PLA and ABS vs food safety?

Is it save to print parts in PLA and/or ABS which come in contact with food.
Like a lid for a jar, a plastic spoon or lunchbox on thingiverse?

Regards,
PB

Nothing printed with a FFF printer is food safe, because there are small voids in the part (even at 100% infill) where bacteria can grow. These voids will not be cleaned out by running the object through the dishwasher either.

This is why you see almost no cups, plates, or other food items on Thingiverse. This is why making cups and plates is not a heavily publicized use 3D printers.

You can probably make a printed object food safe by buying a food grade epoxy and coating your printed object with a thick layer of this epoxy.

Edited 1 time(s). Last edit at 11/03/2012 05:38PM by crispy1.

crispy1 Wrote:
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> Nothing printed with a FFF printer is food safe,
> because there are small voids in the part (even at
> 100% infill) where bacteria can grow. These voids
> will not be cleaned out by running the object
> through the dishwasher either.
>
> This is why you see almost no cups, plates, or
> other food items on Thingiverse.

There are tons of cups on Thingiverse. I have printed some and it's not very hard to make the surfaces completely waterproof, and even if it wasn't, that's not what food safe means. (It refers to the chemical compatibility and absence of toxins)

I looked this up when I was making the chocolate extruder. I found that PLA has a food safe certification (at least for some brand) in the US, and ABS is generally unsafe (or at least I couldn't find any mentions of food safe ABS). PC can be food safe too. And, especially if you want to produce something for sale, you need to have the certification for the specific type from the manufacturer of the plastic, because the plastics are very rarely pure polymers – there are various additives...

Quote

There are tons of cups on Thingiverse. I have printed some and it's not very hard to make the surfaces completely waterproof, and even if it wasn't, that's not what food safe means. (It refers to the chemical compatibility and absence of toxins)

Waterproof does not mean there are no voids in the object.

There are 2 aspects to food safe. One of them, as you point out, is the base material non-toxic? The second aspect is what I was talking about.

If you print a PLA cup or plate, sure it is safe for use once. But then you need to throw it away because things will grow in it. And with PLA, you can't heat it up enough to steam sterilize it, because it will turn to goop.

There are food-safe grades of ABS, too. And PLA is not automatically food safe just because it is PLA - you need a certification from the supplier.

crispy1 Wrote:
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> If you print a PLA cup or plate, sure it is safe
> for use once. But then you need to throw it away
> because things will grow in it. And with PLA, you
> can't heat it up enough to steam sterilize it,
> because it will turn to goop.

What's your basis in saying that every printed object has too many voids and cavities to be safe for food use (providing that the material itself is food safe)?

Coming from an engineering workshop that makes (mostly steel) food grade equipment:

Certain materials that are used for food ARE porous or "have gaps" which can trap bacteria etc. If you're re-using the object then this is not good because (as said) the bacteria will accumulate and things will start to get festy...

Since our manufacturing process here does leave these voids (you CAN NOT 100% be certain that you don't, no matter HOW good your print looks, you can't guarantee that.

Water-tight does NOT mean it's bug/bacteria proof - a lot of parts we make are made from solid steel and need electroplating or electropolishing to be used in the food (or medical) industries.

Clay / ceramics can face a similar issue, being porous, which is why we don't buy raw clay cups for drinking from, you will find they are all painted or at least glazed with another material which IS both watertight and leaves a very smooth, shiny surface.

I'd say that using something like a pottery glaze or epoxy as mentioned above would be enough to make a FDM (printed) part acceptable for daily use as a cup / plate / fork etc.

To help convince anyone that prints are, in fact, pitted, I've got some nice pictures of some stuff from under a microscope.

This first picture is ABS, and is the top infill from a Stratasys print. The infill wasn't perfect, so those huge gouges you see are the second-from-the-top layer showing through. The scale bar at the bottom is 200 micrometers.

