Biocontrol of Aspergillus flavus Strains Isolated from Bambara Groundnut (Vigna subterranea (L.) Verdc.) Seeds Using Essential Oils of Lippia multiflora Moldenke, Ocimum americanum L. (Lamiaceae) and Eucalyptus cameldulensis Dehnh

In nature, plant extracts play a crucial role in defending plants against biotic and abiotic stressors. Moreover, the use of plant-based products, such as plant extracts, represents a promising alternative to synthetic fungicides, which pose potential health risks to consumers. In this study, the antifungal activity of the essential oils (EOs) of Lippia multiflora, Eucalyptus camaldulensis and Ocimum americanum was evaluated against two strains of Aspergillus flavus via the agar dilution method. These two Aspergillus flavus fungi was isolated from Bamabra groundnut seeds. Lippia multiflora essential oil (EO) showed the best results compared with the other oils, with a minimum inhibitory concentration (MIC) of 9000 μg∙mL−1. The MIC for Eucalyptus camaldulensis and Ocimum americanum EOs was 10,800 μg∙mL−1. In view of their antifungal properties, these EOs could be used to develop a new, safe antifungal agent for food preservation.

Assessment of Maize Contamination by Aflatoxin in Burkina Faso: A Review of Methods of Control

Aflatoxin contamination of crops is frequent in warm regions across the globe, including large areas in sub-Saharan Africa and Burkina Faso. A?atoxins and fumonisins are among the mycotoxins that have been increasingly reported to affect health and productivity of livestock globally. It cuts across the value chain, affecting farmers, markets, and finally consumers. However, a?atoxin contamination is a threatening issue in these staples and its negative effects on human health, most especially on infants and young children, are very alarming. Among the cereals in Burkina Faso, the maize is more vulnerable to contamination by Aspergillus sp. The contamination of maize by the aflatoxin is the main cause affecting production of agricultural sector, food security and regularity. Many factors are responsible for its proliferating. Therefore aflatoxins reduction in cereals such as maize is a serious concern for quality and safety. This review aimed to highlight the factors influencing a?atoxins contamination, and methods of reduction.

Purification Potential of Local Media in the Pre-Treatment of Greywater Using Vertical Biofilters under Sahelian Conditions

Several on-site greywater treatment systems are under development including biofiltration, whose efficiency is influenced by the filter media. Therefore, the main objective of this study was to evaluate the influence of the type of filter media and their grain size in the removal of organic and microbial pollutants from greywater. Hence, three types of local filter media of different grain size were used for the pre-treatment of greywater. Their removal potential and clogging time were evaluated and compared. The results indicated that the type of filter media and the grain size have an influence on the elimination of organic and microbial pollution from greywater. Indeed, sand of 1 - 2 mm in size obtained the highest removal efficiencies of organic pollutants (67.35% and 78.04% for COD and BOD5 respectively) and microbial indicators (2.07, 1.77 and 2.27 log. units for E. coli, fecal coliforms and enterococci respectively). Although media of fine texture enhanced the removal efficiencies, they experienced significant clogging problems. To overcome these limitations while enhancing the removal efficiency, 1) pre-treatment stage with coarse materials followed by a treatment with finer materials or 2) the use of a combination of fine and coarse materials should be considered.

Valorization of Agricultural Waste: Theoretical Estimation and Experimental Biomethane Yield from Cashew Nut Hulls

Biomethane potential production from cashew nut hulls, an agricultural waste, was carried out using old and fresh hulls as substrates. Samples were taken from old hulls (around 8 years old) and fresh hulls produced in cashew scale transformation units at Bobo Dioulasso/Burkina Faso. Physicochemical parameters showed that cashew hulls can be a good candidate for anaerobic digestion. But high acidity, total phenols and lignin tenor could be a constraint for anaerobic bacteria. Theoretical biochemical methane potential showed high value of 666.937 CH4 L. (Kg VS)-1 and 526.206 CH4 L. (Kg VS)-1 for crushed fresh and powdered old hulls, respectively. Experimental biochemical methane potential showed significantly low potential of 1.982 CH4 L. (Kg VM)-1 and 46.840 CH4 L. (Kg VM)-1 for fresh and hold hulls, respectively. Pretreatment for optimization, chemical composition and co-digestion system must be expected for a better anaerobic digestion performance.

