Log Reductions Explained

 

In terms of infection control, ‘Log Reductions’ convey how effective a product is at reducing pathogens. The greater the log reduction the more effective the product is at killing bacteria and other pathogens that can cause infections.

 

 

During product efficacy testing, the microbiology laboratories count the number of colony forming units (CFUs) of the given pathogen present at the start of the test.  They then apply the disinfection product being tested, alongside a control product and wait the required test time before recounting the number of CFUs present.

The result of the difference between the control and the test product is then expressed as a Log reduction. For example, if the number of CFUs in the control was found to be 1,000,000 (or 106) and the end result using the product was only 1,000 (103), that would be a Log reduction of 3 or a reduction of 99.9%.

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