Strains of the Bacillus subtilis group produce extracellular hydrolytic enzymes, potent antifungal lipopeptides, and extracellular polymeric compounds. Toxins are produced by these organisms such as nonhemolytic enterotoxin ( nhe), hemolysin BL ( hbl), cytotoxin K ( cytK), cereulide, and the Conclusionsīacillus species are an underappreciated group of bacteria that are prevalent in numerous food fermentations, particularly in Asia, South America and Africa. mycoides, which includes strains previously designated as B. Toxins are produced by certain strains of the B. The bacterial microbiota composition of daqu is diverse and includes Bacillus spp., Enterobacteriaceae, and Assessment of the safety of Bacillus species and their toxinsīacillus species are also of concern for food safety. The liquor starter is prepared with different grains, including wheat, rice, and sorghum, that are shaped in blocks and fermented with controlled temperature and humidity. Cassava also contains the cyanogenic glycosides linamarin and lotaustralin that release Daquĭaqu is a spontaneous solid-state cereal fermentation that is used as a saccharification starter to initiate the alcoholic mash fermentation for production of cereal liquors and vinegars in China (Figure 3) 41, 42. In most African and Asian countries, the traditional diets of a majority of people rely largely on cassava and yam, which are poor in other nutrients, particularly proteins, essential amino acids, vitamins, and minerals, but contain significant amounts of starch and dietary fiber. Tubers, including cassava, yams, and potatoes, are second only to cereals in importance as a global source of carbohydrates. Roots, tubers, and vanilla fermentation products Several examples are presented in more detail below. frequently occur in alkaline food fermentations, which use soybeans as substrate. Moreover, the overview in Table 1 does not reflect that fermented foods are produced in numerous Fermented products from soybean and pulsesĬonsumption of soybean and soybean-derived fermented products has a long history in many East and South Asian countries (Table 1). The overview is likely incomplete because not all fermented foods are documented in the scientific literature. Major processing and fermentation steps are also indicated in Table 1 to inform on major processing steps and fermentation conditions that select for Bacillus species. Section snippets The presence of Bacillus in food fermentationsĪn overview on food fermentations that include Bacillus species as major fermentation organisms is shown in Table 1. This review aims to provide an overview on the role of Bacillus in food fermentations by presenting traditional fermented foods that include Bacillus species as major fermentation organisms, their specific contribution to food quality and safety, and explore the potential of using these organisms in nonconventional fermentation processes. Because spores survive even cooking steps, cooked or uncooked cereal grains, pulses and cassava generally harbor endospores of Bacillus species 15, 16.īacillus species are recruited for traditional food fermentations of pulses, tubers, or cereals in Asia, Africa, and South America (Figure 2) 3, 17, 18 The presence of Bacillus spores in plants, including cereals, pulses, and cassava relates to their occurrence as endophytes 10, 11, 12, 13. and their relevance for plant agriculture and food production is shown in Figure 1. The resistance of spores to high temperature and high pressure and thus the survival in ingredients that are cooked or steamed is further increased by the spoVA 2mob operon 8 Bacillus endospores resist adverse conditions, including heat, pressure, desiccation, and chemical assaults 6, 7. They form endospores as a key element of their ecology. are isolated from soil, water, and plants, and are almost ubiquitously present in foods. The contribution of Bacillus to food quality is not nearly as well documented as the contribution of yeasts and lactobacilli.īacillus spp. Most fermentations include yeasts and/or lactic acid bacteria (LAB) as major fermentation microbes, but mycelial molds, acetic acid bacteria, staphylococci, propionibacteria, Enterobacteriaceae, and bacilli also play dominant roles in some fermented foods. The assembly of communities of fermentation microbes is determined by the fermentation conditions, that is, the ingredients, temperature, pH, moisture content, and using backslopping or starter cultures. In addition, the presence of live microorganisms in fermented foods is increasingly recognized to improve gastrointestinal health 1, 2 Food fermentations utilize the activity of microorganisms for conversion of food components to improve shelf life and safety, as well as sensory and nutritional properties of food.
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