Temperature at which bacteria start to die: 65C
Recommended temperature of the hot water supply in domestic premises: 60C
60C = 140F. The legal requirement for domestic hot water in California is only 120F.
Hot water for dishwashing is great because it makes it easier to get rid of anything greasy, but it's the dish soap combined with water that's doing the real work of keeping us safe. Ever notice how the phrase is always "wash with soap and water"? Soap diluted with water breaks up microbes and the chemical bonds that make them stick to things. One of the few things I learned in high school chemistry that stuck. It's why you can wash your hands with soap and cold water to kill the covid coronavirus, among many other things.
You can sterilize stuff with heat, but not easily, and not with the hot water you're getting out of the kitchen faucet. Sterilization takes place at much higher temperatures. But sterilization is not what's required, at least not by US food service standards -- they want things to be sanitized and in some cases disinfected.
Ok I will go with sanitation. The liquid does, as I said some of the job. Hot water does the rest. So water can be at the top end of the danger zone and in combination with the liquid do the job. As to other parts of the world. We live in a sanitised environment compared to others. Our bodies are more at risk than locals or long term residents. When I went to both Ghana and India UK government advice was not to drink water or eat salad washed in it. Or even ice cream that had been scooped. Use bottled water.
Helping to activate the soap and dissolve grease - as well as being nice on your hands!
In Africa we didn't drink bottled water (it wasn't available anyway) but we did use a water filter. Our well was quite deep and the soil was sandy; this helped too although we weren't the well's only users by any means and there was no guarantee that other folks' buckets and ropes were clean, nor that animals weren't sniffing around the well-head.
I think the reason my grandparents, parents and us children when visiting survived on water variously drawn from mountain streams, roadside puddles and ponds into which cattle occasionally fell, is that it was usually* consumed as tea. There was always a large kettle pumping quietly on the back of the range from which hot water would be drawn to, as my grandmother would say 'rench the vessels'.
*but not invariably: my mother would pine fondly for 'spring water' as opposed to the nasty stuff you got out of taps.
What is hot water doing when it's not hot enough to kill bacteria?
It softens and melts fats, and is better at dissolving things than cold water.
Don't underestimate the necessity of a good scrub, though. I had a flatmate at university who was under the impression that you could leave something to soak in soapy water, and then it would be magically clean. I pointed out the obvious baked-on lumps of food on the dish he said he'd cleaned, and we went through the whole "but I washed it!" "But look - you can see the food!" discussion.
I did eventually manage to persuade him of the merits of a little elbow grease, fortunately.
QI advises don’t rinse dishes before you put them in the dishwasher, as the detergent has enzymes in it that won’t work without something to latch on to. This made me feel much better about my lazy habits.
QI advises don’t rinse dishes before you put them in the dishwasher, as the detergent has enzymes in it that won’t work without something to latch on to. This made me feel much better about my lazy habits.
Mrs Karlt however has Views on the dishwasher drain being clogged by food fragments, and unlike the QI elves I share a house with her.
QI advises don’t rinse dishes before you put them in the dishwasher, as the detergent has enzymes in it that won’t work without something to latch on to. This made me feel much better about my lazy habits.
Mrs Karlt however has Views on the dishwasher drain being clogged by food fragments, and unlike the QI elves I share a house with her.
Yes, much depends on the dishwasher ability to deal with those food fragments.
I think the reason my grandparents, parents and us children when visiting survived on water variously drawn from mountain streams, roadside puddles and ponds into which cattle occasionally fell, is that it was usually* consumed as tea. There was always a large kettle pumping quietly on the back of the range from which hot water would be drawn to, as my grandmother would say 'rench the vessels'.
*but not invariably: my mother would pine fondly for 'spring water' as opposed to the nasty stuff you got out of taps.
In a number of Karoo towns (the word Karoo means 'land of thirst') the only water available is sour and brackish, cloudy with sediment and offputting to visitors. Those who have grown up with it loathe municipal tap water in cities or sterile bottled water because it doesn't have the right tang.
Our tap water is sourced from one of the lochs (it is treated) but for whatever reason it is some of the hardest tap water in Scotland and the limescale is horrendous. We're planning a water softener when we move into our own house.
A new wrong thing. My catering senses are screaming the current Fairy Washing Up Liquid add here in the UK. You should not wash crockery, cutlery and pans in cool water. You need hot water to sterilise the stuff. Anti Bacterial liquids do not do the full job. Avoid food poisoning, wash up in hot water.
I have that very Fairy Liquid and use cold water sometimes and I haven't died yet or been ill. But then I do wash up under running water, whether hot or cold. Washing up bowls are good for soaking beforehand but quite quickly accumulate small particles of detritus once the process of washing up starts.
Or, if not regulators then other brands. "Cleans better than other leading brands" is a common enough advertising approach. If that can be backed up by some data - bacterial counts on items washed in multiple products with their brand showing lower bug counts would do it, with "hand washing at recommended 40C compared to the 'lower temperature' claim of other brands" in the small print to cover them.
Comments
60C = 140F. The legal requirement for domestic hot water in California is only 120F.
Hot water for dishwashing is great because it makes it easier to get rid of anything greasy, but it's the dish soap combined with water that's doing the real work of keeping us safe. Ever notice how the phrase is always "wash with soap and water"? Soap diluted with water breaks up microbes and the chemical bonds that make them stick to things. One of the few things I learned in high school chemistry that stuck. It's why you can wash your hands with soap and cold water to kill the covid coronavirus, among many other things.
You can sterilize stuff with heat, but not easily, and not with the hot water you're getting out of the kitchen faucet. Sterilization takes place at much higher temperatures. But sterilization is not what's required, at least not by US food service standards -- they want things to be sanitized and in some cases disinfected.
In Africa we didn't drink bottled water (it wasn't available anyway) but we did use a water filter. Our well was quite deep and the soil was sandy; this helped too although we weren't the well's only users by any means and there was no guarantee that other folks' buckets and ropes were clean, nor that animals weren't sniffing around the well-head.
*but not invariably: my mother would pine fondly for 'spring water' as opposed to the nasty stuff you got out of taps.
Which is why it is possible to use cooler water to wash up, if the detergent is formulated to work at those temperatures.
It softens and melts fats, and is better at dissolving things than cold water.
Don't underestimate the necessity of a good scrub, though. I had a flatmate at university who was under the impression that you could leave something to soak in soapy water, and then it would be magically clean. I pointed out the obvious baked-on lumps of food on the dish he said he'd cleaned, and we went through the whole "but I washed it!" "But look - you can see the food!" discussion.
I did eventually manage to persuade him of the merits of a little elbow grease, fortunately.
Mrs Karlt however has Views on the dishwasher drain being clogged by food fragments, and unlike the QI elves I share a house with her.
In a number of Karoo towns (the word Karoo means 'land of thirst') the only water available is sour and brackish, cloudy with sediment and offputting to visitors. Those who have grown up with it loathe municipal tap water in cities or sterile bottled water because it doesn't have the right tang.
I have that very Fairy Liquid and use cold water sometimes and I haven't died yet or been ill. But then I do wash up under running water, whether hot or cold. Washing up bowls are good for soaking beforehand but quite quickly accumulate small particles of detritus once the process of washing up starts.
Seems to me a regulatory agency would have said something if the ad was promoting a practice that's truly dangerous.
Indeed.