Food-Safe Epoxy Resin: The Truth!

Today we talk about food-contact epoxy resins and their difference from non-food-grade epoxy resins.

Let's clarify when and how to use them.

Are non-food-grade resins truly toxic? Or is this information not entirely accurate, and nobody is explaining how things really stand?

Let's begin.

DIFFERENCE BETWEEN FOOD-GRADE RESIN AND STANDARD RESIN

1 The difference between food-grade resin and standard resin lies in the ability of the former to withstand prolonged contact with certain specific solid or liquid foods, exclusively at room temperature.

So let's debunk the first myth: not all foods necessarily need to come into contact with a food-grade resin.

Here is an immediate example: did you know that in Italy, the use of wooden paddles and wooden shelving for bread and pizza has been banned from professional use by law, as they are a source of bacteria? So let's start from the fact that while hardened resin resists the aggression of chemical agents such as thinners and acetone for several minutes without any issue, a material like bare wood is banned by law and releases bacteria. Despite this, everyone still uses wood — so start asking yourselves some questions.

WHAT FOOD-GRADE RESIN ACTUALLY MEANS

2 It has nothing to do with temperature. Food-grade resin simply means it can come into contact with cold foods — do not be misled by false myths. Epoxy resin can come into contact with warm foods, but it is not designed for that purpose. It is designed solely to contain food and beverages and nothing more. Whether it can tolerate brief contact with warm foods for a few minutes is a separate matter, which we will address shortly.

CHEMICAL SUBSTANCES RELEASED INTO FOOD

3 How can I be certain that resin does not release chemical substances into solid or liquid food? Simply by ensuring that only cold, room-temperature foods come into contact with the resin.

THE ISSUE OF TOXICITY AND BACTERIAL CONTAMINATION

4 Let's start with a common example. A wooden chopping board, even when dry, is a source of bacteria because it remains a living material.

If you put boiling soup into a plastic plate, it does not always happen — but often — the plate softens. So are you truly certain that resin is the only thing to be concerned about?

WHAT DOES HARDENED RESIN RESIST?

5 Epoxy resin, regardless of type, once hardened is inherently resistant to chemical solvents such as acetone, nitro thinner, alcohol, and so on — not indefinitely, but for several minutes or even hours depending on the type of solvent.

Based on this, do you genuinely believe that resting a biscuit, a slice of bread, a piece of raw meat, or some carrots on cured resin would cause it to dissolve and release chemical substances? Let's be serious.

THE ISSUE OF FOOD CONTACT WITH RESIN

6 Consider this: if you place a slice of lemon on a wooden chopping board, the wood can carry bacteria just as much as a next-generation PET surface or an Okite kitchen countertop — so much so that wood has been banned by law from pizzerias and bakeries. The concern that hardened resin is reactive applies only in extreme specific conditions, because resin is an inert body and, unless subjected to sustained high temperatures over time, it cannot alter its chemical structure.

RESISTANCE TO LIQUIDS AND SOLIDS OVER HOURS OR MINUTES

7 With these premises established, let's discuss the resistance of food-grade resin versus standard resin. Resistance to chemical agents — preventing them from softening the solid structure and causing it to release chemical substances into food — is measured in hours of contact between the resin and the chemical substance. To give an example: acetone or nitro thinner, which are extremely powerful and toxic agents, require several minutes — roughly an hour or more — to begin penetrating the resin. This leads to a clear consideration: if chemical solvents breach the barrier in approximately one hour, how long would wine, olive oil, or water take? It is therefore highly unlikely that beverages or common household foods could attack the resin in any meaningful way.

THE TEMPERATURE LIMIT

Let's address temperature. Epoxy resin withstands reasonably high temperatures, and each resin has its own specific characteristics, so it is not possible to determine exactly at what temperature any given resin will begin to soften. However, one thing is certain: for catalysed and hardened resin to begin softening and releasing toxins, it must be subjected to sustained and elevated heat for a considerable number of minutes.

Example: you take a slice of meat from the pan and place it on a resin and wood chopping board. Suppose the meat is at 80°C — this temperature will drop immediately within a few seconds, likely falling to 40–50°C. After all, if that were not the case, we would burn our mouths trying to eat it. We all wait a few seconds or a minute before eating hot food, but meat cools rapidly, as does broth, soup, or pasta — so there are no conditions under which resin could begin the process of softening and releasing toxins.

The temperature at which a resin begins to soften generally starts at around 70 degrees Celsius. This means that if the resin reaches 70°C and remains at that temperature for one to two minutes, this reaction begins — but it takes several more minutes before actual softening occurs. No food remains at that temperature for more than one or two minutes, so the resin cannot be affected.

Furthermore, if it is the meat or broth that is at 80°C, it would need to maintain a constant temperature long enough to transfer that heat to the resin substrate. But if the heat of the food drops and does not remain constant, the resin will never reach that temperature — and therefore will never release toxins in any meaningful sense.

Every case is unique, but this reflects the realistic scenario in general terms.

The Kustom Service resin has a Glass Transition Temperature (TG) ranging between 60 and 70 degrees Celsius, and a version rated at 108 degrees Celsius will be available shortly — so even placing a searing hot slice of meat on it will cause no damage whatsoever.

FINAL CONCLUSIONS

• Food-grade resin exists to contain food and beverages at room temperature, not hot ones
• Resin can contain warm foods for a few minutes, though this depends on how hot they are and for how long the resin is exposed to heat
• Epoxy resin cannot be used for cutting or slicing food, as scratching the surface would release a powder that is as toxic as that produced by plastic or wood from any standard kitchen chopping board
• Food-grade epoxy resin differs from standard resin solely in its ability to remain in prolonged contact with liquids such as wine or olive oil for days, weeks, or months, and with warm food for a few minutes, without its structure beginning to soften. This last point, however, has absolutely nothing to do with the rationale or certification behind food-grade classification

IN CONCLUSION

In this article we have clarified a very important topic. If you would like further information, write to our editorial team at [email protected] to suggest new topics or ask additional questions — we will do our best to respond to everyone.

You can find our food-contact epoxy resin at the following link on our website:

K-FOOD

Enjoy,

Dr Christian Bertolini