Activity of 4CMB and 4HMB in bacterial mutation assays.

Conventional pour-plate tests were conducted using 5 Strains of S. typhimurium and 1 E. coli strain. The range of levels examined was 1.6-100 microgram per plate, for both chemicals. 4HMB was inactive in all tests. 4CMB was directly active in all strains, inducing both frameshift and base-substitution mutations in a dose-dependent manner. The largest responses were recorded in strains TA1538 and TA98.