Prevalence of Aflatoxins in Wheat and Maize Grain Plant-Pest-Pathways at Three Zimbabwean Ports of Entries
Year: 2025
Type: article
Abstract: The presence of aflatoxin producing fungi in food imports necessitates rigorous screening. A total of 42 maize and wheat pest pathways found contaminated with aflatoxins-causing- fungi; (Aspergillus flavus and A. parasiticus) during 2023-2024 phytosanitary inspections at three Zimbabwe ports of entries were subjected to aflatoxin screening at the Fertilizers, Farm Feeds and Remedies Institute (FFRI) using semi-quantitative Best Food Method (BFD) by means of Thin Layer Chromatograph (TLC) to detect aflatoxins contamination. Standard reference mixes containing aflatoxins concentration of 0.5 μg/kg each for B1 and B2, and 0.25 μg/kg each for G1 and G2 were checks. Controls with known concentration of aflatoxins B1, B2, G1 and G2 were visibly seen under Ultra Violet (UV) light read at 365 nm and differences of spots intensity for B1 and B2 aflatoxins concentration of 12 μg/kg, 24 μg/kg and 36 μg/kg and G1 and G2 aflatoxins concentration 6 μg/kg, 12 μg/kg and 18 μg/kg were noted. However, despite the presence of aflatoxin causing fungi in the 42 samples tested, aflatoxins were not detected by the TLC which has a detection limit of <1ppb. Spearman’s rho correlation matrix showed perfectly (ρ = 1.000, p < 0.01) or near-perfectly correlation (ρ ≥ 0.999, p < 0.001) on the four aflatoxin groups (B1, B2, G1, G2). Perfect correlations were revealed between aflatoxins B1 and B2 and between aflatoxins G1 and G2 whilst extremely strong correlations were revealed between aflatoxins B1 and G1; B1 and G2; B2 and G1 and B2 and G2. The test was highly significant (p<0.001) suggesting strong indication of no association between the four aflatoxin categories. Chi-Square goodness of test revealed statistically significant deviations from the expected frequencies (χ² (4) = 154.083, p < 0.001) suggesting that observed distributions of the aflatoxin were not caused by random variation. Due to the risks of mycotoxin co-occurrences in cereals, the research recommends expanding the testing beyond aflatoxins to include fumonisins caused by Fusarium species and other mycotoxins associated with Penicillum sp and Macrophomina phaseolin as these pests were also isolated from the cross border cereal grain-pest-pathways entering Zimbabwe. This research was limited by non-testing of the isolated fungi on their potential to cause aflatoxins contamination.
Source: Science Discovery
Authors: Nhamo Mudada, Kudakwashe Nyaruwata, Louisa Makumbe, Dumisani Kutwyayo, Brian Shumba, Nyaradzo Nyatanga, Mutsa Chatyoka, Charity Kunaka, Nyamande Mapope, Wonder Ngezimana
Language: English
Subfield: Plant Science
Domain: Life Sciences
Open Access status: diamond
OpenAlex ID: W7114771363