For many years now, I carry in my sling bag a small bottle of hand sanitiser. I would use it before meals or after doing some work with my hands. It gives me a peace of mind.
In the last two or three years, I switched to Dettol's hand sanitiser as it is the only one that did not leave a sticky feeling after use. The stickiness from using hand sanitisers is what puts off some people. Dettol's formula solved that problem although it costs more.
Today, while driving to work, I saw a large bus ad announcing that Dettol's hand sanitiser kills 99.9% of all bacteria. I guess this claim must be on the bottle too but I never really bothered to think about it before. 99.9% of all bacteria? What are the 0.1% of bacteria that remain alive and well?
Is that statement just a quantitative one which means that the sanitiser kills all types of bacteria but some are lucky enough to fall through the cracks? Or is the statement a qualitative one which means it kills 99.9% of all types of bacteria but 0.1% of bacteria types are so strong that they could resist elimination? I would be very worried if 0.1% of bacteria types are strong enough to resist elimination!