F01007: Literature review of the safety and suitability of Bacillus species for use as probiotics in animal nutrition

Study Duration: February 2002 to March 2003

Contractor: London Metropolitan University

There has been some concern over possible consequences for animal and human safety of Bacillus species in animal nutrition - such species are sometimes used in probiotic products to help boost feed efficiency. The Food Standards Agency sought to draw together information in order to help advise policy in this area.

The review was based on material from peer-reviewed journals, on-line databases, information and data from industry, and the Internet.

The data was incorporated into an ACCESS database and all information within the database was obtained from open sources.

Probiotic products (direct-fed microbials) are of increasing interest in animal production and in aquaculture and are also being introduced into supplements for domestic (companion) animals, most notably dogs. The most widely used micro-organisms are members of the lactic acid bacteria, especially species of Lactobacillus and Bifidobacterium. Other micro-organisms are used, including a number of members of the genus Bacillus (B. cereus, B. cereus var. toyoi, B. coagulans, B. clausii, B. licheniformis and B. subtilis) and a single species of Brevibacillus, namely Bv. laterosporus. Yeast cultures, usually Saccharomyces cerevisiae or Sacch. boulardii, are also used, especially in products for animal use.

Despite some established use as a probiotic micro-organism, there are concerns over the suitability of Bacillus species and related bacteria for use in animal feedingstuffs. These stem partly from the fact that, in contrast to the lactic acid bacteria and bifidobacteria, the Bacillus and Brevibacillus genera are not part of the normal intestinal microflora. The Bacillus species may include pathogens in addition to the extreme pathogen B. anthracis. Bacillus cereus.

Concerns remain, however, even for products that have received European Commission approval for marketing. These result from an increasing number of reports of Bacillus as a cause of human infections and findings of research suggesting a wider spectrum of pathogenic activity than previously recognised. There is also evidence that virulence genes are widely distributed across the Bacillaceae.

Although this report is primarily concerned with the use of the Bacillaceae in probiotic supplements for animal feeds, the same genera and, in some cases, the same strains are used in preparations for human consumption. Areas of concern with respect to safety and suitability are similar for food and feed use.

Under most circumstances, however, risk is significantly greater in human use, where the culture is ingested directly. It is also considered that any strain of Bacillus used as a probiotic should be fully characterised using molecular techniques and its relationship with other probiotic strains, including those considered unsuitable for use.

Project completed ' Final report is awaited.

Contact: For any enquiries concerning this research project, please contact the relevant Programme contact or email science@foodstandards.gsi.gov.uk