Copper nanoparticles (CuNPs) have antimicrobial properties, which have contributed to their widespread usesuch as in water treatment, foodprocessing etc. Existing genotoxicityassays are useful for evaluating the risks associated with the use of Nanoparticles. In this study, the mutagenicity of Copper Nanoparticle was assessed using standard assay, the Salmonella reverse mutation assay (Ames test). Seven different concentrations (0.005, 0.015, 0.05, 0.15, 0.5, 1.5 and 5 µL/mL) of this Nanoparticle were tested using five histidine deficient mutant tester strains of Salmonella typhimurium (i.e., TA1537, TA1535, TA98, TA100, and TA102) in the presence and absence of the S9 mixture. At all the concentrations tested, copper nanoparticles did not significantly increase the number of revertant colonies compared with the negative and positive control with or without S9 mixture
