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> As a microbiologist I'm aware that what looks clean can have leftover residue. How are you measuring cleanliness out of a dishwasher? I'm guessing by eye, the same way you're measuring hand-washed dish cleanliness.

So how are you measuring, if not by eyeballing it? Can you swab it and check for microbes? Did you?

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pazimzadeh 2 days ago | parent [-]

Why would that matter? I'm not the one who stated opinions as fact:

> If you can avoid those 5 mistakes, a dishwasher will always way out-perform hand-washing

> Even if you think it's clean by hand, chances are there's far more residual residue and bacteria you can't see that a dishwasher wouldn't have any trouble with.

The inverse statement is just as likely to be true depending on the shape of the dish used, where it's placed in the dish-washer, etc.. You think just because the corners of a weirdly shaped dish doesn't have obvious gunk after coming out of the dishwasher that they are clean? Well, I trust my hand scrubbing method more since I don't have a camera to see where and for how long the water landed in the dishwasher.

You could swab a plate, do a dilution series and count colony forming units but there's no guarantee that the growth conditions of your petri dish will reflect what can grow in your body (i.e. will the spores germinate in your petri dish?)

What is well known is that washing with soap trumps heat (except 120+ degrees celsius), and you don't need to kill bacteria for a surface to be clean (in fact it's better to wash them off than to kill them). The fact that hand-washing is better for scrubbing corners with soap is obvious. Case in point, this burnt/sticky rice leftover on a pot that I stuck in the dishwasher a few hours ago as a test: https://imgur.com/a/wfnxMnZ

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yjftsjthsd-h 2 days ago | parent [-]

You did in fact make several claims of fact, and then followed up with an appeal to authority as a microbiologist. Having those credentials means you probably could have verified your claims, but you don't appear to have done so, so we get to hand-wave at each other.

> What is well known is that washing with soap trumps heat (except 120+ degrees celsius)

The dishwasher uses heat and soap. And it sprays things off, while we're at it.

> The fact that hand-washing is better for scrubbing corners with soap is obvious. Case in point, this burnt/sticky rice leftover on a pot that I stuck in the dishwasher a few hours ago as a test

I will happily agree that hand washing tends to win on mechanical grounds. I think that if the machine can spray off the dishes to the point of being visually clean then it probably left them sanitized as well (again, hot water and soap and spraying is compelling to me), but if there's stuff stuck on the dishes then yes obviously a person scraping it off is going to be better at removing it.

	▲	pazimzadeh a day ago \| parent [-]
		I find it hard to believe that you're still doubling down but only selectively detecting unsupported "claims of fact" without support especially since I made weaker, more situational claims. The original poster commented: > machines wash 1000 times better than hand ever could, uses less water, and doesn’t dry out your hands "Ever could"? "1000 times"? And yet you have a problem with me saying hand-washing CAN be better when have dishes with corners or need to wash both sides of the dish. The next commenter said: > Even if you think it's clean by hand, chances are there's far more residual residue and bacteria you can't see that a dishwasher wouldn't have any trouble with I invoked being a microbiologist to make the point that I'm already aware of the fact that looking clean doesn't equal being clean. None of my arguments rely on my authority as a microbiologist. Anyone with decent reading comprehension can evaluate the broken logic: he's mixing up the fact that cleanliness is not just what something looks like with the idea that the dishwasher must do a better job than hand-washing because you can't tell if something is really clean or not. That makes no sense, and seems to be some kind of appeal to technology or modernity. > I think that if the machine can spray off the dishes to the point of being visually clean then it probably left them sanitized as well This is the exact point that the guy was saying is NOT the case, and as a microbiologist I agreed with him even though it's irrelevant to the argument since neither of us has tested the dishes. >The dishwasher uses heat and soap. And it sprays things off, while we're at it. My whole point was that soap and mechanical washing trump heat. My faucet sprays water, and I can evaluate the cleanliness without waiting 2 hours to see if the probabilistic machine jet spray left residue on my dishes or not.