Is there some way to seal or coat a print that would be used for holding food to protect the food from micro contaminants. Like a coating of wax or something else that would clean easily and be safe to use.
I did see a post about food safe PLA/PETG on Amazon, that i will read more of, but I’d like to know if there are any sprays or coatings that can give it like a water proofing but for food so the colour dye doesn’t run and leak into the food.
i was thinking of printing a nice bowl that would hold potato chips/ popcorn and other food, that wouldn’t be in contact for long periods, only till they are eaten.
Remember the way how a FDM printer works: The object will be printed in layers. So beside of the “food-safe”-status of the piece itselfs, you will have a lot of micro openings in it - perfect for all kinds of germs.
I have printed some parts for the kitchen and to transport some pieces with PETG to be able to clean it in the dishwasher. However, I would not say, it is “food-safe”.
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You’d probably want to do food grade epoxy resin, in the method of pouring over the item and let it drip off to make a thin coating. Craft stores sometimes carry small bottles for this kind of thing.
It isn’t so much that the plastic materials we are using are inherently unsafe for food (though some colors, fillers may be) but the more important issue will always be the porous nature of printing by layers like this, the non-smooth surface will trap bacteria and contaminants and needs to be sealed for food grade use, just like you’re thinking.
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I am not a 3d Printing expert but retired MD. Engineers might have better solutions. I am here to list safety risks.
Pure PLA, PET and ABS materials are considered food safe for injection molding though PLA is not used at all. When you want to FDM print with them, things get tricky.
IMHO PLA is a no go .
PETG is more problematic than ABS because
1- Porous nature. Lets decayed foods and bacteria seep in.
2- Layer lines make cleaning impossible. There is no way of sanding it smooth enough to make it food safe
3- Impossible to sanitize and not dish washer safe. Many dish washers work between50-70C range (I think it is 122-158F). 70C is enough to sterilize glassware as only the surface is contaminated. For 3d Printed things you even need higher temps for sterilizing. PETG known to be deformed at 70C that you might only use dishwasher Eco mode for surface cleaning. At 70C you will still not be able to sterilize but deform the pieces that it will start to let more bacteria reside in side.
3- Flexibility decrease the effectiveness of coating. There are lots of debate about the safety of coatings but let’s leave that to another day. The coating should be very though and rigid to protect. In that regards, there are several resins; we home users, can work with. But flexy nature of the object just breaks these coatings. Besides PETG is one of those materials that does not want to fuse with other chemicals. So the efficiency of coating will always be questionable.
4- Variety is insane. Clear pure PET is considered food safe but to make it PETG, manufacturers add many other chemicals and it is very hard to find Material Safety Datasheets for all brands. For the last few years, the PETG variations like Plus, Premium, Hyper Speed etc started to drop to market. Adding even more unknowns. Glow in dark, marble, wood etc is clearly no no. Only PETG you can feel safe to use is medical PETG in this regard.
5- Not all pigments are equal. The colors are generally listed (if they are at all) as pigments (not even their chemical code). Majority of the pigments are not safe according to FDA. You need to check it for every pigment yourself. If they are not listed, you need to stay away from that filament. Generally white and natural ( it does not mean clear or transparent. Chemicals are added to natural materials to avoid cloudiness and make them transparent) to are considered safe for all types of materials.
ABS shares many of the above properties but it is still considered much safer alternative to PETG because:
1- More rigid and less porous.
2- Higher heat resistance makes it true dishwasher safe. You can also dip it into hot water 80C+ (176F) and it will endure.
3-After sanding to finest surface, applying acetone smoothing makes the surface smooth enough to clean, sanitize and be safe.
4-Can not remember all but White is definitely safe but Black is toxic. If I am not mistaken pink and red are also toxic. Please recheck yourself.
5-Coating might not be needed but recommended.
Although Finished ABS products are safe, working with it is not. Fumes during printing, particles during sanding and acetone vapor during smoothing has both health and environment hazard risks. So you have to take precautions.
IMHO, 3d printing does not worth your effort and money for the items that will come in contact with your food. I only printed a few drawer organizer with White ABS. Buying a BPA free plastic ware or better glass is much easier, cheaper and safer option.
One last important note:
In order to call the product food safe, all parts of the printer that come in contact with the filament must be food safe. Especially the extruder, hotend and nozzle must be at least stainless hardened steel. If you modified them for high flow, It is highly likely they will contain brass and copper which are highly toxic. You have to revert back to original specs. I assume X series extruders are OK but i do not know If P1 series are as their extruders are plastic.
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So the best i can do is put the individually wrapped lollies/ Candies, like mentos, starbursts, sherbets etc into any bowl items i print out.as they would be protected by the paper wrapping around them.
