Thermal Processing and Kinetics

At $121^\circ\text{C}$, a bacterial spore population is reduced from initial count $N_0 = 10^5$ to $N_t = 10^2$ in $t = 6.0\text{ minutes}$. Number of log cycles reduced is $\log_{10}(10^5 / 10^2) = 5 - 2 = 3$. The $D_{121}$-value $D = t / 3 = 6.0 / 3$ in minutes is: