About food safe 3D printing
ฝัง
- เผยแพร่เมื่อ 25 ธ.ค. 2019
- Let's talk about food safe 3D printing. I noticed on 3D printing forums, that users only ask about food safe filament type, like PLA or PETG, but some of these materials can be very toxic, depend of the coloring material or additives. It is important what type of nozzle we use, some of them contain lead. Very important task is Bacteria Buildup, gaps between layers are perfect place for them. In this video I was testing one good solution for food grade 3D printing, and that is coating with two component food grade epoxy resin. Results can be seen at the end of the video.
Download STL for the cup:
www.mytechfun.com/video/35
Szent Istvan University, Faculty of Food Science:
etk.szie.hu/
Bacterial tests are made by Department of Biotechnology and Pharmaceutical Engineering (University of Novi Sad)
www.tf.uns.ac.rs/site/index.ph...
This work was presented at 3rd International Conference on Biosystems and Food Engineering, but only abstract was published. That's why later I created this video.
www.biosysfoodeng.hu/
10:20-10:40 # Igor Gáspár, Jovana Grahovac: Food safe 3D printing
*Update (2020-06-02): I bought 3 types of antibacterial filaments too, test will be published in near future, no need to send be those filaments any more (mentioned in video) - วิทยาศาสตร์และเทคโนโลยี
![[UNCUT]”หมอปลา และทนายแก้ว” ลากไส้ขบวนการ เด็กเชื่อมจิต จ่อเอาผิดทั้งครอบครัว I คนดังนั่งเคลียร์](http://i.ytimg.com/vi/9zXrAIVBQFo/mqdefault.jpg)
Good to know. I haven't printed anything for food use, but everyone who 3D prints should know this.
Brilliant! Systematic and scientific approach to answering a question that so many of us have wondered about. Really well presented video too. Thank you
Absolutely agree. Now to find the results of future tests. I'm curious especially if the spray or painted on items to be tested later, have been already.
The most we can learn, the better.
This is awesome, finally a professional approach to this problem.
@xr7fan The problem is, that there are a lot of 3D models out there that are used in the kitchen an these are not really safe. By the way, 3D printing is not in the least about cost efficiency. Maybe you want a special cup. Your very own cup to cherish. With your name engraved.
I've always wondered whether or not bacteria truly did have a higher likelihood of growing on 3d printed parts, but I didn't have the materials/lab to do any tests. Thanks for using your resources to give us a definitive answer to this important question!
You just need a swab and a sterilized container
Thank you for the research.
Another branch to try is the SLA UV resin printing. It is supposed to be inert after curing.
I also wonder the results for SLA but I guess it's almost imposible to eliminate residual monomers from uncured resin even washed the part with IPA and postcured.
@@volkanklc9490 interesting. Thanks for the reply. Some of 3D printing channels have done light testing of other cleaning products. I wonder if there is something more effective than IPA. But for now, no 3D prints near food!
I'm researching potential 3d printing some molds for production cooking and I REALLY appreciate all of your knowledge on this topic. Even 3 years later (and many more to come I imagine), your video is helping people. Thanks so much for making it!
reading this in Sept 2023!
Thank you for doing the leg work on all of this. Science!
I’ve been doing some experiments to handle the two hard-to-address issues: microbial harbors and heat deformation (since I’m working on a coffee set). My process right now is:
1: Design so that there are no hard-to-clean spots
2: Print PLA with a steel nozzle. Finding the chemical properties of a given filament/color turns out to be hard. I’m keeping it to white Hatchbox PLA for now because white pigments tend to be pretty innocuous. I would LOVE a spreadsheet of filaments that are certified Food Safe and ones that you think are likely OK, perhaps with some that are definitely not OK so we know what to look for!
3: Thoroughly dissolve, smooth, and seal the surface with Plastruct Plastic Weld, which seems to be mostly MEK with a little bit of ABS dissolved in it.
4: Boil the piece for five minutes. This anneals the plastic really evenly. Uneven shapes and densities don’t fare as well as circular ones, of course.
One really great feature of this step is that, if you see bubbles forming on the surface before it starts to boil, you know that there is a little void in there! Mark it with a pencil for later attention.
5: Quench the piece in cold water. I don’t know why this works, but it really seems to enhance the rigidity and heat resistance.
6: Touch up where there were voids with Plastic Weld. Check by submerging again.
7: Wet sand smooth
8: Make sure Plastic Weld has a day or more to fully dry before using it, ideally by keeping it somewhere warm and dry. I don’t want MEK in my body.
What I’ve noticed so far is that coffee does not stain anywhere, while it was staining earlier in the process before I started getting as homogenous a surface as I’m getting now. That’s certainly not an indication that microbes CAN’T grow, but if there was staining then it definitely could because that would mean that coffee couldn’t get out of the voids.
I would love your thoughts on this process!
Iglidur i151 and i181 by igus are deliberatly designed to be used in the food industry and have a rating to be in permanent contact with drinking water. They may be an interesting option.
@@clockworkvanhellsing372 Interesting!
It doesn’t solve the microscopic layer fissures problem though.
@@joshuaa.c.newman7430 yes, the micro fissure issue still stands, althought the material is mold resistand. It's probably as good as it's going to get.
@@clockworkvanhellsing372 Mold resistant is certainly a step up!
I’ll check it out!
Great video. A lot of what's in this video was already suspected, but it's great to see some real science to test these hypotheses.
Awesome videos, one of the best explanatory TH-cam channels I came across! Love the scientific approach to everything. Keep the good work up ❤️
Wow, these kind of compliments are ready motivating. Thx
Great video. You covered a lot of variables that are all important to the outcome but can be inconvenient if we are looking for an easy answer.
This is a question frequently asked on the various groups I'm part of - thanks for such a comprehensive look at this! I do have to ask on the viability of SLA printed objects (however I have yet to dig into if food safe resin is avilabile so may be a moot question)
Very informative. Must see for anyone thinking in 3D printing stuff involved with food. Thanks!
Thank you for making this and helping me with my issues. I wish I saw this sooner.
I really appreciate scientific approach to this topic and your work. Thank you very much!
Thank you so much for taking the time to do the research and for sharing this great info!
Really appreciate you taking the time for this. Very well explained, w evidence!!!! Thank you
Very informative, i was always suspecting this but dont have the knowledge or equipment to test it, thank you for your work !
Nagyon jó ! Talán a PP-t szívesen láttam volna még az anyagok között, és információt az élelmiszerrel használt műanyagokról általában (gondolok itt például a mindenütt kapható műanyag merőkanálra, amit nyilván mindenki beleáztat a forró levesbe). Kíváncsian várom a szilikonos kísérleti eredményeket!
Very interesting, keep us posted on follow-ups!
I'm so excited you're working on this!! I just did some looking and found a copper antibacterial filament called Copper3D which has been shown to decrease bacterial growth over time. If I order some for my application, I will definitely send you a cup to test. This work is so important, please keep going! ^_^
I already tested antibacterial filaments (copper3d too), one of my latest video
Nice video, I wonder how transforming Resin printed (photon/mars/epax) parts into food grade would work.
Very interesting! I work on food industry for almost 13 years now and I0m looking forward for 3d printing o penetrate this industry woth efectively food safe materials and solutions with minor need of post processing! Looking forward for more videos on research an solutions to fix this kind of problem!
I am very much interested to see where this goes, particularly about the type of food grade epoxy resin. I have seen some brands in the US - artresign that is food certified but I have never used it. Thanks for doing this!
The problem is eventually the food grade epoxy would wear off. That's my concern with it.
Excellent video! Was looking for this guidance for a while!
Thanks for the thorough research!
Awesome video -- thank you very much for your hard work!
Szuper Videó! Köszönöm az infókat!
Great video on a very interesting topic I've always wondered about. Thank you!
Fantastic work, Greatly appreciated!
Very useful, thank you very much Igor!
Great work, other thoughts I've had on food safe 3d printing, dipping prints in a thinned polyurethane varnish like 'wipe on poly' and it would be interesting to see how soaking a used part in a sterilising solution like hydrogen peroxide would affect the amount of bacterial growth.
Fantastic Help!
Great video and impressive slides!
Brilliant content! Thanks
Excellent video and well explained, I'd like to see how the antibacterial filament works out when you get around to that
I bought 3 type of antibacterial filaments. Test probes are already in labs, only I am waiting for results (labs were closed due covid19 situation)
Thank you very much for your work. I'm really curious to see the results of the use of food safe varnish and polyurethane spray. Hope to find the next video soon :)
Next video in this topics will be testing antibacterial filaments (3 types). Everything is prepared, but currently we are not allowed to go into laboratories, university buildings are closed, because of this current covid situation.
Very good video, lots of very useful detail.
