The news around this, this thread, and similar on Reddit seem to be assuming a jump that isn't supported in this paper.
"The residue remaining after the rinse cycle varies between 1:250 to 1:667 for the dishwasher detergent and 1:2,000 to 1:10,000 dilutions for the rinse aid."
This is actually an uncited claim in the paper, and the paper authors did not test it.
"In the present study, we hypothesized that if the detergent and rinse aid residues are not completely removed, once dry, they may remain on the surface of the dishware."
But then they go on to only test what would happen to gut lining cells if most dishes most of the time had residue on them in such concentrations as they assume would be present, transfer to the food, and make it past the stomach.
This line of research really should have started with something like,
"we swabbed 50 recently washed and dried dishes from 25 different restaurants using different dish-washing machines. Here is the average concentration of detergent and rinse aid residue on the dry dishes".
I get that's not the study they wanted to do, of course; who wants to spend hours and days swabbing dry dishes when you have a decent reason to play with new biotech?
But that means the only thing this paper actually looked at is: IF there is residue on the dry dishes, and IF that remains in the assumed concentrations by the time you eat off of it, and IF all of that residue ends up attached to your food, and IF all those chemicals make it past your stomach, let's see what that might do to your gut lining.
Not a bad idea for a study, but definitely not what people on the internet are taking this to be.
The news articles are promoting that unsupported claim to an assumed fact that there is chemical residue on all the dishes people are eating from and that this is destroying people's gut lining. Most of the headlines around this are something to the effect of: "Commercial Dishwashers Destroy Protective Layer in Gut".
Which is pure sensationalism, the paper authors never claim this and this idea is not supported by present evidence.
I can smell detergent scent on my dishes after a wash and rinse, even if I don’t use rinse aid. Maybe my dishwasher’s rinse cycle isn’t very good: but if so I imagine that I’m not alone.
I agree with what you’re saying here in terms of the raw findings, but I wonder if as a society we’re approaching this question wrong. Specifically: if I proved that dishwasher detergents contained a toxic chemical (say: arsenic), shouldn’t dishwasher detergent makers now bear the burden of proof for demonstrating that it doesn’t remain on dishes? And isn’t it reasonable for people to treat this as major, worrying news just based on the precautionary principle?
Modern dishwashers use way less water, so you are likely using too much detergent. You can probably cut the amount in half. I actually run an extra sanitize cycle which is like an extra rinse I believe to help remove the extra residue. Older dishwashers in general use a lot more water which helps. Sometimes I run the tough cycle since it uses more water as well.
I use the pods most often but I've found that cascade platinum leaves more noticeable residue then quantum but I may actually switch to something else entirely. The problem is if I use anything besides these two my dishes don't get as clean. The pods are also difficult to chop in half.
I think the manufacturers need to create a low dose high efficiency detergent. There's probably a formula and I bet cascade platinum and the quantum are optimized for an older generation of washers that use more water.
I agree, caution still seems justified, whenever we find toxic effects of materials we might contact daily it's worth considering whether the risk that this is a real and present threat is worth the benefits of having those things around. Similar story with Teflon, plastic packaging and utensils, clothing detergents, surface cleaners, micro-beads in face products, cosmetics, talcum powder, deodorant, etc.
For this specific case, I'd still rather see the evidence that most dishwashers, when used according to manufacturer operating instructions (or even when used as most people operate them in practice) actually do leave enough dangerous chemical residue on the dishware to be a risk and that significant amounts of this stuff transfers to food before I'd say it's a claim the manufacturers have a burden of defending. Similar claims could be made about ceramics and glazing for instance, and the ceramics would harm us if ingested, but there's no evidence that ceramics from plates transfer to foods as we eat, even if we cut food on the plate with a knife. Of course, ceramics don't tend to dissolve readily in water either so we can presume detergents and rinse aids have some higher chance of transferring to food if present.
Of course the reality is, if enough people take the sensationalist headlines seriously, the manufacturers will have to defend it anyway; but this effect is what makes organization leaders assume most people are too stupid to hear the truth about nearly anything and the root cause of things like bad nutritional advice recycling over and over again.
Many people are still afraid of stuff like MSG, even though it occurs naturally in many foods and has been proven safe over and over again. The root cause of that scare was a science article in the New England Journal of Medicine back in 1968 which was sensationalized by the New York Times. Bad memes like "Chinese Restaurant Syndrome" are prevalent enough throughout the history of scientific literature to merit an equal portion of caution before reacting to any single paper with too little skepticism or too much drive to change our lifestyles or behaviors.