Image 1

This second picture is a close up of one of the above area, with the scale bar now at 100 micrometers.

Image 2

This third image is PLA, and is one of the side walls. This is a print from my RepRap. Scale is 200.

Image 3

Lastly, this is the top infill from my RepRap. Scale is 200.

Image 4

I hope that this helps convince people to seal their food prints!

PomeroyB Wrote:
-------------------------------------------------------
> To help convince anyone that prints are, in fact,
> pitted, I've got some nice pictures of some stuff
> from under a microscope.
>
> This first picture is ABS, and is the top infill
> from a Stratasys print. The infill wasn't perfect,
> so those huge gouges you see are the
> second-from-the-top layer showing through. The
> scale bar at the bottom is 200 micrometers.
>
> Image 1
>
> This second picture is a close up of one of the
> above area, with the scale bar now at 100
> micrometers.
>
> Image 2
>
> This third image is PLA, and is one of the side
> walls. This is a print from my RepRap. Scale is
> 200.
>
> Image 3
>
> Lastly, this is the top infill from my RepRap.
> Scale is 200.
>
> Image 4
>
> I hope that this helps convince people to seal
> their food prints!

Nice pictures! Have you looked at any prints after being acetone steamed or dipped? Just wondering if the slight melting of the print would help seal it more!

---

[indieflows.blogspot.com]
[www.emakershop.com]

No, I haven't. I'll do that next time I have access to the lab.

Great pics PomeroyB!

Any recommendations on a suitable low-temperature sealer for PLA? I actually use my printed shot glasses a lot

Polyurethane lacquer from Home Depot, Lowes or whichever store you buy your paint and dremel bits from. Once it's dry the surface can be considered "food safe."

Personally my ABS shot glasses work just fine as they are. Much less deadly than that cigarette I just finished off :-)

---

-Tom

This is always a fun question to see debated, but in the end the answer to the question always seems foggy for most. I think the root cause of this is the question of "Is ABS, or PLA, or " food safe can be taken in two main ways with two different answers.

1) Can I make print that is "FDA" food safe?
2) If I stick this thing in my mouth, or have food touch it then into my mouth will I die?

These will result in two very different answers. #1 is almost (I say almost because nothing is impossible) down right no. As stated above inconstant with surface finish, materials used to print the parts (hotend, heated bed, ect), and conditions the part is printed in (usually a persons desk or shop) will not meet the unnecessary standards.

#2 for this one the answer is mostly no (like stated above there are different grades of ABS and PLA so 100% can not be given). One will not be poisoned by toxins found in the plastic. Now could one get sick because of bacteria contamination yes, but this can be said for plastic cups and plates as well in which the surface has been compromised. A person is not suppose to use a cup, cutting board, plate that has been scratched for the same reason, but do people still use them of course.

This all said it is my "opinion" that it is safe to consume food that came in temporary contact with a PLA printed part as long as "good" cleaning habits are used (do not use the part in conjugation with raw foods like meat, eggs, milk, ect/ clean the part in warm water immediately before/after use with a mild anti-bacterial detergent/ seal surface with a food safe sealer/sanitize part with a non-rinse based cleaner).

Also like Tom said, there are more unhealthy actives people do in a day (use acetone in a non ventilated area, drink in access, use tobacco products, not properly bandage or clean cuts, eat left over food not heated to 160 deg F)

"Clay / ceramics can face a similar issue, being porous, which is why we don't buy raw clay cups for drinking from, you will find they are all painted or at least glazed with another material which IS both watertight and leaves a very smooth, shiny surface. "

Well, the most worrisome thing about direct use of clay-based dishes is that clay naturally absorbs heavy metals, so when in contact with any substance (water, juices, cofee, or many foods), it will allow those substances to leach off the heavy metals and redeposit them in the human body. Glazing produces a glass wrap onto the clay, thereby rendering the clay essentially chemically inert.

