Food safety and epoxy resin: A common concern among craftspeople

Epoxy resin is a versatile and attractive material for various applications, including Do-It-Yourself crafts and resin art. Not long ago artists came up with a creative technique of applying the resin in unique patterns over surfaces that can go in direct contact with food.  Indeed, charcuterie boards, live edge cutting boards and resin art projects like ocean waves on wooden boards have become very popular in recent years and are often designed not only for decorative purposes but to be functional pieces. 

Not surprisingly, there is one question we receive at Nerpa Polymers that is by far the most frequently asked: “Is Nerpa epoxy resin food-safe?”

Navigating the complexities of food safety in epoxy resin applications

The applicability of a particular resin for food contact application is a rather complex topic to be covered in one sentence answer, so we decided to cover it in a discussion-like manner, exploring various aspects of the safety of the resin material. 

First of all, let’s talk about what exactly is considered to be “food-safe epoxy resin”? Although it seems fairly straightforward in the first place: i.e., the resin layer in contact with food should not leach any chemicals or contaminate food with particles, in reality, the definition of food-safe epoxy is not covered by regulatory bodies for DIY resin materials. There is simply no such regulation that tells what a two-part DIY epoxy resin composition should be, how it should be manufactured, packaged and applied to become food-safe. However, there are regulations exist that cover the food safety of coating materials intended for use in more industry-specific type of applications such as producing, manufacturing, transporting food and others.

A good example of such a regulation often used by manufacturers of resin coatings is United States FDA 21 CFR 175.300 Resinous and Polymeric Coatings. Despite its original purpose to provide the necessary guidelines and borderlines for industrial food contact applications, this regulation is also often referenced when it comes to marketing resins for arts, crafts and DIY applications. But is this strategy legit? Let’s take a closer look at this regulation. Simply put, the FDA 21 CFR 175.300 considers a resin coating food safe if it is manufactured from the list of approved raw materials AND applied and cured coating does not leach chemicals into food over a set limit at specified conditions. These conditions are standardized and are designed to cover the typical scenarios of the food contacting resin coating surface.  Since it is a lot to digest when reading the regulatory documentation from different countries, we have prepared an easy flowchart for you to gain an understanding of the idea on how the assessment works:

The flowchart above presents a simplified version of the resin assessment process. In reality, it is a more complex procedure that takes into account the specificity of the coating with respect to the food type and ambient conditions, such as food temperature, type, acidity or alkalinity, and alcohol content. For instance, a resin coating intended for contact with solid food may not be suitable for alcoholic beverages like beer. It is easily noticeable that the assessment is a two-part process, consisting of the analysis of the composition of the material (to make sure there are no harmful chemicals present such as lead or others) and testing cured coating (to make sure that the material is indeed inert and can withstand the conditions of use).

A real-life example of food-safe epoxy coating

A good example of a compliant food-safe epoxy would be the coating inside of a can of Coke. This coating serves as a barrier, protecting the can's contents from acquiring a metallic taste and preventing the aluminum from corroding or reacting with acidic or alkaline substances. The food safety of this coating is guaranteed because the epoxy composition has been specifically optimized for mildly acidic liquids stored at temperatures ranging from +4°C to +25°C. This coating is applied following optimized protocols and rigorously tested in quality control labs to ensure that no deviations affecting the safety of the material occur from one batch of aluminum cans to another. The accuracy and precision of the application process, along with strict quality control, are the key components contributing to the food-safe status of the coating material.

What about the DIY arts and crafts resins?

As you might have deduced from the information above, some of the important steps in food safety assessment are missing when we consider home-based resin projects. The whole idea of imagination and experimentation, those things that make the material fun to use contradict the food-safety status. Food safety is about boring, controlled, repeatable application of the material followed by comprehensive testing in the lab.  

These are some issues that can potentially affect the food safety of the material:

• Incorrect mixing ratio
• Insufficient mixing
• Incomplete curing of the resin due to the fluctuations in ambient temperature
• Temperature of the food
• Acidity or alkalinity of the food
• Concentration of the alcohol
• Pigment types and load levels
• Exposure of the hardener to carbon dioxide
• And many other factors

It is well known that undercooked pork meat can lead to serious health problems. Cooking pork in a way can be viewed as a similar process to curing epoxy resin.  While it is true that epoxy resins have the potential to be cured into a food-safe material, similar to how pork can be safely cooked for consumption, ensuring food safety when working with epoxy at home is a way more challenging and complex task.

Unfortunately, without access to specialized analytical equipment, it is nearly impossible for individuals to verify that the cured epoxy is food-safe confidently. In contrast, a simple and affordable thermometer is all that is needed to ensure that the pork meat has reached the temperature of 145 ºF, making it safe for consumption.

The product that I use right now is advertised as “food-grade” or “food-safe”! Now I am confused!

The food safety regulations for DIY resins are a gray area. As we have already covered above, manufacturers or resellers of various resin brands use, what we think, far-fetched tactics by trying to apply the regulations created and designed for industrial products to resins intended for home use. The reason for advertising their products as safe for food contact is simple - it is a great sales booster. There is a great demand for a product that is food-safe, proven by the number of questions we receive weekly about this topic. It is lucrative to cut some corners and get more sales. This is our view on the industry at Nerpa Polymers based on years of experience in polymer science.  

Here are some tips for you. They will minimize the risk of migration of resin components to food: 

• Use balances instead of graduated mixing cups. Measuring contents by mass is the most accurate way of making sure that the right amount of resin and hardener is used. Remember that 1:1 by volume mixing ratio does not necessarily mean it is 1:1 by weight
• Your ambient temperature should not fall below 20ºC when resin is curing
• Do not use strong household chemicals when cleaning the surface of coating
• Do not allow epoxy resin coating contacting with alcohol

Choose a responsible manufacturer

It could be an overwhelming task to choose the right product from the plethora of options available. At Nerpa Polymers, we do not only manufacture top-quality resin systems, but also aim to stay as transparent with our claims as possible and avoid questionable sales tactics. Instead, we focus on the real advantages of our products, such as bio-based nature, nonylphenol-free composition, absence of harmful accelerators and catalysts and other key features that differentiate our epoxy resins and colourants.