A Salmonella typhimurium reverse mutation standard plate incorporation study was conducted to evaluate whether a saline extract of Booster Gel Lot 70710-D and Daywhite 15% Lot 970701, Lot #70710-D & Lot A 970701, would cause mutagenic changes in histidine-dependent Salmonella typhimurium strains TA98, TA100, TA1535, TA1537, and TA1538 in the presence and absence of S9 metabolic activation. The methodology of Ames et al (1975) was followed using a saline extract.

The saline test article extract, at a dilution of 1:8, was found to be non-inhibitory to growth of tester strains TA98, TA100, TA1535, TA1537, and TA1538. Separate tubes containing 2ml of molten top agar supplemented with histidine-biotin solution were inoculated with 0.1ml of culture for each of five tester strains, and 0.1ml of the saline extract. A 0.5ml aliquot of S9 homogenate simulating metabolic activation was added when necessary. The mixture was poured across triplicate Minimal E plates. Parallel testing was also conducted with a negative control, and four positive controls. The mean number of revertants of the triplicate test plates were compared to the mean number of triplicate negative control plates for each of the five tester strains employed. The values (means) obtained for the positive controls were used as points of reference.

Under the conditions of this assay, the saline test article extract was not considered to be mutagenic to Salmonella typhimurium tester strains TA98, TA100, TA1535, TA1537, and TA1538. The negative and positive controls performed as anticipated.


CONCLUSION


Under the conclusions of this assay, the saline test article extract was not considered to be mutagenic to Salmonella typhimurium tester strains TA98, TA100, TA1535, TA1537, and TA1538.