Is PLA food safe? The plastic vs the print

PLA the plastic is widely used for food packaging, but a 3D printed PLA object is not certified food-safe and should not be treated as if it were. The problem is less the polymer than everything around it: the grooves between layers that trap food and bacteria, the pigments and additives in the filament, the nozzle and extruder it passed through, and the fact that PLA cannot survive a dishwasher. Brief contact with dry food is generally considered low risk. A printed mug, chopping board or baby spoon is a different matter.

The plastic and the print are two different questions

“Food safe” is not a property of a material alone. In the UK and EU it describes a finished article, made in a controlled way, that has been shown not to transfer harmful amounts of anything into food. A cup moulded from PLA in a factory can meet that. A spool of filament printed at home has been through none of it.

So a listing that says “food-grade PLA” or “food-safe filament” is telling you, at most, about the raw material. Some manufacturers do publish a food-contact compliance statement for a particular filament and colour, and that is worth having if this matters to you. It still covers the filament, not the thing you make from it on your printer.

The four real concerns

1. Layer lines hold food and bacteria

A filament print is a stack of thin lines with tiny grooves between them, and often small gaps into the hollow interior. Food and moisture get into those grooves and washing does not reliably get them out again. A smooth moulded surface can be cleaned properly. A printed one is far harder to clean, and you cannot easily check that you have. This is the concern that applies to every printed part regardless of the plastic, and it is the main reason a print is a poor choice for anything used with food again and again.

2. The nozzle and the filament path

Standard nozzles are brass, and brass commonly contains a small amount of lead to make it easier to machine. How much of that, if any, ends up in a print is not well established, and it is likely to be very little. But it is an avoidable unknown. The same goes for the rest of the path: extruder gears, PTFE tube and a hotend that has previously printed other materials, including abrasive or filled filaments, none of which were made with food in mind.

3. Pigments and additives

Filament is not pure PLA. It contains colourants and other additives to improve printing, and PLA+, silk, matte, glow-in-the-dark and high-speed versions contain more. Manufacturers seldom say what they are. This varies by brand and by colour, and without a food-contact statement for that exact product you have no way of knowing.

4. Heat and dishwashers

PLA begins to soften at around 55 to 60 °C. A dishwasher is hotter than that, and so is a cup of tea. A PLA print put through a dishwasher will warp, and one that cannot be washed hot cannot be cleaned to the standard you would expect of kitchenware. That rules PLA out for anything that holds hot food or drink, quite apart from the other three points.

What people actually do

None of these makes a print certified food-safe. They reduce the specific risks above, and which ones you bother with depends on what you are making.

• Keep contact short and dry. Cookie cutters, cake toppers, stencils for dusting cocoa, a scoop for dry rice. Contact lasts seconds, the food is dry or is baked afterwards, and nothing sits in the grooves. This is where most people draw the line.
• Treat it as single use, or nearly. The cleaning problem only exists if you reuse the part. Use it, wash it by hand in lukewarm soapy water, dry it thoroughly, and replace it rather than keep it for years.
• Put a barrier in between. Cling film over a cookie cutter, baking paper under a stencil, a glass or a bag inside a printed holder. If the print never touches the food, most of the question goes away.
• Seal the surface. A coating fills the layer lines and gives a smooth surface that can be wiped clean. Use a coating that is itself rated for food contact, typically a food-contact epoxy resin, and follow its mixing and curing instructions exactly, because the rating depends on a full cure. The part is then only as good as the coating, and still will not take heat.
• Fit a stainless steel nozzle. It removes the brass question for a few pounds. Stainless conducts heat less well than brass, so you may need a slightly higher temperature. See hardened vs brass nozzles for how nozzle materials differ.
• Choose plain filament with a statement. Natural or simply coloured PLA from a manufacturer that publishes food-contact compliance for that product, rather than a silk, sparkle or glow blend.
• Print the tool, not the tableware. A printed part makes a good master for a mould in food-grade silicone, or a former for shaping something else. The print does the shaping and a properly rated material touches the food.