I have a very specific question however: What of a TPU printed mouth guard, kept submerged in isopropyl alcohol when not in use? From a toxicity standpoint, I have heard that TPU is completely inert, albeit I have not looked into the additives. I am aware that TPU is Hygroscopic, but a combination of the drying effects of alcohol and the disposable nature of 3D printed objects makes it seem almost an acceptable flaw, if only due to being easily circumvented.
Your point regarding silicone molding may also be valuable in this situation. Due to the low temperature resistance of PLA, a positive mold could be made of the teeth, which can then be transferred to a negative, and then transferred again into silicone.
Thanks for this cool study!
Very professional , thank you !
Amazing! Thank you for such rich information!
This info is gold, thanks for sharing
Köszönöm szépen!
Thank you Igor, it was a very big help to my research!
Glad to help. What kind of research, if not a secret?
I have had good luck flowing cyanoacrylate glue ( super glue) to smooth and strengthen parts. This glue is also used to closed wounds. Have you tested it as a food safe coating?
Normally listening to 2x I actually had to put this on normal speed to understand, great content! Following and subscribing
:) I agree. I don't think there was a single unimportant word in the entire presentation.
have you looked into high temp 3d printing like that of "vision miner" ? it may defeat the monetary argument for 3d printing but would be interesting to see if it could work. also it could open up the use of a steam sanitiser like that in the restaurant industry due to its heat resistance.
Very interesting. Keep on the good work
Annealing isn't actually such a bad option. I printed a small cup with 35% infill and placed it in the oven at 70C for ~1h. Then it could resist the dishwashing cycle several times with no noticeable issues. I'm still worried about the surface finish and the fact that water (from washing) might be trapped inside the comb structure inside, no way to check for that, except by weight perhaps.
I bought food-grade epoxy to coat an identical cup and I got the mixture wrong, it never hardened properly, remaining slightly sticky. So that's another parameter to worry about.
Thanks for sharing your experience!
Great video. Thanks a lot.
Regarding making 3D-prints food-safe: there are food-safe resins for resin-based 3d-printers (SLA). and there is a lesser known way to treat FDM-based prints with such a resin to smoothen in. in other words, the FDM-print gets sealed in the resin. Still, I wouldn't go for a long term usage.
My own 3D-prints that I use with food are usually just clips for bags with an additional screw that allows to fill rice, beans etc from a bag into another container. I wouldn't let it get wet.
By the way, there is always the option to let it soak in alcohol and desinfect itself with UV-light.
"there are food-safe resins for resin-based 3d-printers"
can you name a few? or are you just referring to dental grade materials?
Exactly. As an engineer in materials,medical and areospace myself, one thi g that is never ever mentioned in any videos about if 3d printed parts are food safe.... the mere fact that if they are sterilized with an agent that has LOW surface tension such as rubbing alcohol. Ipa surface tension is about 21 dynes/cm vs water at about 73 dynes/cm. The low surface tension of rubbing alcohol allows it to get into the dimples, cracks, etc and sanitize it. In fact, ipa can get into spaces smaller than viruses, this ia why it is used in facilities that manufacture filter that filter out viruses from the blood. This ia why bleach water has a hard time with 3d printed parts. Its surface tension is the same as water. However, hot soapy water has about 25 to 30 dynes/cm as well. The soap helps break up that tension.
@@LT72884 That's so interesting - total layman here and never would have considered the surface tension of fluids limiting their abilities like that. Thanks for the insight!
Excellent ! Thank you
I work for a special education facility that is seeking to train students on the autism spectrum for vocations in both the food industry and in the additive manufacturing industry. We would like to find ways to safely integrate these two programs. Your two videos are the most comprehensive look at the problems inherent is using 3D printed parts in a food environment. Thank you so much for that.
Aside from the food safety issues, one of the issues that we are trying to fully understand regarding anti-microbial filaments is the relationship between time and efficacy. For instance, if we use an anti-microbial filament for a frequently touched surface, what might be 'safe' intervals between being touched by one student and then another? It seems that there are a LOT of unanswered questions that must be addressed if we are to develope 'best practices' using Cicla3D, Copper3D, XYZprinting or other anti-microbial filaments that come along. But, it is definitely worth pursuing.
Thank you for moving us well along that path.
Thank you so much for taking the time to research and share your information! There seems to be many websites trying provide guides on how to make 3D prints food safe, however their credibility is questionable.
Do you think heat smoothing PETG would provide a food safe seal?
I made a coffee bean funnel, would you consider something like this "low" or "high" risk? I have been sealing with 2 part epoxy (FDA approved) however I wonder if it is overkill.
