As we briefly discussed on the main page, log reduction refers to the relative number of live pathenogens eliminated through sanitization or disinfection (cleaning) of a given environment. The number in the reduction value refers to the ‘number of nines’ in the reduction percentage. Log two reduction means that 99% of live microorganisms are eliminated, while log nine reduction indicates that 99.9999999% of specimens are neutralized by a given procedure.
What about a log reduction value of 2.5? We can infer that it reduces the number of live CFU by somewhere between 99% (log reduction two) and 99.9% (log reduction three), but is it really midpoint between them, or 99.45%? The short answer is no. The longer answer involves a small bit of math using the following formula.
P = (1 – 10-L)(100)
P: The percent reduction
L: The log reduction
For a log reduction value of 2.5, the formula offers the following calculations and results:
P = (1 – 10-L)(100)
P = (1 – 10-2.5)(100)
P = (1 – 0.00316227766)(100)
P = (.99683772234)(100)
P = 99.683772234
Log reduction of 2.5 indicates a kill rate of active CFU by 99.68%. In a room with ten thousand active specimens, the number remaining after treatment by a solution with a log reduction value of 2.5 would be less than or equal to thirty-two (32) specimens.
The log reduction of all pathogens against which SteraMist™ technology has been tested is no lower than six; in a room with ten thousand active specimens, a minimum of 99.9999% will be neutralized, leaving less than one survivor.