This is another take on the subject matter…
TLDR: Don’t worry too much.
the best you can do is resin coat your 3d prints… I went at 3dprintopia this year and there was a guy that does a lot of prints multicolors such as star wars mugs, he does a lot of coffee mugs basicly and they are printed in abs so it withstands heat, then he just resin coats them couple of times with a paint brush and voila 
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The food issue is important and there have been discussions of various fibers added to filaments that can rub off easily for some. That can compound the issue if little bits come off easily.
And as long as people are thinking about safety issues, there is a whole class of dangerous prints here. I’ve reported them to Bambu a long time ago, but @MakerWorld - these are problems and are probably impacting peoples’ health.
Lots of opportunities for fibers and bits to be ground off and then burned and inhaled.
https://makerworld.com/en/search/models?keyword=Herb+grinder
Actually all the article is about printed masks during COVID period when we had shortage of, not about food containers. During that time, we too had used a lot of 3D Printed materials not limited to masks but they were either dumped to bins after one time use or send to gas sterilization department if we needed to reuse them for some reason. So the exposures of, both the microbes to the material and material to human are rather short. When it comes to household food containers exposure is almost never ending.
The sanitation methods described in the article are not inline with people’s daily practice. I hear no one using baking soda and bleach during dish washing since Covid risk ended. Thus it either adds additional choir for daily routine or skipped all together.
And his final conclusion are inline with the concerns I mentioned above and also the following is also very inline.
"The real question is, is it worth 3D printing food wares? Granted it’s fun and cool, but its more expensive and very time consuming. A plastic bowl at my local box store is 50 cents. To 3D print a bowl is 12 hours of electricity, plus $1.5 worth of filament. "
So; not so “Don’t Worry too much”.
There is no need to take any risks unless we have to face another Covid like situation.
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The parents who have toddlers think that soft and flexible things they can print and give to their child are safer and less likely to shatter like glass. Oh man how much they can be wrong.
And those herb grinders. Brilliant idea. Just sprinkle some plastic flakes on your soup. It will taste delicious.
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Yep. When I saw the first one here I wrote to the creator about plastic bits breaking off and into the, uh, “herbs” but he just brushed it off.
People don’t appreciate the dangers I think. There’s a long line of stories where people were exposed to things that ruined their heath in all sorts of horrific ways. 3D print materials in contact with food and some even smoking small amounts should scare anyone.
And there are other considerations besides chemical exposures. The morphology can also matter. Little bits coming off into food and traveling through the digestive tract can do all sorts of odd things - burrow into stomach and intestinal linings to cause reactions or who knows what? There may not be many or any studies - and this is an area where I would say “more research is needed” since so many are doing it.
And you don’t know until a link is discovered that you may have done something very foolish along the way. Even just washing car parts in gasoline to clean them - gasoline has a very large benzene component in it. It’s why gas stations in some states are required to capture fuel vapors. In high school I worked in an auto repair shop and worked on cars my own time too - lots and lots of gasoline.
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Personally I’ll never 3d print anything kitchen/food related other than maybe some storage containers or something. It’s just not worth the risk. Even if I do print something to store some spoons or whatever, I’d be coating or wrapping that thing like crazy with something known food-safe first.
From another hobby (woodworking), I was thinking shellac that’s labeled non-toxic or food safe, and maybe put a coat of food-grade wax on top of that. But maybe resin like people suggested above is better. (I know nothing about resin.) Can you coat with resin, then shellac, then wax? 
The fact that this stuff will eventually wear down to the plastic some day still makes it not such a great idea, IMO.
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You are interfering with their money bussiness, man. It’s just like youtube with fake contents for views.
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Wait until big business realises they can market “micro-plastics” as the next great supplement.
It will be in cereals, and everything else for kids and their growing bodies.
Precisely! Money over peoples’ health! Problem is those little bits of plastic will be very well hidden in the herbs. I bet most users have no clue they will be smoking all kinds of plastic bits, colorants, plasticizers, impurities, etc.
Cancer is a great weight loss drug… Cheap too if you don’t get treatment.
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No, they don’t. Just like how they didn’t realize how bad leaded fuel was until too late.
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I feel like it’s some of both. Certainly it wasn’t known that plastic (and other stuff) were going to be so unhealthy when it first showed up, so I don’t assume malice when ignorance is more likely.
But at this point in the information age, it seems there are some unethical people out there (at all levels) who don’t care that they might be hurting someone else’s health if it gets in the way of their earnings.
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Maybe make a print with the cavity designed around being able to put a Rubbermaid bowl into the cavity. You’d have the desired decorative aspect and the food grade container. You can remove that from decorative exterior and put the bowl in the dishwasher.