Not to say that pores don't play a part, which is why it's a pretty standard rule amongst those who keep house to throw away any cups, bowls etc with cracks, even when they're just through the glaze. This was brought into the limelight here in the States back in the 1970s when many were becoming sick from drinking orange juice from glazed ceramics during the hippy revolution and the number of incidents of heavy metal poisoning burgeoned and was traced back to the pottery.

Polycarb is most certainally NOT SAFE for food contact OR potable water. Nalge/Nalgene got butt-hertzed over that one in the courts and had to switch to a specific grade of food-contact/potable water-grade polyester. (I know because I was involved in the whistle-blowing.)

Look up the PBA slash endocrine-disrupter brewhaha that's ongoing, in order to fully grasp the whole situation. It's complex... and in the end if you are making an item for sale, be damn sure you are using food/water grade materials!

If in doubt, use resins like HDPE or PET. Milk-bottles and soda-bottles respectivally. If you are blessed with access to a filiment-machine (like the Lyman/Lymen Extruder on Thingverse) you can dice up some HDPE or PET and attempt to make your own filiments.

I would do it in a perfectly clean brand new extruder, any of the previous materials you've run leave residue behind. Unless you're a plastic-professional and follow a strict purging and teardown/cleaning ritual it's virtually impossible to restore a "used" Lyman to FPW-contact service.

I have attached 4 photos of ABS shot with a 50X ProScope HD (digital microscope) the lens is only 50x but still way more than you can see with magnifying glasses (about 10 times closer).

I had 2 identical pieces, one was raw out of the printer, one was acetone dipped (actually painted on). I took photos of the top and edge of the item.

The dipped one is better sealed but the surface is wavy a bit. I would not worry at all about bacteria growth as any on it would easily be removed through regular dish washing.

That being said, I myself would not eat from my ABS prints as I don't trust the chemicals in the ABS. I would however trust the PLA plastic used in printers as long as the surface could be sealed like the abs, maybe a heat gun?!?

I would never try to sell a product for food use due to laws and possible repercussions but as stated, I would put a PLA spoon in my own mouth or drink soda from a PLA cup. I would only repeat this if the surface was sealed so it could be cleaned properly.

Sniper4395 Wrote:
-------------------------------------------------------
> Polyurethane lacquer from Home Depot, Lowes or
> whichever store you buy your paint and dremel bits
> from. Once it's dry the surface can be considered
> "food safe."


Has anyone done any real testing on this? I don't mind spending an hour finishing my prints very carefully with lacquer if it means I can be really confident about food safety (especially with ABS stuff, since I'd really like to be able to steam clean or dishwash).

Something you could dip-apply like with pottery and ceramics would be really great.

Quote

Has anyone done any real testing on this? I don't mind spending an hour finishing my prints very carefully with lacquer if it means I can be really confident about food safety (especially with ABS stuff, since I'd really like to be able to steam clean or dishwash).

The grades of ABS we use get pretty soft by 100C. They might hold their shape through a dishwashing cycle, or they may not.

Also, AFAIK, unless a chemical specifically says it is food safe then you assume it isn't. So for example your typical 2 part epoxies you buy in Lowes are not considered food safe from a chemical standpoint.

My idea is how we define "Safe". Personall I think it's OK to use,but I am not sure whether we need to do some special test to sell.

... the problem defining the 'safety'-level is caused by the big amount of potential harmfull additives and 'optimizers' not listed in the receipe

---

Viktor
--------
Aufruf zum Projekt "Müll-freie Meere" - [reprap.org] -- Deutsche Facebook-Gruppe - [www.facebook.com]

Call for the project "garbage-free seas" - [reprap.org]

It sounds like the best bet is to print your prototype in plastic, tweek it, then send the tweeked .stl file to shapeways for porcelin or stainless steel printing.

