Practice question

Question

A batch sterilizer is being operated at 121 ᵒ C for sterilizing a medium containing microbial cells. Assume that the thermal deactivation of cells is a first order process with a death rate constant of 0.69 min ⁻¹ at 121 ᵒ C. If the initial concentration of microbes in the medium is 1010 cells m ⁻³ , the time taken to reduce the microbial load to a final concentration of 10 cells m ⁻³ is _________ min. (rounded off to the nearest integer)