Yet Another Cycling Forum
Off Topic => The Pub => Topic started by: Jaded on 27 March, 2021, 11:03:27 pm
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From what I have seen, every cleaning product that claims to kill bacteria (and sometimes viruses) will kill 99.9% of the nasties. Not 99% or 99.99%, but exactly 99.9%
Several thoughts come to mind.
Is that figure testable?
Do people realise that all you need for a superbug is 0.1% or far less, to be resistant and to multiply?
How is it that every cleaning product, almost without exception, has the same efficacy?
What is the efficacy of boring cheap stuff like soap?
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What is the efficacy of boring cheap stuff like soap?
99.99%, obv, but there's no mileage in advertising that.
ETA - $ome% appears to be the answer - https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3037063/
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I've never been sure whether it means "effective against 99.9% of species of nasties" or "will kill 99.9% of the organisms in a given sample". The latter leaves a lot of questions vis what organism, concentration, time period, etc.
I believe there are standards for categorising disinfectants by relative efficacy against standard organisms compared to simple chemicals (acids, oxidisers and the like). Sort of thing that the stuff used in labs and hospitals will have gone through, but probably not your lemon-scented Frish (other than perhaps as an advertising standards thing).
Killing bacteria by b0rking the cell membrane isn't rocket SCIENCE, and pretty much anything soapy will do it. Spores and things can be sturdier.
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I think you are on to something. See if you can rework the claim, inserting "who expressed a preference" into it.
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But it will only kill 8 out of 10 cats, trufax.
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I think you are on to something. See if you can rework the claim, inserting "who expressed a preference" into it.
Yes, that is a good point. I’ve spent the last year hearing how the Cronavirus is making choices about its next course of action.
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Obviously because ninety-nine and a half just won’t do (https://youtu.be/zdrC3f4SFpk).
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If it’s not five nines effective I’m not interested.
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Obviously because ninety-nine and a half just won’t do (https://youtu.be/zdrC3f4SFpk).
So that's who they are.
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We were told by the NHS and/or WHO at the beginning of The Current Times that soap and water is more effective than hand sanitizers.
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The reduction of a bacteriological or viral load is often expressed as a log reduction e.g. 2 log (99% or 1 in 100 surviving), 3 log (99.9% or 1 in 1,000 surviving), or 4 Log (99.99% or 1 in 10,000 surviving). Therefore this will based on the testing protocols and then converting it into units that the public can understand.
In my industry regulators in other countries will give each step in the treatment process a log credit for the reduction in the contamination. So the dose of UV light applied will be defined by the target species and the number of log reductions required.
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Aren’t the bug killing ingredients a choice of about 3 in all the products? Soap or bleach maybe. So it’s no great surprise that they’re similarly effective. The ones that are less good are advertised for their smell, shine giving properties, humorous name, sexy person in the advert, or price instead.
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If it’s not five nines effective I’m not interested.
:thumbsup:
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The reduction of a bacteriological or viral load is often expressed as a log reduction e.g. 2 log (99% or 1 in 100 surviving), 3 log (99.9% or 1 in 1,000 surviving), or 4 Log (99.99% or 1 in 10,000 surviving). Therefore this will based on the testing protocols and then converting it into units that the public can understand.
In my industry regulators in other countries will give each step in the treatment process a log credit for the reduction in the contamination. So the dose of UV light applied will be defined by the target species and the number of log reductions required.
That's useful. Thanks.
1 in 1,000 is still a hell of a lot of pathogens.
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1 in 1,000 is still a hell of a lot of pathogens.
True, in numerical terms
The missing number is the risk of harm / death per unit unwashed pair of hands covered in germs
Depends very much on what is in circulation, and where you have put said hands of course
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Some cleaners even have small print that specifies the time. 15 minutes was the last one I checked (Method, I think, which uses lactic acid, IIRC) -- I presume most people just spray and wipe, when really you need to leave it to work for a while.
Sam
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Does soap and water kill pathogens or just wash them off your hands ? I thought the idea was that the soap and water removed the bug filled greasy layer on your skin (and your skin then produces a fresh new greasy layer).
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Does soap and water kill pathogens or just wash them off your hands ? I thought the idea was that the soap and water removed the bug filled greasy layer on your skin (and your skin then produces a fresh new greasy layer).
Surfactants damage the cell membrane of bacteria in much the same way they remove grease. Efficacy against spores and viruses varies.
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The reduction of a bacteriological or viral load is often expressed as a log reduction e.g. 2 log (99% or 1 in 100 surviving), 3 log (99.9% or 1 in 1,000 surviving), or 4 Log (99.99% or 1 in 10,000 surviving).
I didn’t understand your arithmetic until I realised it is because we went completely organic a couple of years ago and now only use natural logarithms.
