Abstract
Acute and subacute toxicity tests were undertaken on a novel galacto-oligosaccharide (GOS) produced from lactose by β-galactosidase derived from Bacillus circulans. Toxicity was evaluated by single dose oral administration (5,000 mg/kg) and was repeated at day 28 (1,000 mg/kg) in male and female Sprague-Dawley rats. In acute toxicity tests, the protein levels of male rats administered GOS showed a significant difference from controls, but remained within the normal range. There were no GOS-related changes in clinical symptoms, weight, food intake, hematology, blood chemistry, relative organ weight, or severe pathology in rats treated with GOS compared with controls. The no observed adverse effect level of GOS was at least 1,000 mg/kg/d in both male and female rats. Bovine-specific genes were not detected in GOS 70%-based products (NeoGOS-P70, NeoGOS-L70, and organic GOS), indirectly showing the absence of an allergen and that products containing GOS 70% are non-toxic and allergen-free.