Table 2.

Persistence times estimated using linear regression model for heat inactivation at 25, 56 and 65°C

Strain	Temperature	Slope (a)	y-Intercept (b)	x-Intercept (minute)	Virucidy (minute)
FRA2	25°C	0·006	5·25	NA	NA
	56°C	−0·16	5·09	30·7 [26·0; 35·2]	24·1
	65°C	−3·62	5·25	1·45 [1·0; 1·9]	1·1

Slope (a), y-intercept (b) and x-intercept values of the linear regression straight lines calculated from TCID₅₀ values (ND values in Table1 were not included in the calculation). Virucidy corresponded to the duration necessary to obtain a fourfold reduction of the titre in log₁₀. The values in brackets corresponded to the 99% confidence intervals. NA, not applicable. Each condition was performed in triplicates. The whole experiment was performed twice with similar results (data not shown).