How to measure Log reduction
The reduction of pathogens is measured in Log – Logarithm.
“Log reduction stands for 10-fold (one decimal) or 90% reduction in numbers of live bacteria.”
At a 4 Log reduction, the number of pathogens is 10,000 times less.
5Log reduction means the number of pathogens is reduced, times 100,000.
[Source: healthy facilities institute, Log reduction chart]
Log reduction
1-Log reduction: fewer bacteria reduced by a factor 10
5-Log reduction: fewer bacteria reduced by a factor 100,000
