TABLE 1.

Heat (56°C)-survival-parameter estimates for late-logarithmic-growth-phase (13-h) L. monocytogenes cells incubated at 37°C for 15 or 45 min in TPB at pHs 7.3 to 12.0

Treatment time (min)	TPB pH (±0.1)a	Eqn.b	(1 − f) least heat-sensitive fraction	β2 − least heat-sensitive fraction (min−1)	β1 − most heat-sensitive fraction (min−1)	β (min−1)	Pseudo r2c	Logistic D value (min)d
15	7.3	1				0.425 ± 0.021	0.973	6.92
	9.0	1				0.429 ± 0.014	0.987	6.85
	10.0	1				0.539 ± 0.029	0.968	5.45
	11.0	1				0.481 ± 0.004	0.999	6.11
	12.0	1				0.355 ± 0.020	0.958	8.28
	12.0e	1				0.350 ± 0.006	0.996	8.40
45	7.3	1				0.488 ± 0.013	0.991	6.02
	9.0	1				0.504 ± 0.014	0.991	5.83
	10.0	1				0.520 ± 0.014	0.991	5.65
	11.0	2	0.13	0.508 ± 0.011	0.789 ± 0.081		0.997	5.79
	12.0	2	0.2	0.205 ± 0.010	25.7 ± >100		0.969	14.30
	12.0e	1				0.355 ± 0.009	0.993	8.28

^aThe pH of TPB was adjusted using 1.0 N NaOH with noted exceptions. 

^bParameter estimates were obtained by fitting survival data to the appropriate logistic equation (Eqn.) by nonlinear regression. 

^cCalculated as 1 − (residual sum of squares/corrected total). 

^dCalculated as D = 2.94/β for equation 1 or D = (ln19)/β₂ for equation 2. 

^eThe pH was adjusted using 2.0 N NaOH.