The scientific interest in Bacillus species as probiotics though, has really grown only in the last 15 years and a number of important reviews cover this growing area of scientific interest. Of the species that have been most extensively examined these are Bacillus subtilis, Bacillus clausii, Bacillus cereus, Bacillus coagulans and Bacillus licheniformis.
Spores being heat-stable have a number of advantages over other non-spore-formers such as Lactobacillus spp., namely, that the product can be stored at room temperature in a desiccated form without any deleterious effect on viability. A second advantage is that the spore is capable of surviving the low pH of the gastric barrier which is not the case for all species of Lactobacillus so in principle a specified dose of spores can be stored indefinitely without refrigeration and the entire dose of ingested bacteria will reach the small intestine intact.
Spore probiotics are being used extensively in humans as dietary supplements, in animals as growth promoters and competitive exclusion agents and lastly in aquaculture for enhancing the growth and disease-resistance of cultured shrimps, most notably the Black Tiger shrimp (Penaeus monodon). Interestingly, a number of Bacillus products are licensed as medicinal supplements.
Professor Simon Cutting and therefore, SporeGen®, have extensive experience with Bacillus species as probiotics and have been involved in a number of GRAS applications, consultancies and contract work regarding the use of spores as probiotics and as animal feed supplements.