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The reduction of a bacteriological or viral load is often expressed as a log reduction e.g. 2 log (99% or 1 in 100 surviving), 3 log (99.9% or 1 in 1,000 surviving), or 4 Log (99.99% or 1 in 10,000 surviving). Therefore this will based on the testing protocols and then converting it into units that the public can understand.
In my industry regulators in other countries will give each step in the treatment process a log credit for the reduction in the contamination. So the dose of UV light applied will be defined by the target species and the number of log reductions required.
That's useful. Thanks.
1 in 1,000 is still a hell of a lot of pathogens.
Especially given, for example, E. Coli has a doubling time of 20 minutes in favourable conditions so you could get a million-fold growth in 3 hours...
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We are all doomed, doomed I’m telling ye.
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Conditions in average kitchens are favourable to bacterial growth in some locations but not THAT many.
CLEAN dry surfaces won't let many bugs flourish; they need food and water, but not necessarily air.
Wet dishcloths are often warm and laden with food. Wash regularly (pref HOT) & dry or use paper towels.
Moist food should be refrigerated, frozen or eaten ASAP. It should not be hanging about in a warm kitchen.
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The reduction of a bacteriological or viral load is often expressed as a log reduction e.g. 2 log (99% or 1 in 100 surviving), 3 log (99.9% or 1 in 1,000 surviving), or 4 Log (99.99% or 1 in 10,000 surviving). Therefore this will based on the testing protocols and then converting it into units that the public can understand.
In my industry regulators in other countries will give each step in the treatment process a log credit for the reduction in the contamination. So the dose of UV light applied will be defined by the target species and the number of log reductions required.
That's useful. Thanks.
1 in 1,000 is still a hell of a lot of pathogens.
Especially given, for example, E. Coli has a doubling time of 20 minutes in favourable conditions so you could get a million-fold growth in 3 hours...
I'm not convinced. Shouldn't that be 2^9 = 512-fold growth?
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The reduction of a bacteriological or viral load is often expressed as a log reduction e.g. 2 log (99% or 1 in 100 surviving), 3 log (99.9% or 1 in 1,000 surviving), or 4 Log (99.99% or 1 in 10,000 surviving). Therefore this will based on the testing protocols and then converting it into units that the public can understand.
In my industry regulators in other countries will give each step in the treatment process a log credit for the reduction in the contamination. So the dose of UV light applied will be defined by the target species and the number of log reductions required.
That's useful. Thanks.
1 in 1,000 is still a hell of a lot of pathogens.
Especially given, for example, E. Coli has a doubling time of 20 minutes in favourable conditions so you could get a million-fold growth in 3 hours...
I'm not convinced. Shouldn't that be 2^9 = 512-fold growth?
... or 7 hours.
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The reduction of a bacteriological or viral load is often expressed as a log reduction e.g. 2 log (99% or 1 in 100 surviving),
Yes I've visited those lavs, too, where the last bastard was either proud of his production "They are beautiful, I'll leave them there for everyone to enjoy" or plain lazy. Whichever, I'm impressed there's a formula to describe.
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The reduction of a bacteriological or viral load is often expressed as a log reduction e.g. 2 log (99% or 1 in 100 surviving), 3 log (99.9% or 1 in 1,000 surviving), or 4 Log (99.99% or 1 in 10,000 surviving). Therefore this will based on the testing protocols and then converting it into units that the public can understand.
In my industry regulators in other countries will give each step in the treatment process a log credit for the reduction in the contamination. So the dose of UV light applied will be defined by the target species and the number of log reductions required.
That's useful. Thanks.
1 in 1,000 is still a hell of a lot of pathogens.
Especially given, for example, E. Coli has a doubling time of 20 minutes in favourable conditions so you could get a million-fold growth in 3 hours...
Hence why having started with a count in the raw water we aim for a log reduction in the filtration, a further log reduction in a second stage filtration, 3.5 log reduction in the UV disinfection and a further 4 log reduction in the chlorine contact tank. By the time you add that up the chances of there being a surviving pathogen to repopulate the water is the influent concentration / 10^9.5. Add to that daily sampling of the water and culturing it in the lab to confirm it is clean and I trust the water from my tap more than I trust the cleanliness of the glass I am filling. :-[
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The reduction of a bacteriological or viral load is often expressed as a log reduction e.g. 2 log (99% or 1 in 100 surviving), 3 log (99.9% or 1 in 1,000 surviving), or 4 Log (99.99% or 1 in 10,000 surviving). Therefore this will based on the testing protocols and then converting it into units that the public can understand.
In my industry regulators in other countries will give each step in the treatment process a log credit for the reduction in the contamination. So the dose of UV light applied will be defined by the target species and the number of log reductions required.
That's useful. Thanks.
1 in 1,000 is still a hell of a lot of pathogens.
