Hand Sanitisers are meant to reduce germs on our hands to prevent ourselves and others from getting sick, but how do we know if they are actually effective? Our options are either the manufacturers log reduction claim based on laboratory tests, or we can make assumptions based on the alcohol percentage. (See our previous blog on alcohol percentage here)
What is “Log Reduction”?
It a measure of the reduction of germs expressed as a ratio, often shown as either a percentage such as 99% or as a log reduction such as 2-Log reduction. A 1-Log reduction is a 10-fold decrease, and as an example from 100 germs a 1-log reduction would reduce this by 10 leaving 90 germs, a 2-log reduction removes another 10-fold so 99%, 3-log reduction is therefore 99.9% and so on.. (Wikipedia has a great mathematical definition here)
Why is this important to a hand sanitiser?
If our reason for using a hand sanitiser is to kill the germs on our hands, then why use one that that only kills some of the germs?
Knowing that there could be over 1 million germs on a pin head and that you may only need between 10 and 100 cells of the common E. coli O157:H7 to make you very sick, we then realise how important the actual germ reduction or effectiveness of the hand sanitiser is.
From the graph below we start at 1million CFU’s (Colony Forming Units – See Wikipedia again for definition). CFU’s are actual viable cells that are live and able to multiply and infect. We could use a hand sanitiser that provides a 99.99% or 4-log reduction to hopefully reduce that 1 million to about 100 CFU’s – but this could still leave enough germs to make us sick. A 99.999% reduction or 5-Log reduction is better, leaving just 10 CFU’s.
However, if you are going to the trouble of buying a hand sanitiser, making it available to your staff and customers, and encouraging everyone to use it, why would you not go for one that provides a 99.9999% or 6-Log reduction? Our S-7 SMARTSAN Hand Sanitiser 70% not only provides a 99.9999% reduction, but feels great to use, and is not sticky.
It is important to make sure to use the correct amount of hand sanitiser to make sure your hands are wet for at least 15-20 seconds.
