Sample Dose (µg/Plate)B Number of revertants/plate (mean  ± SE)D     TA98 TA100 TA102 Saliva 0C 38 ± 4 E 151 ± 9 E 449 ± 29 E   0.5 4 ± 1 0 ± 0 1836 ± 57 F   1 1 ± 0 13 ± 1 2098 ± 155 F Positive control A   1675 ± 0 F 484 ± 29 F 2151 ± 95 F Gastric 0C 38 ± 4 E 151 ± 9 E 449 ± 29 E   0.5 42 ± 3 61 ± 9 502 ± 21   1 44 ± 5 84 ± 4 468 ± 15 Positive control A   1675 ± 0 F 484 ± 29 F 2151 ± 95 F Duodenal + Bile 0C 38 ± 4 E 151 ± 9 E 449 ± 29 E   0.5 9 ± 2 13 ± 2 1800 ± 74 F   1 0 ± 0 54 ± 5 1699 ± 116 F Positive control A   1675 ± 0 F 484 ± 29 F 2151 ± 95 F Sequential 0C 38 ± 4 E 151 ± 9 E 449 ± 29 E   0.5 37 ± 1 166 ± 5 524 ± 31   1 38 ± 3 170 ± 10 473 ± 19 Positive control A   1675 ± 0 F 484 ± 29 F 2151 ± 95 F APositive Control: TA98-Daunomycin (6 μg/Plate); TA100-Sodium Azide (1.5 μg/Plate); TA102-Mitomycin C (0.5 μg/Plate). B Concentration based on 100×15-mm Petri dish containing 20 to 25 ml of MG agar. The doses of the tested mutagens were expressed as μg/plate (Maron and Ames, 1983; Mortelmans and Zeiger, 2000). C Negative control: Filter sterilised water. D Number of histidine revertants per plate: Mean values of at least three plates ± standard error (SE). E Numbers in italic, boldface and underlined represent the number of spontaneous revertants colonies for: TA98 (30-50), TA100 (120-200) and TA102 (117-530) (Maron and Ames, 1983). F Numbers in boldface represent two fold increase or more in the number of revertant colonies over the solvent controls (spontaneous revertants), which was an indication of a significant mutagenic response.

Table 1: The number of reverse mutants of S. typhimurium TA98, TA100 and TA102 after exposure to MMC Samples were analysed in the aqueous phase after extraction by the in vitro procedure.