Especially given, for example, E. Coli has a doubling time of 20 minutes in favourable conditions so you could get a million-fold growth in 3 hours...
Hence why having started with a count in the raw water we aim for a log reduction in the filtration, a further log reduction in a second stage filtration, 3.5 log reduction in the UV disinfection and a further 4 log reduction in the chlorine contact tank. By the time you add that up the chances of there being a surviving pathogen to repopulate the water is the influent concentration / 10^9.5. Add to that daily sampling of the water and culturing it in the lab to confirm it is clean and I trust the water from my tap more than I trust the cleanliness of the glass I am filling. :-[
Admit it, you only do all that just to wind the homeopaths up.
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The reduction of a bacteriological or viral load is often expressed as a log reduction e.g. 2 log (99% or 1 in 100 surviving), 3 log (99.9% or 1 in 1,000 surviving), or 4 Log (99.99% or 1 in 10,000 surviving).
I didn’t understand your arithmetic until I realised it is because we went completely organic a couple of years ago and now only use natural logarithms.
The bad jokes thread is that way --->
Your coat is over there.
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Hence why having started with a count in the raw water we aim for a log reduction in the filtration, a further log reduction in a second stage filtration, 3.5 log reduction in the UV disinfection and a further 4 log reduction in the chlorine contact tank. By the time you add that up the chances of there being a surviving pathogen to repopulate the water is the influent concentration / 10^9.5. Add to that daily sampling of the water and culturing it in the lab to confirm it is clean and I trust the water from my tap more than I trust the cleanliness of the glass I am filling. :-[
I take it you work in a water works? Are you using chloramine or chlorine, out of professional interest?
Sam
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The reduction of a bacteriological or viral load is often expressed as a log reduction e.g. 2 log (99% or 1 in 100 surviving), 3 log (99.9% or 1 in 1,000 surviving), or 4 Log (99.99% or 1 in 10,000 surviving). Therefore this will based on the testing protocols and then converting it into units that the public can understand.
In my industry regulators in other countries will give each step in the treatment process a log credit for the reduction in the contamination. So the dose of UV light applied will be defined by the target species and the number of log reductions required.
That's useful. Thanks.
1 in 1,000 is still a hell of a lot of pathogens.
Especially given, for example, E. Coli has a doubling time of 20 minutes in favourable conditions so you could get a million-fold growth in 3 hours...
Hence why having started with a count in the raw water we aim for a log reduction in the filtration, a further log reduction in a second stage filtration, 3.5 log reduction in the UV disinfection and a further 4 log reduction in the chlorine contact tank. By the time you add that up the chances of there being a surviving pathogen to repopulate the water is the influent concentration / 10^9.5. Add to that daily sampling of the water and culturing it in the lab to confirm it is clean and I trust the water from my tap more than I trust the cleanliness of the glass I am filling. :-[
Admit it, you only do all that just to wind the homeopaths up.
Teh Mr Hall made me dun a roffle :thumbsup:
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Hence why having started with a count in the raw water we aim for a log reduction in the filtration, a further log reduction in a second stage filtration, 3.5 log reduction in the UV disinfection and a further 4 log reduction in the chlorine contact tank. By the time you add that up the chances of there being a surviving pathogen to repopulate the water is the influent concentration / 10^9.5. Add to that daily sampling of the water and culturing it in the lab to confirm it is clean and I trust the water from my tap more than I trust the cleanliness of the glass I am filling. :-[
I take it you work in a water works? Are you using chloramine or chlorine, out of professional interest?
Sam
I am a process engineering consultant in WTW. My current client operates a free chlorine network. Using either Chlorine Gas or Sodium Hypochlorite depending on the site consumption and surroundings. The two forms (Chlorine and chloramine) should not be mixed and a company that operates both had better have good delineation of the supply zones for each.
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From what I understand, it is a question of no product being able to kill 100% of all bacteria within a given period of time. So long as you keep the concentration low enough, the bacteria will not have enough of a hold to grow to a dangerous level within another amount of time.
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The reduction of a bacteriological or viral load is often expressed as a log reduction e.g. 2 log (99% or 1 in 100 surviving), 3 log (99.9% or 1 in 1,000 surviving), or 4 Log (99.99% or 1 in 10,000 surviving). Therefore this will based on the testing protocols and then converting it into units that the public can understand.
In my industry regulators in other countries will give each step in the treatment process a log credit for the reduction in the contamination. So the dose of UV light applied will be defined by the target species and the number of log reductions required.
That's useful. Thanks.
1 in 1,000 is still a hell of a lot of pathogens.
Especially given, for example, E. Coli has a doubling time of 20 minutes in favourable conditions so you could get a million-fold growth in 3 hours...
I'm not convinced. Shouldn't that be 2^9 = 512-fold growth?
Whoops! Well spotted!