One of the selling points used by several filament brands is that their PLA filaments are “food safe.” From this, it could be easy to assume that it’s excellent to print a plate and be safe to eat from because it’s food safe. It’s unfortunately not quite that easy. However, the reality is that you’ll need to take further precautions.
For filaments, this is the spool of filament. Food safety typically indicates that all of the materials in a product are safe to contact food. It’s important to remember, though, that your 3D printer has likely used non-food-safe filaments in the past.
While you don’t have to worry about a large-scale build-up of old material, you’ll still always have trace remnants of non-food safe filaments. If you do take great care to properly clean your printer, it’s also important to ensure that the hot end doesn’t contain toxic chemicals itself. A stainless-steel nozzle, for example, is a safe option.
One of the things to consider is that even if the filament itself is food safe, additives may not be. For colored filaments, this can be the dye. Still, it can also be additives used to make the filament easier to print.
Bacterial Breeding Grounds
Even if you have a filament that is actually food safe and have taken care to ensure your setup is safe, there is still a fundamental problem. 3D printed materials are generally porous to some degree. The primary issue is the layer lines, which form ideal hiding places for bacteria to grow.
You also have the risk of smaller gaps that may be almost impossible to see that can let germs deeper into your print. One way around this is to only use a print for food once, or in the short term if it’s only used for water.
Another possible solution is post-processing. You can make a more long-term food-safe product by using a smoothing process and then applying a food-safe coating. You should be aware of the limitations of the food-safe coating you use, though, and those of the PLA.
For example, PLA is fine with low temperatures. Still, with a relatively low glass transition temperature, it generally can’t survive through a dishwasher. Additionally, your food safe coatings may not survive cleaning with hot water or a scouring pad.
Unfortunately, the evidence suggests that PLA is not safe for use as kitchenware. Have you got any tips for making PLA prints food safe? Let us know down below.