Abstract
From the available literature, most of the data associated with the probiotics including Bacillus probiotics deal with their efficacy and potency rather than their safety and adverse effects. The majority of data about the safety of probiotics is also about Lactobacillus and Bifidobacterium, and minimum information is available about Bacillus probiotics. More studies are, therefore, required in relation to the safety of probiotics including Bacillus bacteria, it is well known that the safety assessment and data on a particular Bacillus probiotic strain cannot be generalized to a similar probiotic even with a different strain of the same species. This is because each Bacillus probiotic requires safety and risk assessment on a case-by-case basis. The antagonist effects and the harshness of the effects of a specific Bacillus probiotic could be a specific circumstance and depend on the immune-physiological status of the target host, for example, aquatic animals or human. Therefore, a Bacillus probiotic strain may be estimated to be safe under certain conditions but may not be safe in other conditions. It is noticeable to say that at the moment, no Bacillus probiotic can be considered 100% safe or with zero risk. Further, public understanding about the hazards from Bacillus probiotics is limited, and, therefore, there is an essential request for an appropriate hazard benefit analysis and statement of this to the consumer of the probiotics. Additionally, the contamination of Bacillus probiotics with harmful/unwanted micro-organisms or chemical substances is another important safety issue that requires a serious attention. This is because in some cases, the risks and hazards related to the contaminants can be a more vital issue than the specific quality of the probiotic. Therefore, the lack of assessment and systematic reporting about the safety aspects of probiotics including Bacillus species especially in aquaculture sector is a big gap and seriously warranted future research works. This present chapter addressed the so far reports on pathogenic Bacillus in fish and shellfish causing morbidity and mortality and discussed the safety aspects of Bacillus probiotics application in aquaculture industry.