Thanks again!
I am not sure about heat smoothing PETG, I don't have those experiments. I only tried smoothing PolySmooth filament with isopropyl alcohol, it give better (but not perfect) results. th-cam.com/video/DcWiA-sqPnI/w-d-xo.html . Coffee bean funnel, if it is dry, not hi-temp, then I would say "low" risk. And if it is coated with epoxy, for me that's "no risk" (with FDA Epoxy as you mentioned)
I am loving your video topics
Hi great video thank you so much!! quick question PLA + EPOXY food safe still safe ?
Hi, thanks a lot for posting this video. Very helpful. Great approach, I wish you had more views.
Thanks. I wish that too, but TH-cam has weird algorithms nowadays.
Great work! Continue please
I will have few more tests in this topics, only I have to wait our labs to open again (after covid 19 break). I am waiting results from testing antibacterial filaments and also testing silicone molds created from 3D printed casts.
This is fantastic. The most thorough explanation and research of food grade 3d that I've seen. I didn't expect to have the plastic add-on components and metal contamination covered. One thought, though, along the lines of resistance to bacterial growth. While the test done on water rinse was scientifically accurate and suitable for mass produced parts, I don't know that it is representative of a home user who will rinse the objects with soap and water and dry. I also don't know how much the texture of a 3D printed part compares to other non-plastic textured materials, such as brushed stainless steel or wood. Commercial kitchens don't use those surfaces much, but home users do, and they are generally considered safe. You absolutely proved, though, that the texture and potentially voids of 3d printing ARE an issue. This is great info.
Personally, I would be hesitant to use epoxy coated parts because I know that epoxy will gradually wear off and enter the food, and to me the risk of additional toxic chemical contamination (cancer risk) is higher than bacterial compromise. I know the plastic itself will do that, but it's one more layer of chemical that I don't perceive a need for. I also would be hesitant to use bio-resistant filaments, because I don't want to ingest the ions. I don't know how the rate of exposure would work, because the ions are very likely to leach out at greatly different rates depending on use - ice cube tray with water, compared to hot tea (acidic). But all in all, this is fantastic information. Thank you!!
As an engineer in materials,medical and areospace myself, one thi g that is never ever mentioned in any videos about if 3d printed parts are food safe.... the mere fact that if they are sterilized with an agent that has LOW surface tension such as rubbing alcohol. Ipa surface tension is about 21 dynes/cm vs water at about 73 dynes/cm. The low surface tension of rubbing alcohol allows it to get into the dimples, cracks, etc and sanitize it. In fact, ipa can get into spaces smaller than viruses, this ia why it is used in facilities that manufacture filter that filter out viruses from the blood. This ia why bleach water has a hard time with 3d printed parts. Its surface tension is the same as water. However, hot soapy water has about 25 to 30 dynes/cm as well. The soap helps break up that tension.
@@LT72884 this video doesn't state if they used soap, also like you said alcohol can get in small places, would like to know if they could run the tests again with cleaning it with this, also note the temps of the liquid used. as even a small bit of heat i am sure can kill some viruses.
@@yodasuki luckily, my internship for my medical and aerospace degree, i repeated this experiment. I cultured 10 very dangerous pathogens, and soapy water cleans just fine, and so does alcohol. Right now im redoing the entire project to test other ideas haha
So just curious by "under the tap" do you mean washed with soap? or just water? if soap was used was it anti-bacterial? Love some proper science!!
Look forward to more vids!
I'm not sure if normal "food safe" materials would be bacteria free if they weren't washed with soap. I'd like to see some controls in these tests.
It's great to see these sorts of technical videos about 3D printing.
Thank you *My Tech Fun.*
Even if they weren't, and that was added, there would still be bacterial growth, because water can not penetrate the smallest of the nooks and crannies due to it's viscosity.
@@Spartacusse and thats why you add soap.. from the way he talked about it they just used water. also you can use water and alcohol and then clean with soap.. make sure its warm.. I;d like to know if that would help
Very interesting information.
Very informative, thanks.
Thanks for the info
thank you for this great work !
I have a question, in this particular experience you checked the small cups.
what if the food we put inside these cups is cooked in the oven, is it safe to eat ?
Depend, but something like Cookie cutters, yes, it should be OK. But try to clean the cutters as much as possible.
Thank you for your answer!
Üdv Igor. Szuper lett a videó :) Profi magyarázat
Köszi
Excellent info!
Great video! What about using PP (polypropylene) ? There are food-safe PP filaments and you can just put it in a dishwasher (after each use). Shouldn't that be one of the best options?
