Lack of carcinogenicity of silicone resin (KS66) in F344 rats

The carcinogenic potential of silicone resin (KS66), used as an antifoaming food additive, was examined in both sexes of F344 rats. Groups of 50 female and 50 male animals were given diet containing KS66 at doses of 0%, 1.25% and 5.0%. No treatment related effects were noted regarding survival rate, general condition, body weight, food consumption, hematology and organ weight data. Detailed histopathological examination revealed no treatment-related increase in the incidences of any non-neoplastic or neoplastic lesions. The results demonstrate that KS66 is not carcinogenic in F344 rats of either sex.