Diversity of bacillus species isolated from okpehe, a traditional fermented soup condiment from Nigeria

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

In Africa, indigenous fermented condiments contribute to food security as a low-cost source of protein. Okpeye is an indigenous fermented condiment produced from Prosopis africana seeds. The reliance on spontaneous fermentation processes and unhygienic practices during production often results in the contamination of the final product with microbial hazards. A microbiological evaluation of 18 commercial samples of okpeye purchased from six markets in two cities in southeastern Nigeria was conducted. Fifty-nine (59) bacteria were isolated and identified at the species level by phenotyping and sequencing the 16S rRNA, gyrB and rpoB genes. Bacillus (47.4 %) and Staphylococcus (42.3 %) were the predominant bacterial genera in okpeye. Overall, B. amyloliquefaciens and S. simulans were the most frequently occurring bacteria and were present in all samples. In addition, B. cereus was isolated in samples obtained from all markets. Other bacterial species included B. velezensis, Oceanobacillus caeni, S. cohnii, Escherichia fergusonni and Vagacoccus lutrae. The B. cereus isolates (10) were screened for the presence of 8 enterotoxin genes (hblA, hblC, hblD, nheA, nheB, nheC, cytK, entFM) and one emetic gene (cesB). The non-haemolytic enterotoxin (nheABC) and haemolytic enterotoxin (hblABD) complexes were present in 70 % and 50 % of B. cereus respectively. The positive rate of cytK and entFM genes was 70 %, while the cesB gene was 30 %. Antibiotic susceptibility assessment showed that most of the isolates were susceptible to gentamicin, tetracycline, streptomycin, and erythromycin but resistant to ciprofloxacin and vancomycin. These findings highlight the need for further controls to reduce contamination with potential pathogenic bacteria in indigenous fermented condiments such as okpeye. There is also a need to educate producers regarding hygienic practices to safeguard public health and food security.

Plant-Based Alkaline Fermented Foods as Sustainable Sources of Nutrients and Health-Promoting Bioactive Compounds

Traditional food fermentation is a practice that precedes human history. Acidic products such as yogurts and sourdoughs or alcoholic beverages produced through lactic acid or yeast fermentations, respectively, are widely described and documented. However, a relatively less popular group of fermented products known as alkaline fermented foods are common traditional products in Africa and Asia. These products are so called “alkaline” because the pH tends to increase during fermentation due to the formation of ammonia resulting from protein degradation by Bacillus species. Plant-based alkaline fermented foods (AFFs) are generally produced from legumes including soybean, non-soybean leguminous seeds, and other non-legume plant raw materials. Alkaline fermented food products such as natto, douchi, kinema, doenjang, chongkukjang, thua nao, meitauza, yandou, dawadawa/iru, ugba, kawal, okpehe, otiru, oso, ogiri, bikalga, maari/tayohounta, ntoba mbodi, cabuk, and owoh are produced at small industrial scale or household levels and widely consumed in Asia and Africa where they provide essential nutrients and health-promoting bioactive compounds for the population. Alkaline food fermentation is important for sustainable food security as it contributes to traditional dietary diversity, significantly reduces antinutritional components in raw plant materials thereby improving digestibility, improves health via the production of vitamins, and may confer probiotic and post-biotic effects onto consumers. In this review, we present currently available scientific information on plant-based AFFs and their role as sustainable sources of nutrients and bioactive compounds for improved health. Finally, we provide perspectives on research needs required to harness the full potential of AFFs in contributing to nutrition and health.

Safety Evaluation and In vivo Strain-Specific Functionality of Bacillus Strains Isolated from Korean Traditional Fermented Foods

Unveiling and understanding differences in physiological features below the species level may serve as an essential fast-screening tool for selecting strains that can promote a specific probiotic effect. To study the intra-species diversity of Bacillus, a genus with a wide range of enzyme activities and specificity, 190 Bacillus strains were isolated from traditional Korean fermented food products. Altogether, in the preliminary safety screening, 8 of these strains were found negative for lecithinase and hemolysis activity and were selected for further investigations. On the basis of different levels of enzyme functionalities (high or low proteolytic, amylolytic, and lipolytic (PAL) activities), two Bacillus subtilis strains were selected for an in vivo study. Each of the two strains was separately administered at a level of 1 × 10⁸ CFU per day to C57BL/6 mice that were fed 60% high-fat diet ad libitum for 8 weeks, while Xenical, an anti-obesity drug, was used as a positive control in the experimental setup. B. subtilis M34 and B. subtilis GS40a with low and high amylolytic activities, respectively, induced significantly different and contrasting physiological effects. The production of short-chain fatty acids appeared to be closely associated with a shift in the gut microbiota.