PP is used commonly in injection molding, but it is hard for 3D printing, won't stick to bed.
Thankyou for the fantastic video, how about 3d printing a mould and casting silicone ? I think silicone can be washed at high temps?
That's exactly what I am working on now. Earlier on our department we created some silicone casts for chocolate (only not from 3d printed objects). But it is important to use silicone with food safe certificate. There are a lot of different types.
@@MyTechFun oh thats brilliant yes thankyou for doing all of this work I look forward to seeing your future videos, its people like you that make the internet such a nice place! :D
@@MyTechFun will there be a problem with a silicone? e.g., can the silicone have traces of lead?
Thank you!
Love it!
Is there a follow up to this video? Thanks!
Yes, I tested polysmooth and some antibacterial filaments.. and soon nonoilen, it can be cleaned at 110C
@@MyTechFun Great! Looking forward to watching.
did you try acetone vapor smoothing some prints? should get the surface completely smooth.
That works with ABS only, but ABS cannot be used with food
@@MyTechFun d'oh! right!
very nice, ty fot your work!
Thank you, this video is very helpful!
Thank you!!!
Brilliant! Thanks a lot for sharing your evaluations)
Im thinking about making chocolate molds of silicon by using 3d model as a shape!
Very interesting. As you're doing some legitimate studies into the food safe properties of different filaments, I'd contact the manufacturers of the more exotic filaments to request samples for testing. I'm sure many of them would be happy to oblige, especially if they believe their products to be safe for this kind of use or simply want confirmation one way or the other.
I contacted two companies so far, but they are not interested, I am "nobody" with less than 200 subs. I added my workplace address in description if anybody wants to send me few meters of antibacterial filaments. Cups needs approximately 1m filament, but I would like to print 3pcs for better statistics.
That's a shame. Well, count one more towards your subs. :)
@@MyTechFun Another sub for you. Great video and thanks for making it.
@@MyTechFun Hi Igor, Im from Polymaker and although subs number could be a criteria of selection for specific marketing partnership, we are also very interested in project which could benefit the 3d printing community and bring the industry forward, Im very happy to collaborate and help you in your testing. I just emailed you and hope to be able to start a collaboration together.
Thanks.
Oh, what about SLA printer?
3d print model and using thermoforming to make the mold, I think it can work as food safe
Yes, where possible. I am just working on similar project. I will post my results in 1-2 months.
Great Video
Good test
Thanks for sharing:-)
I've heard some 3d artisans use acetone to smooth their finished products? Would that seal the gaps and prevent bacteria from moving in and setting up shop?
With Acetone you can smooth ABS or ASA, but they can't get FDA certificate, not even in nature version.
Fantastic video. How safe are food safe epoxies? I would worry if you don’t get the proportions 100% then you will still end up with volatile compounds. I also wonder about resin prints. If they can make food safe epoxy, surely they can make food safe resins?
You should have a look at Colorfabb HT. As far as I know they are FDA approved, and it can withstand temperatures up to 100celcius. So it can easily be washed in machine. This is what I have used, and always was my things in washing machine at high temperature.
ht.colorfabb.com/what/ colorfabb.com/ht-clear
@@oleost In near future I will testing cleaning methods like: hi-temp in washing machine (with similar filaments you mentioned), sterilization in micro wave (we do this at home for our baby bottle, plate..) , ultrasonic cleaning, using antibacterial soap before using the 3D printed object (in this video there is a time interval between cleaning under the tap and antibacterial testing, because this is simulation of using in kitchen.
Don't underestimate how long trace amounts of some poisonous thermoplastic can reside inside the melting zone.
You should just replace the throat and the nozzle.
Also smoothing does nothing to pores.
It still remains porous.
So just coat it.
You can put it in a pressure pot, to fill the porus with epoxy... Can't you?
@@geeklany why not just coat it with epoxy?
Also you can't
@@goury what can't I? If you put it in a pressure pot, the epoxy is going to fill the pores. It's a known way to stabilize porous Wood for example. You can also stabilize bread with it, and turn it. Peter Brown did a video about it, it's fun (should not be eaten... It's a gag 🤗)
Pores on surface will be covered by epoxy. That's enough for food safe. If you want to cover pores deeper, add some acetone to epoxy (see xtc-3d epoxy tutorial). With this you can improve strength.
For the bacteria can you use uv during the print
Will that keep it from growing bacteria from repeated use?
