Molecular identification and safety assessment of Bacillus strains isolated from Burkinabe traditional condiment “soumbala”

Abstract

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.

Characterization of Potential Virulence, Resistance to Antibiotics and Heavy Metals, and Biofilm-Forming Capabilities of Soil Lignocellulolytic Bacteria

“…No hemolytic properties were observed. The hemolytic activities of Bacillus [Dabiré et al, 2022], Chryseobacterium [Sud et al, 2020], Mycobacterium [Augenstreich et al, 2020], and Stenotrophomonas genera [Peters et al, 2020] were reported. However, only Bacillus sp.…”

Update of the list of qualified presumption of safety (QPS) recommended microbiological agents intentionally added to food or feed as notified to EFSA 17: suitability of taxonomic units notified to EFSA until September 2022

“…Of these seven papers, four did not deal with safety concerns related to QPS TUs. Three papers had problems related to the identification methodology used (Bae et al., 2022 ; Dabire et al., 2022 ; Yeak et al., 2022 ) and/or source attribution (Aly et al., 2022 ; Bae et al., 2022 ; Dorsch et al., 2022 ). The paper of Bae et al.…”

“…Bacteraemia was diagnosed in a highly immunocompromised patient suffering from gut dysbiosis with a B. subtillis strain also present in fermented soya (natto), which was consumed daily by the patient (Kato et al., 2022 ). Haemolytic activity was discovered in some B. amyloliquefaciens (Dabire et al., 2022 ; Gauri et al., 2022 ) and B. subtilis (Dabire et al., 2022 ) strains; a property which is covered by the qualification ‘absence of toxigenic activity’ for Bacillus spp.…”

“…Of these seven papers, four did not deal with safety concerns related to QPS TUs. Three papers had problems related to the identification methodology used Dabire et al, 2022; and/or source attribution (Aly et al, 2022;Dorsch et al, 2022). The paper of reported an endocarditis which could be due to infection by B. amyloliquefaciens; a link with the probiotic use of B. amyloliquefaciens spores was hypothesised although not experimentally confirmed.…”

Microbiological evaluation of the indigenous fermented condiment okpeye available at various retail markets in the south-eastern region of Nigeria

“…are reported to be the most important species involved in the fermentation of several indigenous African fermented condiments. These include soumbala , iru , daddawa and ogiri using raw materials such as locust beans and melon seeds [ [8] , [9] , [10] ]. The biochemical activities of Bacillus during fermentation are also responsible for the acceptable organoleptic characteristics such as taste, flavour, visual appearance, and texture [ 11 , 12 ] associated with these foods.…”