Category Archives: safety

3d, safety, Uncategorized

Making Your 3D Prints Mouth-Safe and Food-Friendly: What You Need to Know

Leave a comment

When I printed my first double-chambered flute on my 3D printer, I was thrilled to see it come to life. But as I prepared to play it, a question nagged at me: Is it actually safe to put this in my mouth? That one query opened a whole new world of research into the safety of 3D printed objects—especially those that come into contact with food or the human body.

Me with my new 3d printed double flute

(who am I kidding – this is made of PLA and I did blow into it before even considering all of this.)

3D printing offers incredible possibilities—from custom cookie cutters to personalized water bottle lids and musical instruments. But just because something can be printed doesn’t mean it should be used without considering safety, especially for anything that goes near your mouth or food.

Understanding Food Safety Terms

Before diving deeper, let’s get a handle on a few critical terms:

  • Food grade: A material is safe for human consumption or is allowed to come into contact with food.

  • Food safe: A food grade material that meets safety requirements for its intended use and won’t pose a health risk.

  • Food contact surfaces: These are surfaces that touch food or your mouth and must be nontoxic, durable, and easy to clean.

These terms aren’t just relevant for kitchen utensils—they’re also important for things like wind instrument mouthpieces that see prolonged contact with your lips. The underlying concern is migration—the transfer of small particles from the printed object into food or the body.

Why Basic 3D Prints Aren’t Safe (Even with “Food Safe” Filament)

Here’s the truth: even if your filament is labeled “food safe” or “food grade,” that doesn’t make your printed object safe by default.

  • Fused Filament Fabrication (FFF) creates objects with microscopic crevices between layers—perfect hiding spots for bacteria and mold.

  • These gaps are hard to clean, even with a dishwasher (if the material can tolerate high temperatures).

  • Studies show that untreated 3D prints can harbor significantly more bacteria than coated or properly treated ones.

This is especially problematic for items with repeated or long-term contact, like flutes or cup rims.

Material Considerations: Not All Filaments Are Created Equal

Some materials are potentially safer than others:

  • PLA, PETG, and PP (polypropylene) are commonly considered food-safe options—but only under certain conditions.

  • ABS and ASA? Not safe for food contact.

  • Filament colorants and additives matter too. Even if a base polymer is safe, pigments or other ingredients might not be. Always check with the manufacturer.

For commercial or high-stakes use, look for certified materials—like those compliant with FDA CFR 21 (U.S.) or EU 10/2011. Just be aware: “compliant with” is not the same as certified or approved.

The Printer Itself Can Be a Source of Contamination

Even if you’re using the right filament, your printer might not be clean enough for safe food contact.

  • Replace brass nozzles with stainless steel—brass can contain lead.

  • Avoid cross-contamination from previous filaments or lubricants.

  • Keep your printer—inside and out—as clean as possible.

Why Cleaning my Flute isn’t Good Enough

  1. Layer Lines = Micro-Crevices

    • FDM/FFF 3D prints, including PLA, have tiny ridges and gaps between layers.

    • These crevices trap saliva, moisture, and bacteria, which can’t be fully removed—even with scrubbing, soap, or alcohol.

  2. Biofilm Formation

    • Bacteria can form biofilms—slimy protective layers—that resist even harsh cleaners.

    • Over time, this can lead to odors, staining, or health hazards.

  3. Porosity Makes Sterilization Difficult

    • Unlike glass or stainless steel, PLA is porous.

    • That means typical cleaning doesn’t penetrate deep enough to sanitize completely.

  4. Heat-Based Cleaning = PLA Deformation

    • PLA softens at ~60°C (140°F), so it’s not dishwasher-safe or steam-sterilizable.

    • Autoclaves, boiling, or hot water will warp or weaken your print.

What About Specialty Cleaning Methods?

  • Isopropyl alcohol or diluted bleach may reduce surface bacteria, but again, they can’t reach deep into the layer gaps.

  • UV light (like toothbrush sanitizers) may help somewhat, but only on exposed surfaces, not inside layer lines.

  • Long-term, repeated cleaning degrades PLA, especially if it’s soft or has fine details.

The Essential Step: Surface Coating (Sealing)

Because of the porous nature of FFF prints, sealing the surface is key to making your item mouth-safe or food-friendly.

  • Use clear, food-grade epoxy resins or polyurethane coatings that are explicitly labeled food safe.

    • Popular choices: ArtResin (compliant with FDA CFR 175.300), MasterBond EP42HT-2FG.

  • Avoid coatings that are only labeled “non-toxic” (like Mod Podge or Krylon sprays) unless they specifically state food safety.

  • Be cautious—liquid resins are toxic before curing. Use gloves, a respirator, and follow all curing instructions carefully.

    • An improperly cured resin can leave your item dangerously unsafe.

Limitations of Coated Prints

Even the best coating isn’t magic. Your sealed object won’t be as durable as a ceramic plate or stainless steel fork.

  • Most coatings aren’t heat-resistant—don’t microwave or wash in hot water.

  • Scratches or wear can expose the porous print beneath, allowing bacteria to creep in.

  • Not ideal for cutting boards, utensils, or anything subject to frequent abrasion.

Considering Alternatives and Safer Workarounds

If sealing sounds too risky or complicated, consider other options:

  • Use food-safe sealants like water-based poly coats (with proper research and testing).

  • Make molds using your 3D print and cast with a food-safe silicone or material instead.

  • Be cautious with SLA (resin) printing. Even when coated, most resins remain inherently toxic and prone to wear.

Final Thoughts: Is It Worth It?

Yes—but only if you do it right.

Creating food- or mouth-contact 3D prints is totally possible. But it requires more than just buying “food-safe” filament. It’s about:

  • Choosing the right material (and checking additives)

  • Keeping your printer clean and lead-free

  • Applying a properly cured, food-grade coating to seal your print

And even then—understand the limitations. These prints won’t last forever and must be treated with care. For commercial products, certification and compliance are non-negotiable.

When in doubt, always check the documentation, contact manufacturers, and—above all—prioritize safety.