Lack of genotoxicity and subchronic toxicity in safety assessment studies of formulation.

A powder formulation of viable bacteria (AMUC) was evaluated in a 90-day repeated-dose toxicity study in rats and a battery of genotoxicity studies to evaluate AMUC as a food ingredient. All studies followed Organisation for Economic Co-operation and Development protocols (OECD TG 408, 471 473, 474). AMUC was administered to rats gavage at 0, 500, 1000, and 2000 mg/kg body weight/day (equivalent to 0, 4.1 × 10, 9.2 × 10, and 1.64 × 10 CFU/kg body weight/day). No mortality or treatment-related adverse effects were reported in any endpoints that were attributed to AMUC consumption. No bacterial translocation of viable from the intestinal tract was found to the liver, mesenteric lymph nodes, or blood. The no-observed-adverse-effect level was concluded to be the highest dose tested (2000 mg/kg body weight/day), approximately 1.64 × 10 CFU/kg body weight/day. AMUC (nonviable) was not mutagenic when examined in an bacterial reverse mutation assay and not clastogenic in an mammalian chromosomal aberration test. Viable AMUC was not genotoxic when evaluated in an mammalian cell micronucleus assay when administered at up to 1.64 ×10 CFU/kg body weight/day. These results confirm that AMUC is not toxic under the conditions of these studies.