This study characterized the health risks due to the consumption of mycotoxin-contaminated foods and assessed the consumer awareness level of mycotoxins in households in two north-central Nigerian states during the harvest and storage seasons of 2018. Twenty-six mycotoxins and 121 other microbial and plant metabolites were quantified by LC-MS/MS in 250 samples of cereals, nuts and legumes. Aflatoxins were detected in all food types (cowpea, maize, peanut and sorghum) except in millet. Aflatoxin B₁ was the most prevalent mycotoxin in peanut (64%) and rice (57%), while fumonisin B₁ occurred most in maize (93%) and beauvericin in sorghum (71%). The total aflatoxin concentration was highest in peanut (max: 8422 µg/kg; mean: 1281 µg/kg) and rice (max: 955 µg/kg; mean: 94 µg/kg), whereas the totals of the B-type fumonisins and citrinin were highest in maize (max: 68,204 µg/kg; mean: 2988 µg/kg) and sorghum (max: 1335 µg/kg; mean: 186 µg/kg), respectively. Citrinin levels also reached 51,195 µg/kg (mean: 2343 µg/kg) in maize. Aflatoxin and citrinin concentrations in maize were significantly (p < 0.05) higher during storage than at harvest. The estimated chronic exposures to aflatoxins, citrinin and fumonisins were high, resulting in as much as 247 new liver cancer cases/year/100,000 population and risks of nephrotoxicity and esophageal cancer, respectively. Children who consumed the foods were the most vulnerable. Mycotoxin co-occurrence was evident, which could increase the health risk of the outcomes. Awareness of mycotoxin issues was generally low among the households.

Kunu is a traditional fermented single or mixed cereals-based beverage popularly consumed in many parts of West Africa. Presently, the bacterial community and mycotoxin contamination profiles during processing of various kunu formulations have never been comprehensively studied. This study, therefore, investigated the bacterial community and multi-mycotoxin dynamics during the processing of three kunu formulations using high-throughput sequence analysis of partial 16S rRNA gene (hypervariable V3-V4 region) and liquid chromatography tandem mass spectrometry (LC-MS/MS), respectively. A total of 2,303 operational taxonomic units (OTUs) were obtained across six processing stages in all three kunu formulations. Principal coordinate analysis biplots of the Bray-Curtis dissimilarity between bacterial communities revealed the combined influences of formulations and processing steps. Taxonomically, OTUs spanned 13 phyla and 486 genera. Firmicutes (phylum) dominated (relative abundance) most of the processing stages, while Proteobacteria dominated the rest of the stages. Lactobacillus (genus taxa level) dominated most processing stages and the final product (kunu) of two formulations, whereas Clostridium sensu stricto (cluster 1) dominated kunu of one formulation, constituting a novel observation. We further identified Acetobacter, Propionibacterium, Gluconacetobacter, and Gluconobacter previously not associated with kunu processing. Shared phylotypes between all communities were dominated by lactic acid bacteria including species of Lactobacillus, Lactococcus, Leuconostoc, Pediococcus, and Weissella. Other shared phylotypes included notable acetic acid bacteria and potential human enteric pathogens. Ten mycotoxins [3-Nitropropionic acid, aflatoxicol, aflatoxin B₁ (AFB₁), AFB₂, AFM₁, alternariol (AOH), alternariolmethylether (AME), beauvericin (BEAU), citrinin, and moniliformin] were quantified at varying concentrations in ingredients for kunu processing. Except for AOH, AME, and BEAU that were retained at minimal levels of < 2 μg/kg in the final product, most mycotoxins in the ingredients were not detectable after processing. In particular, mycotoxin levels were substantially reduced by fermentation, although simple dilution and sieving also contributed to mycotoxin reduction. This study reinforces the perception of kunu as a rich source of bacteria with beneficial attributes to consumer health, and provides in-depth understanding of the microbiology of kunu processing, as well as information on mycotoxin contamination and reduction during this process. These findings may aid the development of starter culture technology for safe and quality kunu production.

Mycological investigation of various foods (mainly cowpea, groundnut, maize, rice, sorghum) and agricultural soils from two states in north-central Nigeria (Nasarawa and Niger), was conducted in order to understand the role of filamentous fungi in food contamination and public health. A total of 839 fungal isolates were recovered from 84% of the 250 food and all 30 soil samples. Preliminary identifications were made, based on macro- and micromorphological characters. Representative strains (n = 121) were studied in detail using morphology and DNA sequencing, involving genera/species-specific markers, while extrolite profiles using LC-MS/MS were obtained for a selection of strains. The representative strains grouped in seven genera (Aspergillus,Fusarium,Macrophomina,Meyerozyma,Neocosmospora,NeotestudinaandPhoma). Amongst the 21 species that were isolated during this study was one novel species belonging to theFusarium fujikuroispecies complex,F. madaensesp. nov., obtained from groundnut and sorghum in Nasarawa state. The examined strains produced diverse extrolites, including several uncommon compounds: averantinmethylether inA. aflatoxiformans; aspergillimide inA. flavus; heptelidic acid inA. austwickii; desoxypaxillin, kotanin A and paspalitrems (A and B) inA. aflatoxiformans,A. austwickiiandA. cerealis; aurasperon C, dimethylsulochrin, fellutanine A, methylorsellinic acid, nigragillin and pyrophen inA. brunneoviolaceus; cyclosporins (A, B, C and H) inA. niger; methylorsellinic acid, pyrophen and secalonic acid inA. piperis; aspulvinone E, fonsecin, kojic acid, kotanin A, malformin C, pyranonigrin and pyrophen inA. vadensis; and all compounds inF. madaensesp. nov.,Meyerozyma,NeocosmosporaandNeotestudina. This study provides snapshot data for prediction of food contamination and fungal biodiversity exploitation.

The biosynthesis of nanoparticles using environmentally friendly routes has gained attention due to the need for safe, non-toxic, and cost-effective methods of nanomaterials synthesis. In the present study, different volumes (10, 20, and 30 mL) of aqueous leaf extract of Globularia alypum (GA) were used to synthesize titanium dioxide (TiO₂) nanoparticles (NPs). The synthesized NPs were characterized using multiple analytical techniques, including X-ray diffraction (XRD), ultraviolet–visible spectroscopy (UV–vis), transmission electron microscopy (TEM), and scanning electron microscopy (SEM). XRD results confirmed the rutile phase of TiO₂ as well as the crystalline nature and purity of the NPs. UV–Vis spectroscopy showed absorption spanning from the UV to the visible region, with a maximum peak between 325 and 370 nm. The calculated direct band gap energies were 3.40, 3.65, and 3.80 eV for TiO₂(3), TiO₂(2), and TiO₂(1), respectively. Both SEM and TEM indicated spherical nanoparticle morphology across all extract concentrations, with particle sizes increasing in direct proportion to the volume of extract used. Fourier Transform Infrared spectroscopy analysis of GA showed characteristic peaks for various functional groups that mediated the formation of the TiO₂ nanoparticles. The antibacterial properties of the biosynthesized TiO₂ NPs were evaluated against multiple clinically relevant Gram-positive and Gram-negative bacterial species. The TiO₂ nanoparticles demonstrated significant antimicrobial activity against all studied bacteria using the standard disc diffusion assay. At the least TiO₂ concentration of 10 µg/mL, highest anatimicrobial activity was observed against typed stains of Escherichia coli and Bacillus cereus, with inhibitory zone diameters of 17 mm and 16 mm, respectively. These results clearly indicate that plant-mediated nanoparticles could be useful for future biological applications, specifically in combating the challenge of drug resistance in clinical microorganisms.