Technologically relevant Bacillus species and microbial safety of West African traditional alkaline fermented seed condiments

Fermented food condiments serve as a major source of nutrients to many homes in West Africa, especially among the rural poor who use these condiments as a cheap source of protein substitute for milk and other animal protein sources. Traditional fermented West African condiments are produced by spontaneous fermentation of legumes and protein-rich seeds of both cultivated and wild plant species. These fermented condiments are culturally accepted and widely produced in the West African sub-region, and rely on indigenous microbiota responsible for taste, texture, aroma development and the overall unique product characteristics. Detailed understanding of fermentation microbiota and their unique technological and functional properties are fundamental in developing products with enhanced quality and safety, as well as development of specific locally adapted starter cultures. Technologically relevant Bacillus spp., mainly Bacillus subtilis, are the predominant fermentative bacteria responsible for the natural fermentation of condiments across West Africa. Other species of Bacillus including B. amyloliquefaciens, B. licheniformis, B. pumilus, B. megaterium, B. sphaericus, B. cereus, B. badius and B. fusiformis are also frequently involved in the fermentation process. These bacterial species are responsible for flavor development, bio-conversion of complex food molecules, and production of antimicrobial compounds that impact shelf-life and safety, and in some instances, may confer host-beneficial health effects beyond basic nutrition. First, this review provides currently available information on the technologically relevant Bacillus species isolated from fermented food condiments in nine (9) West African countries. In addition, perspectives on harnessing the potentials of the technologically beneficial bacterial strains in fermented condiments in West Africa for enhanced food safety, quality and overall food security is presented.

Trends in the application of Bacillus in fermented foods

Bacillus species such as Bacillus subtilis and Bacillus amyloliquefaciens are widely used to produce fermented foods from soybeans and locust beans in Asian and West African countries, respectively. Genomic information for B. subtilis strains isolated from Asian Bacillus-fermented foods (BFFs) has been gathered, and the chemical components of fermented products were defined with metabolomic approaches, facilitating the development of new starter strains and the evaluation of health claims. On the other hand, although advanced studies have been performed for some commercially produced BFFs, home-manufactured products still remain to be characterized in rural areas. In West Africa, the microbial flora of BFFs was examined in detail, leading to the isolation of candidates of the starter that produced bacteriocin against Bacillus cereus contaminating the products. These studies may provide a choice of Bacillus strains in food application and increase opportunities for further usage of Bacillus in foods.

The Biotechnology of Ugba, a Nigerian Traditional Fermented Food Condiment

Legumes and oil bean seeds used for the production of condiments in Africa are inedible in their natural state; they contain some anti-nutritional factors especially undigestible oligosaccharides and phytate. Fermentation impact desirable changes by reducing anti-nutritional factors and increasing digestibility. Ugba is an alkaline fermented African oil bean cotyledon (Pentaclethra macrophylla) produced by the Ibos and other ethnic groups in southern Nigeria. Seen as a family business in many homes, its preparation is in accordance with handed-down tradition from previous generations and serves as a cheap source of plant protein. Its consumption as a native salad is made possible by fermentation of the cotyledon for 2–5 days, but could also serve as a soup flavoring agent when fermentation last for 6–10 days. The fermentation process involved is usually natural with an attendant issue of product safety, quality and inconsistency. The production of this condiment is on a small scale and the equipment used are very rudimentary, devoid of good manufacturing procedures that call to question the issue of microbial safety. This paper therefore reviews the production process and the spectrum of microbial composition involved during fermentation. In addition, potential spoilage agents, nutritional and biochemical changes during production are examined. Furthermore, information that can support development of starter cultures for controlled fermentation process in order to guarantee microbiological safety, quality and improved shelf life are also discussed.