VDX Wrote:
-------------------------------------------------------
> ... the problem defining the 'safety'-level is
> caused by the big amount of potential harmfull
> additives and 'optimizers' not listed in the
> receipe


Hi Guys,

PLEASE read my commentary: don't eat from unknown plastics, uncertified surfaces, and uncertified geometries. This is serious stuff. The stuff that ends up in the news about how 3d printed chinese plastic ended up giving children autism or something. That's hype from me, and not necessarily likely, but it is totally possible with unknown additives and long term exposure.

I've had filament made from a factory before. They don't want to (and don't need to) tell you every chemical in there that is dangerous because it wasn't intended for Food safety. IF you asked for food grade versions, you WOULD RECEIVE a different PLA! (and pay more). And, if not food grade, you could be picking up fragment from previous thermoplastic extrusions (i.e. nylon, abs, etc, and their unknown additives)

In fact, even if you took food safe plastic (i.e. virgin, not recycled, no additives, food-grade masterbatch color, etc), and ran it through a 3D printer, it could never received a commercial food grade rating because of the pits and valleys... i.e., it isn't a cleanable surface. And the inner surfaces (except the stainless prusa hotend) aren't food grade. Even if the surface of a print is smoothed, there is a minimum angle of smoothness defiened by the sanitation foundations (i.e. a radius of 1/4") that is required to allow mechanical cleaning (i.e. a rag with bleach) to leave no crevice unturned.

Re: solvent smoothing: Lets also not forget - eating residues of acetone vapor AND impurities from the acetone itself sedimentation inside the plastic, which you could eat.

By far the biggest concern of mine is not a few bad bacteria hiding in a corner somewhere. You have to be immunocomprimised for a few (million) bacteria or their toxins to hurt you. The real issue is the leeching of unknowns, including the catalyst that makes PLA itself, which one type is call "stannous octoate" stannous octoate safety

"Other – Stannous octoate is considered reprotoxic Category 2 (damaging to the reproductive process) based on developmental effects.21"

so yeah. its not the most dangerous thing out there, its only an additive to expoxies and paints. It is a polymerizing catalyst (not unlike a photopolymer, which by the way, you use glove to handle after prints). The rest of the MSDS reads like an MSDS for table salt (could be a sensitizer if touched or breathed as fine particles)

Sources: I've worked on developing filaments from manufacturers worldwide. I have worked on implementing national santitation foundation guidelines to commercial food dispensing equipment. Phd in bioengineering. Common sense

You only have one body, don't risk it. I don't want people getting sick and ruining the field of 3D printing for others. Some day 3D material will make it properly into the workflow of acceptable food-grade pursuits. As far as I know, (having asked shapeways) the only the 3D prints truly food safe are ceramic-glazed after printing (i.e. sealed, and smoothed, and food-grade coatings tested for ages as safe)

Edited 3 time(s). Last edit at 08/19/2013 04:43PM by Simba.

ok so it sounds like abs is more toxic than pla.

therefore, I print a pla coffee cup. Can it handle the 100 degree C coffee i put in it without going soft and leaking chemicals into my Guatamalan?

I paint it with polyurethane lacker, to seal the object against bacteria, and dry it for a month at room temp to cure it. I then put boiling coffee in that. Can the lacker withstand it without melting off into my Columbian?

thanks in advance, I want a worry free brew in my custom designed mug!

I just would not do it...

Don't use ANY plastic for food handling/storage unless you have a material certification from the vendor/supplier.

Edited 1 time(s). Last edit at 10/27/2013 08:54AM by A2.

Food safe ? Personally I would not use ANY plastic repeatedly, soft drink and water containers are actually meant to be single use. Industry campaigns very hard to convince people, and the government, to accept plastics as "food safe". You will see some reusable plastic drinking cups and plates, the drinking vessels are usually some type of styrene, the plates ? If you were to check with acceptable materials from any health department, you would be unlikely to see any plastic as acceptable, they may possibly allow some use for things that can be sterilized. Sterilizing can be done with steam, or chlorine, preferably a combination. I think the proof would be, would you allow your young child/baby to repeatedly use such an item ? I would not. I do not remember the type of plastic being used, but a lot of baby bottles were recalled due to chemicals leaching into the liquid. I guess it would be personal choice, how much is your long term health worth ? I do not play around with mine, it has already been damaged beyond repair.