I think the gist of your response is that you think the standard should be “first prove it’s retained on dishes” before you remove a known harmful ingredient. I will reiterate that I disagree with this: the well-funded industry deploying the toxic ingredient should be responsible for proving that the toxic ingredient is washed clean. I feel this way for three reasons: (1) the industry chose the ingredient and thus should bear the burden of proving it’s safe, (2) the industry has more resources, (3) if this ingredient does prove dangerous, industry might select a new ingredient that is equally dangerous (and hence see point 1.) I don’t feel like your post provided me with much of a reason to change my opinion on this.
As far as MSG goes I’m not sure what that has to do with this issue. Clearly it would have been better if MSG had been well-studied early on, before concerns about it spread widely. This seems like an argument for investing in studies early. But even aside from that: this is not MSG. It’s a toxic ingredient that may or may not evaporate.
Btw, MSG is found naturally in a bunch of stuff, like the seaweed used in various parts of Chinese and Japanese cuisine. So it's not something a well funded industry invented like artificial sweeteners. (for which it seems no amount of study can stop the bad memes)
Much like yogurt, it's made by fermentation. Much like table salt, it was discovered to be delicious by people putting just about everything in their mouths back in the day. It can be said that MSG was in the process of being well-studied early on when the sensationalized news fouled up the whole process and made people unnecessarily afraid of something no more harmful than table salt.
Decades and tens to hundreds of papers later, the sensationalized story is still winning in the minds of people who don't understand how science works and don't know where most of the stuff around them comes from. This is the problem with overreacting to a headline. You might be doing yourself a favor health wise, possibly, but you might also be demanding millions of restaurants redesign their menus to feed you less healthy, less delicious food, for no good reason.
The problem is, you don't know. That's why it's okay to take a single paper with a grain of salt.
I think what you are asking for is generally the status quo actually. Industry does not generally choose ingredients so casually without any study at all. And regulators generally require prospective studies on possible harmful effects to people and environments before new compounds can be introduced to products people use all the time. That is most of what the FDA and EPA are up to.
The problem is, people can be wrong. Scientists have bias too. Sometimes people see trends in data not because it's valid but because that's what they were consciously or sub-consciously hoping to find. Even on review of the work by industry and regulatory panels, people still make mistakes. Products still sometimes have effects no one knew about or intended. On top of that, everything is lethal in sufficient quantities. Even water will kill you through electrolyte depletion if you drink enough a once.
My point is just that science is hard, studies are deliberately narrow and careful to try and add one tiny little fact to the pile of all human knowledge. And even then, most early findings turn out to be wrong in various ways or get refined in a way that makes excited reactions later seem overblown. It takes a long time to prove anything like the broad statements we tend to find in sensationalized news coverage. So while caution is fine, immediately assuming that one small study just recently published, yet to be replicated successfully, using a methodology that leaves a huge number of variables open to question between the lab environment and the real world use cases, is just not something to get too excited about.
Maybe the companies that work on rinse aids will want to follow up this line of research and answer some of those questions...but let's be honest, if you're already assuming the product is harmful based sensationalized news, are any follow up papers funded by the interested parties really going to change your mind? Are you even going to look for those papers six months to a year after you toss out your rise aid and demand your favorite restaurants do the same?
If you want to find the studies you would like industry to be doing, I'm sure they are available. Most of the scientific studies out there have something to do with testing products that exist or finding new things to make into new products.
It's just that most studies of anything at all are not terribly sensational. Like, how boring a headline is "dish soap company finds new detergent compound that binds to grease 2% better than the most commonly used compound, no immediately obvious side-effects, more study needed for FDA approval"?
To add to this. When I take dishes out of my dishwasher and rinse them manually, sometimes they feel slippery until I rinse the residue off them. I always wondered what that was. I think the detergent I use with my Miele (also made by them) includes a finishing agent, not sure. I will check and perhaps try something else for a while.
This line of research really should have started with something like,
I get that's not the study they wanted to do, of course; who wants to spend hours and days swabbing dry dishes when you have a decent reason to play with new biotech?But that means the only thing this paper actually looked at is: IF there is residue on the dry dishes, and IF that remains in the assumed concentrations by the time you eat off of it, and IF all of that residue ends up attached to your food, and IF all those chemicals make it past your stomach, let's see what that might do to your gut lining.
Not a bad idea for a study, but definitely not what people on the internet are taking this to be.
The news articles are promoting that unsupported claim to an assumed fact that there is chemical residue on all the dishes people are eating from and that this is destroying people's gut lining. Most of the headlines around this are something to the effect of: "Commercial Dishwashers Destroy Protective Layer in Gut".
Which is pure sensationalism, the paper authors never claim this and this idea is not supported by present evidence.