Produce from Africa's Gardens: Potential for Leafy Vegetable and Fruit Fermentations

A rich variety of indigenous fruits and vegetables grow in Africa, which contribute to the nutrition and health of Africa's populations. Fruits and vegetables have high moisture and are thus inherently prone to accelerated spoilage. Food fermentation still plays a major role in combating food spoilage and foodborne diseases that are prevalent in many of Africa's resource disadvantaged regions. Lactic acid fermentation is probably the oldest and best-accepted food processing method among the African people, and is largely a home-based process. Fermentation of leafy vegetables and fruits is, however, underutilized in Africa, although such fermented products could contribute toward improving nutrition and food security in this continent, where many are still malnourished and suffer from hidden hunger. Fermentation of leafy vegetables and fruits may not only improve safety and prolong shelf life, but may also enhance the availability of some trace minerals, vitamins and anti-oxidants. Cassava, cow-peas, amaranth, African nightshade, and spider plant leaves have a potential for fermentation, as do various fruits for the production of vinegars or fruit beers and wines. What is needed to accelerate efforts for production of fermented leaves and vegetables is the development of fermentation protocols, training of personnel and scale-up of production methods. Furthermore, suitable starter cultures need to be developed and produced to guarantee the success of the fermentations.

Review: Diversity of Microorganisms in Global Fermented Foods and Beverages

Culturalable and non-culturable microorganisms naturally ferment majority of global fermented foods and beverages. Traditional food fermentation represents an extremely valuable cultural heritage in most regions, and harbors a huge genetic potential of valuable but hitherto undiscovered strains. Holistic approaches for identification and complete profiling of both culturalable and non-culturable microorganisms in global fermented foods are of interest to food microbiologists. The application of culture-independent technique has thrown new light on the diversity of a number of hitherto unknown and non-cultural microorganisms in naturally fermented foods. Functional bacterial groups ("phylotypes") may be reflected by their mRNA expression in a particular substrate and not by mere DNA-level detection. An attempt has been made to review the microbiology of some fermented foods and alcoholic beverages of the world.

Bacterial Diversity and Mycotoxin Reduction During Maize Fermentation (Steeping) for Ogi Production

Bacterial diversity and community structure of two maize varieties (white and yellow) during fermentation/steeping for ogi production, and the influence of spontaneous fermentation on mycotoxin reduction in the gruel were studied. A total of 142 bacterial isolates obtained at 24-96 h intervals were preliminarily identified by conventional microbiological methods while 60 selected isolates were clustered into 39 OTUs consisting of 15 species, 10 genera, and 3 phyla by 16S rRNA sequence analysis. Lactic acid bacteria constituted about 63% of all isolated bacteria and the genus Pediococcus dominated (white maize = 84.8%; yellow maize = 74.4%). Pediococcus acidilactici and Lactobacillus paraplantarum were found at all steeping intervals of white and yellow maize, respectively, while P. claussenii was present only at the climax stage of steeping white maize. In both maize varieties, P. pentosaceus was found at 24-72 h. Mycotoxin concentrations (μg/kg) in the unsteeped grains were: white maize (aflatoxin B1 = 0.60; citrinin = 85.8; cyclopiazonic acid = 23.5; fumonisins (B1/B2/B3) = 68.4-483; zearalenone = 3.3) and yellow maize (aflatoxins (B1/B2/M1) = 22.7-513; citrinin = 16,800; cyclopiazonic acid = 247; fumonisins (B1/B2/B3) = 252-1,586; zearalenone = 205). Mycotoxins in both maize varieties were significantly (p < 0.05) reduced across steeping periods. This study reports for the first time: (a) the association of L. paraplantarum, P. acidilactici, and P. claussenii with ogi production from maize, (b) citrinin occurrence in Nigerian maize and ogi, and

Combination of culture-independent and culture-dependent molecular methods for the determination of bacterial community of iru, a fermented Parkia biglobosa seeds

