If a process achieves a 6-log reduction in a pathogen, by what factor has the microbial population decreased?

If a process achieves a 6-log reduction in a pathogen, by what factor has the microbial population decreased?

• A. 10^6
• B. 10^5
• C. 10^3
• D. 10^2

Answer: (A)

A six-log reduction means six orders of magnitude decrease in the microbial population. Each log step is a tenfold reduction, so six logs correspond to a factor of 10^6. In other words, the population is reduced by one million times (N final = N initial / 10^6). For context, five-log, three-log, and two-log reductions correspond to factors of 10^5, 10^3, and 10^2 respectively. Therefore, the correct factor is 10^6.

A six-log reduction means six orders of magnitude decrease in the microbial population. Each log step is a tenfold reduction, so six logs correspond to a factor of 10^6. In other words, the population is reduced by one million times (N final = N initial / 10^6). For context, five-log, three-log, and two-log reductions correspond to factors of 10^5, 10^3, and 10^2 respectively. Therefore, the correct factor is 10^6.