Are certain beds considered not food safe? I currently have a PEI on my Ender 3 S1 Pro. Thank you
PEI is teflon coating. You probably have a teflon coated baking dish too in kitchen.
Please, is this research viable during this COVID situation for printing antibacterial respirator valves?
Are these only reasons bellow why SLS PA12 valve is confirmed safe for medicine use unlike FDM ones:
1. Superior SLS printed surface unlike FDM layerlines (prone to virus/bacteria growth)?
2. PA12 more advanced thermal and chemical properties (offer successful sterilization and disinfection)?
In this research we were testing only effect of bacteria (and yeast). The virus reportedly survives for over 48 hours on the plastics (or even 90 hours, according to some other studies). Yes, both reasons, SLA surface is smooth and can be thermal sterilizated. One of possible solution (instead sterilisation) is using the antibacterial filaments (which tests are in progress currently, but again only for bacteria and yeast). Coating with Epoxy can raise the thermal properties (Epoxy term.res. is up to 150°C, but layer of exoxy is thin), I don't have exact numbers, I think still not for sterilization. Anealing of plastic can raise this thermal resistance, but problem is that object deformates significantly (with valves you need precision). One of the solutions we are also working on is sterilisation with ultra sound. First experiments shows promissing results, but this research is still in progress (it is hard to progress, education is moved online here in Hungary, aproach to our laboratories is limited). Regards, Igor
@@MyTechFun Btw, i am speaking of (powder based SLS, not resin based SLA). Italian company printed SLS parts only because of freedom of geometry that technology offers unlike FDM and SLA. And wasn't sure if its printed only because of geometry and PA12 material? Because i am trying to get successfull results with more affordable technologies available on everyones desktop (FDM and resin SLA).
Again thanks a lot for deep answer, your previous and future effort !!!!
Were the cups washed with soap or just rinsed as the video shows?
In this test just under the tap. There is another similar test, using a dish soap too
It might be possible to find a biodegradable filament which is food safe, which would limit the impact of 3D printing surface. Certainly not for the same use cases, but could be an easier path to start with?
Few weeks ago I tested antibacterial filaments too. Interesting results (and most of them have FDM certificate)
Nice video,
But what about food safety from a migration standpoint? Would be material be able to comply with EC No 10/2011?
Nylon 6/6 coated in epoxy and polycarbonate. Both require a much higher printing temperature and are less forgiving to print. UHMWPE possibly?
I just hope, as was shown at the top of the video, that people aren’t taking “food grade” at face value. There are a lot of people who will do so, not see this video, not question it and think they’re off to making kitchen and pet food accessories, where they come into close and semi-permanent contact with food and it won’t turn out well.
copper/brass is antibacterian, why we can't use it for food? very reactive with acid?
Generally food safe is good for aquariums. Curious if the materials would be good for aquarium use even with bacteria propagation as often you want bacteria growth to process fish waste.. I understand petg is quite good. I also know some additives aren’t great as they could leach. Having said that I did a custom diy background with cement. This tank was made and cured for about 2months and flushed repeatedly. I have had no fish die from that.
So thoughts on materials for fish tank usage?
Thoughts?
Oh wow didn't know there were brass and stell alloys with lead in it :O
Can I use ABS FOR CHOCOLATE? I won’t be putting it in harsh heating elements. Just pouring for the mold shape.
ABS is not recommended to have direct contact with food.
what you can tell about PSU filaments material? I heard that's truly food-safe, but I don't know if its still safe in an common 3d printer
PSU filament needs very high printing temperatures (360°C), full metal extruder, 150°C bed.. Bacteria would grow up in these pores too after some time, but big advance is that it is very temperature resistant, it can be washed on high temperatures or sterilized in microwave like I described here for few seconds: th-cam.com/video/fFOc6d4Ry9M/w-d-xo.html
can you rerun the bacteria experiments for dry foods such as whey protein powder?
I am happy to see the collaboration with Novi Sad. Sanding could also help to get a smoother surface. Great explanation :) Greetings from Serbia!
I work a lot with University in Novi Sad. Sanding, you mean sandpaper? (peskarenje ili šmirglanje)? Pozdrav iz Budimpešte.
You also get FDA approved ABS filament.
Hm. ABS as base material cannot be used in food safety applications. That must be some very modified material. Link or brand please?
You could buy a basic metal cup/container and then print a detachable decorative cover for it and coat it with something. This way food or your lips (if you drink from it) would never get in touch with the printed materials.
Nickel coated copper nozzles should in theory be another food-safe option