a question about bacteria

[milly143]

this may be in the wrong plae but I was wondering, if products like Dettol can kill 99.9% of bacteria, why can't it kill 100%?

[Loosehead]

It probably does, it's just the company protecting itself against potential litigation

[j2buttonsw]

I think it is due to death rate dynamics: There is a mathematical model that plots death rate with concentration of dettol (for instance) which one can extrapolate/intrapolate. It looks rather like a growth curve but going in the opposite direction eg it is a exponentially decreasing curve: all living, 1/2 living, 1/4 living, 1/8 living, 1/16 living, 1/32 living etc etc. The problem with the mathematical model is that it tends to zero without actually reaching zero hence the 99.9% bit. According to the model there will never be a concentration of dettol that will kill 100%.

[jake-the-peg]

Given that we've found bacteria that seem to thrive in nuclear reactors - I'd certainly not be claiming that my disinfectant can accomplish what a PWR cannot! bacteria can be tough things

[Calvesy]

Life is always evolving, and we are all here because every one of our ancestors back to the dawn of time survived to reproduce in spite of the environment. It is possible that a mutation in an individual bacterium will make it resistant to Dettol, or even addicted, and you will breed a superbug that will have no competition. My advice is to be squalid and keep you immune system on its toes, otherwise it gets bored and attacks you with Eczema and MS just to pass the time of day.

[tracymort]

Yeah i can't stand that advert, spraying everything your child touches! No wonder they have all these allergies! Your immune system needs practise.

[Peter Pedant]

 

some bacteria sporulate and produce spores and Dettol doesnt get them, and also i am not sure if Dettol does in mycobacteria (TB) - perhaps a dettol freak will tell us

[Tweed]

Good point traceymort, our immune systems are becoming complacent, they don't have as much to do these days. A bit off the point but WTF.

[landie]

I agree with Loosehead, they would be bold indeed to claim 100%, even if the product was able to.

[Hamish]

Killing a mass population of something as simple as bacteria (an thier spores) is difficult. Whilest I have no worried about getting detol on my hands (so long as I can wash it off) I wouldn't like to get any of the agents used for sterilising medical equipment on me - yet even these are not perfect! Why? not sure - above what has already been said - it probably has to do with bacteria in micro pours and groves which wont be easily dosed .....

Just for Jake-the-peg simple life forms are not easily killed by irradiation etc. Apparently a scorpian can survive (the gamma radiation) grnd zero at a nucear attack. You can also freeze them in an ice block and defrost them in a microwave and the will still be alive and kicking (dont try this at home!)