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 < 1 indicates minimal risk. 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.

In Burkina Faso, deficiency of amino acids in protein is becoming a major healthy public problem. This study was purposed to optimize essentials amino acids in single cell protein (SCP) by supplementing different nitrogen sources during fermentation of mango waste with Candida utilis FJM12. Analytical methods were used to determine biomass yield, chemical composition and amino acids profile of SCP. The principal component analysis (PCA) method was performed to identify the nitrogen source which exhibited best rate of SCP. The maximum biomass yield (6.48±0.03 g/L) exhibited 9.65±0.36% (w/w) of ash, while using yeast extract. The proximate composition of SCP revealed 56. 40±1.30, 13.25±0.11, 3.80±0.10 and 6.60±0.25% (w/w), respectively for crude protein, lipids, carbohydrates, and nucleic acid content. PCA showed a strong correlation between yeast extract and ammonium sulphate and demonstrated their positive influence to increase the rate of SCP and essentials amino acids as compared to Food and Agriculture Organization (FAO) recommendation. These results demonstrated that C. utilis FJM12 could be suitable for essentials amino acids.

Purpose Alkaline-fermented foods (AFFs) play an essential role in the diet of millions of Africans particularly in the fight against hidden hunger. Among AFFs, soumbala is a very popular condiment in Burkina Faso, available and affordable, rich in macronutrients (proteins, lipids, carbohydrates, essential amino acids, and fatty acids), micronutriments (minerals, B group vitamins), and fibers. Bacillus spp. are known to be the predominant microbial species in AFFs and thus have elicited enhanced interest as starter cultures or probiotics. However, few data exist on identification and safety attributes of relevant Bacillus species from African AFFs, particularly from Burkinabe soumbala. Methods This study aimed to genotypically characterize 20 Bacillus strains previously isolated from soumbala, using PCR and sequencing of the 16S rRNA genes, and to evaluate their safety attributes. Results Phylogenetic analysis revealed that the strains were most closely related by decreasing numbers to B. cereus, B. subtilis, Bacillus sp., B. tropicus, B. toyonensis, B. nealsonii, B. amyloliquefaciens, Brevibacillus parabrevis, and B. altitudinis. Among the isolates, 10 were β-hemolytic and 6 were γ-hemolytic while 4 were of indeterminate hemolysis. The 6 γ-hemolytic (presumptively non-pathogenic) strains were susceptible to all tested antibiotics except bacitracin. Strains F20, and F21 were the most sensitive to imipenem (38.04 ± 1.73 mm and 38.80 ± 1.57 mm, respectively) while strain B54 showed the weakest sensitivity to bacitracin (11.00 ± 0.63 mm) with high significant differences (p < 0.0001). Conclusion The findings highlight identification and safety quality of Bacillus strains which could be further characterized as probiotic-starter cultures for high-quality soumbala production.

Background Soumbala is a highly loved alkaline traditional fermented food condiment in Burkina Faso. It harbors various microbiota dominated by fermentative Bacillus spp. as functional microorganism with little confirmed health-promoting properties. Methods The present study aimed to evaluate six Bacillus strains previously isolated and identified from soumbala. These strains were selected as presumptively safe bacteria for probiotic and technological characteristics. These strains were assessed for in vitro probiotic criteria (tolerance to acidic pH, gastric juice, 0.3% (m/v) bile salts, intestinal juice and 0.4% (w/v) phenol, cell surface hydrophobicity, auto-aggregation capacity, antimicrobial activity against foodborne pathogens, antibiotic susceptibility and biofilm production) and technological properties, including protease, amylase, lipase, and tannase activity, as well as poly-γ-glutamic acid (PGA) production and thermo-tolerance. Results All tested Bacillus strains (B54, F20, F24, F21, F26 and F44) presented variable relevant probiotic properties (good tolerance to pH 2 and pH 4, gastric juice, bile salts, intestinal juice and phenol), with marked differences in hydrophobicity and auto-aggregation capacity ranging from 73.62—94.71% and 49.35—92.30%, respectively. They exhibited a broad spectrum of activity against foodborne pathogens depending on target pathogen, with the highest activity exhibited by strain F20 (29.52 mm) against B. cereus 39 (p <  0.001). They also showed good biofilm production as well as variable hydrolytic enzyme activities, including protease (43.00—60.67 mm), amylase (22.59—49.55 mm), lipase (20.02—24.57 mm), and tannase (0—10.67 mm). All tested Bacillus strains tolerated temperature up to 50 °C, while only strains F26 and F44 showed the best PGA production. Conclusion Overall, the tested cultures exhibiting potential probiotic and technological characteristics; particularly B. cereus F20, B. benzoevorans F21, B. cabrialessi F26, and B. tequilensis F44 could be a source of probiotic-starters of commercial interest in the production of high-quality soumbala.

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.