Post-Harvest Fungi Associated with Cowpea (Vigna unguiculata L. Walp.) Seeds Produced in Burkina Faso

Cowpea is a very popular foodstuff among people in sub-Saharan Africa. In Burkina Faso, it is the main food legume, especially in rural areas. Its production is facing difficulties including post-harvest losses caused by fungi. Therefore, the objective of this study was to isolate and identify fungal strains associated with cowpea seeds produced in Burkina Faso. Thus, a total of 108 seed samples were collected in the three agro-ecological zones of Burkina Faso. The sanitary analysis of the seeds was carried out using the direct contact method. The isolation and purification of the isolates were performed on Potato Dextrose Agar medium while their identification was done through macroscopic and microscopic phenotypical characterization using different culture media (Potato Dextrose Agar (PDA), Malt Extract Agar (MEA) and Czapeck Dox Agar (CZA)) and different identification keys. A total of 10 fungal species were isolated, with predominance of Aspergillus flavus, Aspegillus niger, Macrophomina phaseolina, Fusarium oxysporium and Rhizopus sp. whose infection rates were 70.8% to 100% of seed samples. In addition to being present in all three zones, the infection rates of Aspergillus flavus (56.55%), Aspergillus niger (20.35%) and Rhizopus (32.80%) were higher in the Sahelian zone. In the Sudano-Sahelian zone, Macrophomina (50.66%) and Fusarium (18.88%) presented the highest infection rates, while Penicillium sp. showed the highest infection rate (2.84%) in the Sudanian zone. This finding demonstrated the necessity to improve post-harvest and conservation techniques of cowpea to limit crop losses and preserve the sanitary quality of this important foodstuff.

Assessment of Heavy Metals and Microbial Pollution of Lettuce (<i>Lactuca sativa</i>) Cultivated in Two Sites (Paspanga and Tanghin) of Ouagadougou, Burkina Faso

Environmental pollution can have detrimental effects on crop yield and its consumers. The current study was designed to investigate the potential human health risks associated with the consumption of lettuce crop contaminated with toxic heavy metals and microbiological status. Irrigated water, soil and lettuce were analyzed by AAS technics for heavy metals including Cd, Cr, Cu, Mn, Ni, Pb and Zn. Transfer factor (TF), daily intake of metals (DIM) and health risk index (HRI) were also calculated. Microbial analysis was carried out for the presence foodborne pathogens. The results showed that the heavy metals contents were higher in the soil than wastewater and the vegetables. Heavy metals ranged (mg·Kg-1) for Cd (1.27 to 2.93), Cr (7.28 to 7.38), Cu (0.91 to 1.70), Mn (0.29 to 6.60), Ni (1.74 to 2.16), Pb (1.32 to 1.69), Zn (3.08 to 3.79);and were higher than the WHO maximum limit permissible (ML) in vegetables. HRI TF values designated an enhanced bio-contamination. Microbial numeration revealed the presence of spoiler and pathogenic microorganisms. The lettuce tested was not safe for human use, especially for direct consumption by human beings.

Health Risk Assessment of Heavy Metals and Microbial Quality of Local Tomato (<i>Solanum lycopersicum</i>) of Ouagadougou, Burkina Faso

Tomato fruit enormously consumed in Burkina Faso is a source of health risk due to its quality. The plant of tomato cultivated in most the industrially polluted area as Ouagadougou, accumulates significant quantities of heavy metals and microorganisms and could be dangerous for consumption. The present study was conducted to investigate heavy metal and microbial contamination in soils wastewater and vegetables (tomato fruit) and to evaluate the possible health risks associated with the consumption of vegetables. Total concentrations of As, Cd, Cr, Cu, Hg, Ni, Se and Zn were determined using atomic absorption spectrophotometry. Transfer factor (TF), daily intake of metals (DIM) and health risk index (HRI) were also calculated. Microbial quality was analyzed for the presence of foodborne pathogens. The pH involved from 6.50 ± 0.1 to 9.40 ± 0.12 respectively for Boulmiougou and Kossodo. The mean metal concentrations indicated that soils were strongly polluted followed by wastewater and vegetable. The range of the mean values (in mg · kg-1) exhibited by As, Cd, Cr, Cu, Hg, Ni, Se and Zn in tomato fruit was 17.80 ± 0.32, 2.71 ± 0.02, 11.57 ± 0.2, 203.41 ± 1.20, 15.13 ± 0.30, 53.18 ± 0.20, 38.56 ± 0.10, 109.13 ± 0.25 concerning samples of Boulmiougou and 3.47 ± 0.15, 2.78 ± 0.01, 22.11 ± 0.1, 242.85 ± 2.10, 14.86 ± 0.10, 132.19 ± 1.50, 33.23 ± 0.15, 146.43 ± 1.12 for Kossodo. Microbial count was below to acceptable limits for vegetable, but underlined the presence of spoiler and foodborne pathogens. However, the daily intake of metals (DIM) and the health risk index (HRI) values were found to be under to the prescribed maximum tolerable.