Quote
crispy1

Quote

Has anyone done any real testing on this? I don't mind spending an hour finishing my prints very carefully with lacquer if it means I can be really confident about food safety (especially with ABS stuff, since I'd really like to be able to steam clean or dishwash).

The grades of ABS we use get pretty soft by 100C. They might hold their shape through a dishwashing cycle, or they may not.

Also, AFAIK, unless a chemical specifically says it is food safe then you assume it isn't. So for example your typical 2 part epoxies you buy in Lowes are not considered food safe from a chemical standpoint.

I have put several parts, both PLA and ABS, through my dishwasher. Dishwashers may vary significantly in how hot they get, but in my testing all of my ABS things were fine and all of the PLA things warped quite a bit.

I would also be very interested if anyone has found a coating or dip that can waterproof prints easily.

Sometimes I wonder if people actually understand the temperatures involved. We casually throw around things like "190 degrees C" or "100 degrees C", but I'm not sure people truly grasp how hot that actually is.

100C is boiling, and is excessive for sanitizing purposes-- Granted, more is frequently better, and if I were sterilizing a surgical implement, I'd want as much heat as possible.

Someone mentioned their coffee at 100C... I'd also like to see someone drink coffee that was 100 degrees celsius... well, actually, I wouldn't, they would instantly burn themselves very badly. According to the warning labels, 72 C (~160 F) is enough to produce second or third degree burns in about 0.5 seconds. Dropping down to a "mere" 60 C (140 F) can still cause burns in under 5 seconds.

Generally though, it's unlikely anyone's dishwasher gets to 100C. For the sanitary cycle, mine maxes out at 72C, which is going to be a bit more than PLA can handle, but under what ABS can handle (which isn't surprising, since many components inside dishwashers are made of ABS). PLA has a relatively low glass-transition temperature (60 - 65 C), so would not be a good idea (at least in my dishwasher), and no one knows what additives were used to produce the colors and/or glow effects, so I think I'd stay away from that. ABS has a much, much higher TG, but requires more effort to produce a water-tight container (and I don't have a heated build chamber).

All of this means the cup I printed out of T-Glase will probably go through the dishwasher with no problems as it's glass-transition temperature is 78C. Taulman has said it's FDA approved for direct food contact, but hasn't followed up with the certifications as far as I know, and whether that applies to the colored T-Glase, I really don't know.

Still though, there's a bit of a risk, and caution should be used. Granted, according to the rules most health and food safety experts recommend, the human race should have been wiped out millennia ago by our unsafe cooking practices (even granting that excessive antibiotic use has produced far more dangerous strains of salmonella and e. coli, but that's another discussion), but there's no sense in asking for trouble.

Quote
grat
Someone mentioned their coffee at 100C... I'd also like to see someone drink coffee that was 100 degrees celsius... well, actually, I wouldn't, they would instantly burn themselves very badly. According to the warning labels, 72 C (~160 F) is enough to produce second or third degree burns in about 0.5 seconds. Dropping down to a "mere" 60 C (140 F) can still cause burns in under 5 seconds.
.

To be fair, you're right that nobody drinks their coffee at 100C, but some coffee makers (such as one of those over-the-cup cones) operate such that near-boiling coffee is going to touch your cup (long before you drink it, hopefully).

Hey everyone! Great question - a lot of people on the Pinshape community are also asking about how to make their prints food safe so we just published a blog article on this very subject. It seems to be highly debated but there are steps you can take to make your prints more food safe. We've broken down a lot of your recommendations as well so thanks for all the comments from the community here - you helped us put this together!