Table 2

Sample	Dose (µg/Plate)	Number of revertants/plate (mean ± SE)^C
Gastric (pH 1.07)	0^B	467 ± 12 ^D
	0.5	505 ± 20
	1	424 ± 8
Positive control ^A		1223 ± 117^E
Gastric (pH 7.4)	0^B	467 ± 12 ^D
	0.5	510 ± 11
	1	493 ± 27
Positive control ^A		1223 ± 117 ^E
Sequential (pH 5.8)	0^B	467 ± 12 ^D
	0.5	507 ± 8
	1	475 ± 27
Positive control ^A		1223 ± 117 ^E
Sequential (pH 7.5)	0^B	467 ± 12 ^D
	0.5	511 ± 12
	1	480 ± 5
Positive control ^A		1223 ± 117 ^E

^A Positive Control for TA102- Mitomycin C (0.5 μg/plate).
^B Negative control: Filter
sterilised water.
^C Number of histidine revertants per plate: Mean values of at least three plates ± standard error (SE).
^D Numbers in italic, boldface and underlined represent the number of spontaneous revertants colonies for TA102 (117-530).
^E 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 2: The number of reverse mutants of S. typhimurium TA102 after exposure to MMC Samples were analysed in the aqueous phase after extraction by the in vitro procedure (buffered and un-buffered samples).