Safety Assessment of Bacillus subtilis MB40 for Use in Foods and Dietary Supplements.

Jessica L Spears,Marisa O Rihner,Andrey I Nikiforov,Elizabeth A Lambert,Richard Kramer

doi:10.3390/nu13030733

Jessica L Spears, Marisa O Rihner + Show 3 more

Open Access

https://doi.org/10.3390/nu13030733

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Abstract

With the growing popularity of probiotics in dietary supplements, foods, and beverages, it is important to substantiate not only the health benefits and efficacy of unique strains but also safety. In the interest of consumer safety and product transparency, strain identification should include whole-genome sequencing and safety assessment should include genotypic and phenotypic studies. Bacillus subtilis MB40, a unique strain marketed for use in dietary supplements, and food and beverage, was assessed for safety and tolerability across in silico, in vitro, and in vivo studies. MB40 was assessed for the absence of undesirable genetic elements encoding toxins and mobile antibiotic resistance. Tolerability was assessed in both rats and healthy human volunteers. In silico and in vitro testing confirmed the absence of enterotoxin and mobile antibiotic resistance genes of safety concern to humans. In rats, the no-observed-adverse-effect level (NOAEL) for MB40 after repeated oral administration for 14 days was determined to be 2000 mg/kg bw/day (equivalent to 3.7 × 1011 CFU/kg bw/day). In a 28 day human tolerability trial, 10 × 109 CFU/day of MB40 was well tolerated. Based on genome sequencing, strain characterization, screening for undesirable attributes and evidence of safety by appropriately designed safety evaluation studies in rats and humans, Bacillus subtilis MB40 does not pose any human health concerns under the conditions tested.

Highlights

The effects of microorganisms on the human body have been studied for well over a century [1], research on microbes of the human gut has intensified over the past decade
Examples of substantiated health benefits of probiotics include the support of gastrointestinal health, immune health, and promotion of the growth of beneficial gut bacteria [3,4]
The potential of MB40 to produce toxins was evaluated in silico via nBLAST based on the presence of toxin-producing genes similar to those found in B. cereus and via BLASTx based on toxin proteins from B. cereus

Summary

Introduction

The effects of microorganisms on the human body have been studied for well over a century [1], research on microbes of the human gut has intensified over the past decade. Probiotics are live microorganisms that, when administered in adequate amounts, confer a health benefit on the host [2] This globally recognized definition sets a critical requirement that probiotics, such as specific strains of Lactobacillus spp., Bifidobacterium spp., and Bacillus spp., demonstrate a health benefit in a properly designed clinical study. Examples of substantiated health benefits of probiotics include the support of gastrointestinal health, immune health, and promotion of the growth of beneficial gut bacteria [3,4] Probiotics such as Bacillus coagulans and Bacillus subtilis have been clinically shown to improve dietary protein digestion [5] and help with occasional gas and bloating [6,7]. Despite the growing number of benefits associated with oral probiotic use, strain-specific safety is, first and foremost, a priority

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