TABLE 2.

Linearity of RTi-PCR C_T values versus numbers of CFU of L. monocytogenes organisms per gram of cooked ham^a

Expt	Treatment	R2	E
1	F1	0.987	1.09
	F2	0.984	1.02
	F3	0.994	0.83
2	F1	0.967	1.21
	F2	0.998	1.02
	F3	0.994	1.01

^aLinearity persisted along 4 logarithmic units. R² indicates the regression coefficient. PCR efficiency (E) is obtained from the formula E = 10^−1/s −1, where S is the slope (13, 18). Experiments 1 and 2 correspond to two independent experiments. F1, F2, and F3 indicate the three different pre-PCR filtration steps: no filtration (F1), filtration through 22- to 25-μm-pore-size filters (F2), and filtration through 11-μm-pore-size filters (F3).