Comparison of Primary Models to Predict Microbial Growth by the Plate Count and Absorbance Methods

Table 2

Growth parameters and their 95% confidence limits and coefficients of determination (), SSE, and RMSE of fit obtained with different growth models for the average OD growth curves of Bacillus cereus INRA-AVTZ 415 at 30°C in BHI inoculating 10², 10⁴, and 10⁶ CFU mL⁻¹ shown in Figure 1(a).

Growth model	Initial concentration (CFU mL^−1)	Lag time (h)	Growth rate; (OD units h^−1)	(OD units)	(OD units)			SSE	RMSE
Three-phase linear	10^2	7.81; (7.68–7.94)	0.269; (0.253–0.285)	0.130; (0.042–0.217)	1.056		0.994	0.0034	0.0207
	10^4	5.47; (5.29–5.66)	0.304; (0.274–0.334)	0.140; (0.019–0.261)	0.999		0.989	0.0042	0.0268
	10^6	2.82; (2.68–2.95)	0.293; (0.273–0.312)	0.180; (0.027–0.332)	0.975		0.994	0.0032	0.0215
Gompertz	10^2	7.95; (7.87–8.03)	0.312; (0.301–0.329)	0.117; (0.109–0.124)	1.107; (1.095–1.120)		0.999	0.0166	0.0179
	10^4	5.50; (5.35–5.64)	0.342; (0.314–0.370)	0.118; (0.103–0.133)	1.078; (1.050–1.106)		0.996	0.0281	0.0283
	10^6	2.87; (2.69–3.04)	0.349; (0.315–0.382)	0.142; (0.119–0.166)	1.057; (1.019–1.095)		0.995	0.0252	0.0311
Logistic	10^2	8.01; (7.97–8.06)	0.313; (0.307–0.319)	0.105; (0.102–0.109)	1.104; (1.099–1.110)		0.999	0.0031	0.0077
	10^4	5.56; (5.47–5.65)	0.345; (0.329–0.360)	0.105; (0.096–0.150)	1.070; (1.056–1.085)		0.999	0.0081	0.0152
	10^6	2.87; (2.75–2.99)	0.347; (0.329–0.365)	0.114; (0.098–0.110)	1.066; (1.045–1.088)		0.999	0.0070	0.0164
Richards	10^2	8.00; (7.96–8.05)	0.303; (0.285–0.321)	0.106; (0.103–0.110)	1.104; (1.099–1.110)	0.911; (0.769–1.054)	0.999	0.0030	0.0076
	10^4	5.63; (5.54–5.72)	0.401; (0.373–0.429)	0.096; (0.086–0.100)	1.071; (1.058–1.084)	1.693; (1.257–2.130)	0.999	0.0060	0.0132
	10^6	2.85; (2.75–2.95)	0.420; (0.400–0.439)	0.071; (0.048–0.090)	1.099; (1.076–1.122)	2.490; (1.823–3.158)	0.999	0.0029	0.0108
Baranyi	10^2	7.80; (7.70–7.90)	0.275; (0.264–0.286)	0.155	1.047; (1.040–1.054)		0.999		0.0155
	10^4	5.40; (5.29–5.51)	0.307; (0.291–0.323)	0.141	1.020; (1.010–1.030)		0.999		0.0178
	10^6	2.76; (2.66–2.87)	0.312; (0.298–0.326)	0.152	1.015; (1.006–1.023)		0.999		0.0148