two rounds of sample collections were carried out, the 30 first in September 2014 and the second in January 2015. A questionnaire given to vendors was 31 used to determine if gender and education level of vendors, origin of maize and awareness of 32 aflatoxins had any significant effect on AFB1 level in collected samples. Enzyme-Linked 33 Immunosorbent Assay (ELISA) and Immuno-affinity fluorimetery were used to analyze samples. 34 Only markets had a significant effect on AFB1 level; for the two collections, differences were 35 inconsistent among markets. In the first round, market means of AFB1 varied between 8.0+5.57 36 µg/kg and 24.7+23.74 µg/kg and for the second round, between 10.4+8.4 µg/kg and 25.7+25.85 37 µg/kg. In most animal feed samples AFB1 was >100 µg/kg. None of the vendors interviewed 38 was aware of the risk of mycotoxin contamination in their maize-based flours and feed. Limits 39 set by the United States Food and Drug Administration (20 µg/kg) for total aflatoxins and 40 European Commission (2 µg/kg) for AFB1 for maize flour imports, were varied between 2-35% 41 and 66-100% of samples, respectively. The implications of this study for human and animal 42 health in Rwanda suggest that expanded surveys are needed to understand the scope of 43 contamination, given the influence of environment and other factors on aflatoxin accumulation. 44 Available options to mitigate and monitor aflatoxin contamination can be further deployed to 45 reduce contamination.46 47

Near Infrared Spectrometry for Rapid Non-Invasive Modelling of Aspergillus-Contaminated Maturing Kernels of Maize (Zea mays L.)

“…Rapid and early detection is important for prompt intervention. Current detection methods include high-performance liquid chromatography (HPLC), Enzyme Linked Immunosorbent Assay ELISA, fluorometric assays and lateral flow assays [16][17][18][19]. However, these methods are invasive, require specialised skills and are weak for real time assessments.…”

Inadequacy of nutrients and contaminants found in porridge‐type complementary foods in Rwanda

“…The present study showed that mycotoxin and microbiological contamination, as well as the presence of pesticides, represent an unacceptable risk for this vulnerable population. The problem of high aflatoxin levels lies not only in the fungal‐promoting weather conditions of Africa (Clay & Dejaegher, ) but also in the lack of awareness of mycotoxin contamination risks (Nishimwe, Wanjuki, Karangwa, Darnell, & Harvey, ).…”

“…The high susceptibility of maize products to aflatoxins in our study is consistent with existing literature and highlights the need for deliberate action to ensure food safety in infant products. Two previous studies provided information on mycotoxin levels in products available in the Kigali market (Matsiko et al, ; Nishimwe et al, ). More than 680 maize flours were analysed in the study of Nishimwe et al (), showing total aflatoxin levels generally above tolerable limits set by the European Commission (4 μg/kg; European Commission, ), the Kenyan Government, and the United Nations World Food Programme (10 μg/kg; International Food Programme Research Institute, ) and the U.S. Food and Drug Administration (20 μg/kg; U.S. Food and Drug Administration, ) for maize products.…”

Evaluation of mycotoxin content in soybean (Glycine max L.) grown in Rwanda

“…More than 90% (92.7%) of the respondents did not know the term "aflatoxin" and were not aware of the problem of toxins, even not in their local language Kinyarwanda. These findings clearly have shown that there is a need to create awareness on AF among the Rwandese by training to prevent food colonization by mycotoxigenic fungi [36]. Ignorance on the understanding of AF, and conditions in which producing fungal species grow, could lead to acute and chronic toxicity [37], and subsequent AF outbreaks [13,38].…”

“…Aflatoxin contamination of maize can be a problem, similar to reports from other countries in the region. Maize in principal retail markets in Rwanda was found to be contaminated by aflatoxin (2-35% and 66-100% of samples were above the US and EU limits, respectively) with AF up to 26 µg/kg [36]. A three-year survey done on soybean in America, Europe, Asia and Oceania on the mycotoxins occurrence in feed proved that soybean was mostly contaminated by FB (range, 12 µg/kg -2,966 µg/kg) [58].…”