The short answer is no, 3D printed PLA is not food grade. There are several reasons why 3D printed PLA is not suitable for direct contact with food or beverages, such as the risk of bacterial growth, chemical leaching, and degradation. In this article, we will explain these factors in detail and provide some alternatives and precautions for using 3D printed PLA for food-related purposes.
PLA stands for polylactic acid, a biodegradable and compostable thermoplastic derived from renewable resources such as corn starch, sugarcane, or cassava. PLA is one of the most popular materials for 3D printing, as it is easy to print, has a low melting point, and produces a smooth surface finish.
3D printing is a process of creating a three-dimensional object by depositing layers of material on top of each other, following a digital model. There are different types of 3D printing technologies, such as fused deposition modeling (FDM), stereolithography (SLA), and selective laser sintering (SLS), but the most common one for PLA is FDM. FDM involves heating a filament of PLA and extruding it through a nozzle, which moves along the X, Y, and Z axes to create the desired shape.
Why is 3D Printed PLA Not Food Grade?
There are three main reasons why 3D printed PLA is not food grade: bacterial growth, chemical leaching, and degradation.
Bacterial Growth
One of the biggest concerns with 3D printed PLA is the risk of bacterial growth. This is because 3D printed objects have microscopic gaps and crevices between the layers, which can trap food particles and moisture, creating a breeding ground for bacteria and fungi. These microorganisms can cause food poisoning, infections, and other health problems if ingested.
Moreover, 3D printed PLA is not dishwasher safe, as the high temperature and pressure can warp, crack, or melt the object, making it even more prone to bacterial contamination. Therefore, 3D printed PLA should not be used for storing or serving food or beverages, especially hot, acidic, or moist ones.
Another issue with 3D printed PLA is the possibility of chemical leaching. This means that some of the substances in the PLA or the 3D printing process can leach into the food or beverage, altering its taste, color, or safety. Some of these substances include:
Residual monomers: PLA is made from polymerizing lactic acid, a natural and harmless substance. However, some of the lactic acid molecules may not be fully polymerized, resulting in residual monomers that can leach out of the PLA. These monomers can cause irritation, inflammation, or allergic reactions in some people.
Additives: PLA often contains additives such as colorants, stabilizers, plasticizers, or fillers to improve its properties or appearance. Some of these additives may not be food grade or may not be compatible with the PLA, causing them to leach out of the PLA. These additives can have various effects on the food or beverage, such as changing its flavor, odor, or pH, or introducing toxic or carcinogenic compounds.
Printing parameters: The 3D printing process involves heating the PLA to high temperatures, which can cause thermal degradation or oxidation of the PLA or its additives. This can result in the formation of volatile organic compounds (VOCs), such as acetaldehyde, formaldehyde, or lactide, which can evaporate or leach into the food or beverage. These VOCs can have negative impacts on the food or beverage, such as reducing its shelf life, nutritional value, or sensory quality, or posing health risks such as respiratory irritation, nausea, or headaches.
Degradation
The third reason why 3D printed PLA is not food grade is the risk of degradation. PLA is a biodegradable material, which means that it can be broken down by biological agents such as bacteria, fungi, or enzymes. This can be beneficial for the environment, as it reduces the amount of plastic waste, but it can also be detrimental for the food or beverage, as it can affect its quality, safety, or appearance.
Degradation of PLA can occur due to various factors, such as temperature, humidity, pH, oxygen, light, or mechanical stress. Degradation can cause changes in the PLA, such as discoloration, brittleness, cracking, or loss of strength. These changes can compromise the integrity and functionality of the 3D printed object, making it unsuitable for food or beverage contact.
What are the Alternatives and Precautions for Using 3D Printed PLA for Food-Related Purposes?
Despite the risks and limitations of 3D printed PLA, there may be some situations where it can be used for food-related purposes, such as for decorative, educational, or experimental purposes. However, some precautions and alternatives should be considered to minimize the potential harm.
Use food grade PLA: Some PLA filaments are specifically designed for food contact, as they are made from certified food grade materials, have no additives, and undergo rigorous testing and quality control. These PLA filaments can reduce the risk of chemical leaching, but they still have the issues of bacterial growth and degradation. Therefore, they should be used with caution and only for short-term or one-time use.
Use a food safe coating: Another option is to apply a food safe coating or sealant on the 3D printed PLA object, such as epoxy resin, polyurethane, or silicone. These coatings can create a smooth and impermeable layer on the surface of the PLA, preventing the entry of bacteria, moisture, or chemicals. However, these coatings may also have their own drawbacks, such as altering the appearance, texture, or flexibility of the PLA, or requiring special equipment or skills to apply.
Use a food safe barrier: A simpler and cheaper alternative is to use a food safe barrier between the 3D printed PLA object and the food or beverage, such as a plastic wrap, a ziplock bag, or a disposable cup. These barriers can isolate the PLA from the food or beverage, avoiding direct contact and contamination. However, these barriers may also have some disadvantages, such as reducing the aesthetic appeal, functionality, or durability of the PLA, or generating more plastic waste.
Use a different material: The best option is to use a different material that is more suitable for food contact, such as stainless steel, glass, ceramic, or wood. These materials are more resistant to bacterial growth, chemical leaching, and degradation, and are more durable, hygienic, and easy to clean. However, these materials may also have some challenges, such as being more expensive, heavier, harder to print, or requiring post-processing.
3D printed PLA is not food grade, as it poses several risks and challenges for food or beverage contact, such as bacterial growth, chemical leaching, and degradation. These factors can affect the quality, safety, or appearance of the food or beverage, and cause health problems or environmental issues. Therefore, 3D printed PLA should not be used for storing or serving food or beverages, especially hot, acidic, or moist ones.
However, there may be some cases where 3D printed PLA can be used for food-related purposes, such as for decorative, educational, or experimental purposes. In these cases, some precautions and alternatives should be considered, such as using food grade PLA, applying a food safe coating, using a food safe barrier, or using a different material. These options can reduce the potential harm of 3D printed PLA, but they still have their own limitations and trade-offs. Therefore, they should be used with caution and only for short-term or one-time use.
3D printing is a fascinating and innovative technology that can create amazing and unique objects, but it also has its drawbacks and challenges. When it comes to food or beverage contact, 3D printed PLA is not the best choice, as it is not food grade. However, with some careful planning and research, it may be possible to use 3D printed PLA for food-related purposes, as long as the risks are minimized and the alternatives are explored.
