PLA is a bioplastic made from renewable resources like corn starch or sugarcane. It is known for being biodegradable and having a low printing temperature. It’s a staple in 3D printing, often used for creating items like kitchen utensils, food containers, or cookie cutters. However, the question "is PLA food safe?" is critical, especially for items in direct food contact. In this article, we will introduce the possible risks of using PLA as a food-grade material in both its composition and the 3D printing process. We will also explain how to mitigate these risks to answer the question: 'Is PLA food-safe?' in detail.
Recommended reading: What is PLA Filament?
Is PLA Really Food-Safe? Five Possible Risks Of 3D Printing
Food-safe materials are those materials or substances that come into direct contact with food and do not release harmful substances, contaminate food, or cause any harm to human health during use. A 1995 study showed that PLA was considered GRAS-compliant① as a food contact material, and the migration of safe substances such as lactic acid was minimal and harmless to humans. Although PLA is generally safe, 3D printed objects pose additional risks due to the printing process and material properties.
- Printing Process Residues: The 3D printing process, particularly Fused Deposition Modeling (FDM), can emit volatile organic compounds (VOCs) and ultrafine particles (UFPs). Studies show PLA emits VOCs like lactide, with emission rates ranging from 4 to 5 μg/min. These residues may remain on the surface, posing risks for "food safe 3D printing filament" if not properly managed. Research also highlights that high printing temperatures increase VOC emissions, potentially including formaldehyde or acetaldehyde, which could affect safety .
- Surface Roughness and Porosity: 3D-printed objects have layer lines, creating a porous surface that can harbor bacteria. Studies on bacterial biofilm growth show that 3D-printed surfaces, especially with micrometric features, favor bacterial attachment,. This increases the risk of contamination, as porous surfaces can trap food particles and foster microbial growth, impacting hygiene.②
- Additives and Colorants: Some PLA filaments contain additives like colorants or plasticizers not intended for food contact. While food-grade filaments are available, non-food-grade options may include harmful substances. For instance, pigments or impact modifiers might leach into food, so you need to carefully check whether the selected 3D filament is food grade 3D printer filament. Because additives can compromise safety if not FDA or EU compliant.
Adding modifiers to PLA to improve the performance of PLA is called PLA+. Recommended reading: PLA vs PLA+: Differences And Comparisons You Need To Know
- Temperature Sensitivity: PLA has a low melting point (around 110°F/43°C), making it unsuitable for hot foods or dishwasher use. High temperatures can cause deformation or chemical leaching, such as increased migration of lactic acid or degradation products, affecting "is PLA safe for food" assessments. This limits its use for applications involving heat, a significant consideration for 3D printing enthusiasts.
- Long-Term Use Risks: Prolonged food contact may lead to micro-migration, even if initial tests show safety. Studies suggest PLA might release low levels of harmful substances under acidic or oily conditions, particularly over time, raising concerns for "PLA food safe" long-term use.③
These risks highlight the complexity of "is pla food safe," especially in 3D printing, requiring additional measures to ensure safety.
Ways To Make PLA 3D-Printed items Food-Safe
To ensure that your PLA prints are safe for food contact, please follow these best practices:
- Select Certified Food-Grade PLA Filament: Start by choosing PLA filament explicitly labeled as "food grade" and certified to meet FDA CFR 21 or EU Regulation 10/2011 standards. Avoid filaments with unknown additives or colorants, as these can introduce non-food-safe chemicals.
- Prepare a Food-Safe Printer Setup: Ensure your 3D printer is clean and uses food-safe components. Replace brass nozzles, which may contain lead, with stainless steel nozzles to prevent contamination .④ Perform a cold pull to remove any residual material from the extruder, ensuring no previous non-food-safe filaments affect the print.
- Optimize Printing Conditions: Print in a well-ventilated area to minimize exposure to VOCs and UFPs, which can be emitted during the process. Consider using an enclosed printer with a HEPA filter to capture particles. Change the printing settings. Lower the temperature to cut down on VOC emissions. Use slower speeds to help layers stick better. This will reduce surface porosity (Food-grade 3D printing: Is PLA Food-Safe?).
- Post-Process for Smoothness and Safety: After printing, let the object "outgas" for at least 24-48 hours in a well-ventilated area to reduce residual chemicals. Then, sand the surface with fine-grit sandpaper (starting at 400 grit and progressing to 1000 grit) to minimize porosity and create a smoother finish, making it easier to clean and less prone to bacterial growth.
- Clean and Sanitize Regularly: Before first use, clean the printed object with lukewarm water and a mild, food-safe antibacterial detergent to remove any surface contaminants. For ongoing maintenance, sanitize with a 70% isopropyl alcohol solution or a food-safe sanitizer, ensuring no harsh chemicals are used that could degrade the PLA.
- Add surface coating: For added protection, apply a food-safe epoxy resin or polyurethane coating, such as Masterbond’s EP42HT-2FG, to seal any remaining gaps. Ensure the coating is FDA-approved and dishwasher-safe for prolonged use.
Conclusion
Although PLA is inherently food-safe, PLA filaments that have been added with additives or dyes may contain non-food-safe chemicals. In addition, PLA may also pose a food safety hazard during the 3D printing process, such as fine particles or growth of bacteria between the gaps between layers. Therefore, the use of PLA 3D prints as food contact devices requires careful management. By using certified materials, optimizing printing practices, and thorough post-processing, PLA objects can be safer for limited contact with food - although they are still not suitable for high temperature or long-term use.
Frequently Asked Questions
Q: Any PLA filament suitable for food contact?
A: No, the material of PLA suitable for food contact needs to meet food safety standards. Because some PLA filaments have other chemical ingredients such as dyes or enhancers added to them.
Q: Can I use my standard 3D printer?
A: Yes, check whether the components such as the nozzle are food safe, preferably stainless steel. In addition, pay attention to whether there are other materials left in the printer and print under good ventilation.
Q: What post-processing is recommended?
A: Clean with soap, sand for smoothness, and consider food-safe coatings.
Q: Is PLA suitable for hot foods?
A: No, it deforms at high temperatures; use for cold or room-temperature foods.
Q: Are there health risks with 3D-printed PLA?
A: If you take precautions, the risk is small, but make sure to use the right filament and post-processing measures.
Referece
①Safety assessment of polylactide (PLA) for use as a food-contact polymer
②Bacterial Biofilm Growth on 3D-Printed Materials - PMC
③Recent Advances in PLA-Based Antibacterial Food Packaging and Its Applications
④The Final Say In Food Safe 3D Printing (UVU Microbiology & Engineering