In this study, bacterial composition of iru produced by natural, uncontrolled fermentation of Parkia biglobosa seeds was assessed using culture-independent method in combination with culture-based genotypic typing techniques. PCR-denaturing gradient gel electrophoresis (DGGE) revealed similarity in DNA fragments with the two DNA extraction methods used and confirmed bacterial diversity in the 16 iru samples from different production regions. DNA sequencing of the highly variable V3 region of the 16S rRNA genes obtained from PCR-DGGE identified species related to Bacillus subtilis as consistent bacterial species in the fermented samples, while other major bands were identified as close relatives of Staphylococcus vitulinus, Morganella morganii, B. thuringiensis, S. saprophyticus, Tetragenococcus halophilus, Ureibacillus thermosphaericus, Brevibacillus parabrevis, Salinicoccus jeotgali, Brevibacterium sp. and uncultured bacteria clones. Bacillus species were cultured as potential starter cultures and clonal relationship of different isolates determined using amplified ribosomal DNA restriction analysis (ARDRA) combined with 16S-23S rRNA gene internal transcribed spacer (ITS) PCR amplification, restriction analysis (ITS-PCR-RFLP), and randomly amplified polymorphic DNA (RAPD-PCR). This further discriminated B. subtilis and its variants from food-borne pathogens such as B. cereus and suggested the need for development of controlled fermentation processes and good manufacturing practices (GMP) for iru production to achieve product consistency, safety quality, and improved shelf life.

Identification of surfactin producing strains in Soumbala and Bikalga fermented condiments using Polymerase Chain Reaction and Matrix Assisted Laser Desorption/Ionization-Mass Spectrometry methods

In this study, 67 strains were isolated from two fermented condiments from Burkina Faso: Soumbala and Bikalga. Phenotypical methods, biochemical tests and molecular approaches were used to determinate their genus or species. Twenty-two of them belong to the Bacillus genus. Six strains were selected for their antibacterial or antifungal properties. Their ability to produce lipopeptides synthesized by Non Ribosomal Peptide Synthetases was investigated using two different approaches: PCR with specific degenerated primers and Matrix-assisted Laser Desorption Ionization-Time of Flight Mass Spectrometry (MALDI-ToF MS) performed on whole cells cultivated on a solid medium. PCR revealed that the six strains contain genes involved in the biosynthesis of surfactins whereas surfactins C₁₄ and C₁₅ were only detected by MALDI-ToF MS in two of the six strains. For the first time, the presence of surfactins C₁₄ and C₁₅ was also identified by MALDI-ToF MS analyses directly performed on Soumbala methanolic crude extracts. The structure of these compounds was confirmed by +MS2 and +MS3 of sample and reference surfactins.

Distinct differentiation of closely related species of Bacillus subtilis group with industrial importance

PCR amplification of 16S rRNA gene by universal primers followed by restriction fragment length polymorphism analysis using RsaI, CfoI and HinfI endonucleases, distinctly differentiated closely related Bacillus amyloliquefaciens, Bacillus licheniformis and Bacillus pumilus from Bacillus subtilis sensu stricto. This simple, economical, rapid and reliable protocol could be an alternative to misleading phenotype-based grouping of these closely related species.

Diversity and applications of Bacillus bacteriocins

Members of the genus Bacillus are known to produce a wide arsenal of antimicrobial substances, including peptide and lipopeptide antibiotics, and bacteriocins. Many of the Bacillus bacteriocins belong to the lantibiotics, a category of post-translationally modified peptides widely disseminated among different bacterial clades. Lantibiotics are among the best-characterized antimicrobial peptides at the levels of peptide structure, genetic determinants and biosynthesis mechanisms. Members of the genus Bacillus also produce many other nonmodified bacteriocins, some of which resemble the pediocin-like bacteriocins of the lactic acid bacteria (LAB), while others show completely novel peptide sequences. Bacillus bacteriocins are increasingly becoming more important due to their sometimes broader spectra of inhibition (as compared with most LAB bacteriocins), which may include Gram-negative bacteria, yeasts or fungi, in addition to Gram-positive species, some of which are known to be pathogenic to humans and/or animals. The present review provides a general overview of Bacillus bacteriocins, including primary structure, biochemical and genetic characterization, classification and potential applications in food preservation as natural preservatives and in human and animal health as alternatives to conventional antibiotics. Furthermore, it addresses their environmental applications, such as bioprotection against the pre- and post-harvest decay of vegetables, or as plant growth promoters.