Mutagenic evaluation of single cell protein with various mammalian test systems.

Single cell protein (SCP)--a product containing 80% raw protein obtained from bacteria grown on a methanol substrate--was tested for mutagenicity in 5 in vivo tests in different mammalian species. The animals were fed either a standard laboratory diet, a semi-synthetic diet, diets containing 12.5 and 25% SCP or pure SCP. The following investigations were carried out: dominant-lethal-test; host-mediated assay; micronucleus test; chromosome studies in bone marrow cells; in vivo sister chromatid exchange test. The statistical evaluation of all test results did not reveal any evidence for mutagenic activity of the SCP.