What to avoid

• Hot food and drink. Mugs, bowls for soup, anything near a kettle or hob.
• Long contact with wet, fatty or acidic food. Storage tubs, bottles, chopping boards.
• Raw meat, fish and eggs, where thorough cleaning matters most.
• Anything for babies and small children to put in their mouths.
• Anything you intend to sell or give away as food-safe. Selling food contact items brings legal responsibilities that a home print cannot meet on the strength of a filament listing.

Is PETG any better?

In two respects. PETG stays rigid to around 75 °C, so it tolerates warm water better than PLA, though it is still not dishwasher-proof in most machines. It is also more resistant to chemicals and absorbs flavours and stains less readily. The PET family of plastics is very widely used for bottles and food trays.

But every concern that comes from the printing process is unchanged: the layer lines, the nozzle, the unknown additives. A PETG print is no more certified than a PLA one. If the part needs to get warm or wet, PETG is the better of the two; it is not a way round the problem. See PLA vs PETG and PETG ranked by £/kg.

The honest answer

For a cookie cutter used a few times and washed by hand, most people are comfortable with plain PLA, and the risk is generally regarded as low. For anything that holds food or drink, is used daily, gets hot, or is for a child, buy the real thing: properly made kitchenware is cheap and tested, and a print is neither. If you are shopping for the plain PLA to make those cutters, the live list is at PLA ranked by £/kg.

Questions people ask

Is PLA food safe?

PLA as a plastic is used in food packaging, but a 3D printed PLA object is not certified food-safe. The print has layer lines that trap food and bacteria, the filament contains undisclosed pigments and additives, and it has passed through a nozzle and extruder not made for food. Brief contact with dry food is generally considered low risk, but printed PLA is a poor choice for cups, plates or anything reused with food.

Why are 3D printed parts not considered food safe?

3D printed parts are not considered food safe mainly because of their surface. A filament print is a stack of thin layers with grooves and small gaps between them, which hold food and moisture and cannot be cleaned reliably. Brass nozzles that may contain a little lead, unknown additives in the filament and the inability of PLA to survive hot washing add to the problem.

Can you put PLA prints in the dishwasher?

No, PLA prints should not go in a dishwasher. PLA starts to soften at around 55 to 60 degrees Celsius, and a dishwasher runs hotter than that, so the print will warp. PLA items that touch food have to be washed by hand in lukewarm soapy water, which is one reason they are unsuitable as everyday kitchenware.

Are 3D printed cookie cutters safe to use?

3D printed cookie cutters in plain PLA are generally regarded as low risk, because contact with the dough lasts only seconds and the biscuits are baked afterwards. Wash the cutter by hand in lukewarm soapy water, dry it well and replace it rather than keeping it for years. Covering the dough with cling film before cutting removes contact altogether.

How can I make a 3D print safer for food contact?

The usual steps are to seal the print with a coating that is itself rated for food contact, such as a food-contact epoxy resin cured exactly as instructed, to print with a stainless steel nozzle instead of brass, and to use plain filament from a maker that publishes a food-contact statement. These reduce specific risks but do not make a home print certified food-safe. Keeping contact short, dry and cool matters as much as any of them.

Is PETG more food safe than PLA?

PETG is better than PLA in two ways for food use: it stays rigid to about 75 degrees Celsius, so it copes with warm water, and it resists chemicals and staining better. The risks that come from 3D printing itself are the same for both, including layer lines that trap bacteria, the nozzle and unknown additives. A PETG print is no more certified food-safe than a PLA one.

Does a brass nozzle make 3D prints unsafe for food?

A brass nozzle is a possible but unproven source of contamination. Brass commonly contains a small amount of lead to make it easier to machine, and how much, if any, transfers to a print is not well established. Because a stainless steel nozzle costs only a few pounds, people who print items for food contact usually fit one to remove the question.