Increasingly, a question arises among makers and in 3D printing communities: Which 3D materials is suitable for food contact? Can I use my 3D printed objects in the kitchen? Or… what materials can I print a bottle of? A glass? A cookie mold?
The answer to this question is much more complex and controversial than we might think without in-depth analysis. Because this question does not have a single answer but many, and very different from each other based on the 6 fundamental questions: Where? How? What? When? Who? Why? And… no… I’m not taking you by the wayside, follow me in my little analysis and you’ll understand the reason for this differentiation.
3D Materials: WHERE?
The first question to answer is: Where are we? Are we talking about the ideal world or our own? In the ideal world, no plastic should ever come into contact with food. For no reason. Be it the greenest/eco/super PLA, passing through PET and ending up with the worst kind of ABS. At this point I would not like to be taken for mad, so I allow myself to go a little deeper into the matter, with those (few) data that we have today. Let me start with the legislation.
The compatibility of plastics is enshrined in COMMISSION REGULATION (EU) No 10/2011 of 14 January 2011. It identifies a number of plastics that may come into contact with food and defines the amounts of migration of chemical components within them.
Although restrictive, this regulation has several shortcomings, first of all being dated, 5 years in research is a sea of time, secondly it does not take into account additives and dyes that refers to specific legislation of each Member State. And here we already understand that the place of production of the plastic (which cannot always be traced back) already determines the toxicity of the material.
Unfortunately, however, this is only the tip of the Iceberg.
Just as with smoking, real wars had to be fought before the manufacturers admitted the toxicity of their products, and despite the fact that smoking is now considered to be harmful to health, continuous production and distribution. For all bioaccumulative and non-metabolisable toxic substances that have a low level of acute toxicity, it is difficult to demonstrate the effects instantly, and long-term studies must be conducted on a significant number of individuals.
What we already know
All plastics have a number of additives, chemical compounds that serve to make the plastics softer, more resistant, hardeners, plasticizers and flame retardants. However, these substances are also released to the environment under special circumstances and function as endocrine disrupters. An endocrine disrupter is a substance that penetrates an organism and occupies sites intended for certain hormones, essentially reducing the body’s ability to respond to given stimuli. All this is associated with the onset of serious diseases.
How does the release work?
IThe release of phthalates, BPA and PBB from plastic containers and food films is favoured by the presence of fats, both animal (butter, cheese, etc.) and vegetable (oil, almond cream, avocado, etc.) and alcohol. High temperatures (the coffee in the machine) and acidity (as in the case of tomato sauce or sparkling water) also seem to favour the deconstruction of plastic materials.
Phthalates, PBA and PBB are immediately recognized by the body as harmful, and since it is not possible to metabolize and expel them, as a defense mechanism, they are deposited in the adipose tissue (fat). This is a problem because they are released in large quantities during periods of slimming (this is the excuse you were waiting for not to put yourself on a diet!).
Harmful substances released from plastics
After talking about it, here is a brief description of the most famous and well-known additives in plastics:
Bisphenol A or BPA is a chemical compound used for over 40 years in the production of plastics for food contact (feeding bottles, plates, cups, carafes, dishes suitable for microwaves and various containers) is also used in plastics that internally coat cans and metal boxes. Although it is an endocrine disrupter, the presence of which in high doses has been linked to a series of serious health problems, in 2006 the European Food Safety Authority set a migration limit of 0.05 mg/l for safe exposure per kg of weight per day, even for newborns. However, new studies have led to a total ban on this compound in 2011 for the manufacture of infant feeding bottles (infant feeding only).
The U.S. Department of Health issues these guidelines:
- Discard containers containing BPA that have scratches, even the smallest, as the transfer increases considerably.
- Do not heat or put plastic containers in contact with hot food and drinks, as the release is amplified (in the face of the boiling bottles that we have sucked by infants)
Among the main diseases associated with taking BPA we have:
- Learning and behavioural disorders
- Lowering of the immune system
- Early female puberty and fertility problems
- Decrease in the number of spermatozoa
- Cancer to reproductive devices
Phthalates are widely used in the production of plastics due to their plasticizing power. In reality, they are ubiquitous (nail polish, shampoo, paint, etc.). They have been so widespread in the last century that they are practically omnipresent, including in foods of animal origin (butter, poultry, milk, meat in general, obviously more present in fats).
Phthalates are endocrine disrupting chemicals and have been linked to a wide range of developmental and reproductive effects, including:
- Reduced sperm count
- Testicular atrophy or structural abnormality
- Liver cancer
- Type 2 diabetes
- In addition, in new experiments, phthalates have been found responsible for a pathology that affects the development in male offspring, leading to cryptorchidism (late or no descent of the testicles) at birth and tumors in the testicles later in life.
Brominated flame retardants are compounds used to prevent or delay the spread of flames in case of fire. This stands for 5 distinct groups of chemicals, and although the majority have been banned (at least in Europe) for TBBP-A, production is still increasing. These compounds are also ubiquitous as well as in plastics, and have now fully entered the food chain. That is why the EU has asked member states for population screening to assess the quantities of these compounds in our bodies. After the first studies, they found the presence of these flame retardants in the blood of the examined individuals, even if on average they were 10 times lower than the concentrations found in American citizens.
Generally, brominated flame retardants have rather low acute toxicity, i.e. it is necessary to be exposed to high concentrations in order to suffer immediate pathological consequences. However, prolonged exposure to these toxins can lead to:
- Incorrect brain development in the fetus
- Incorrect development of the fetus
- Interference with thyroid hormones
- Onset of tumours
After the short scientific interlude, we return to our Where. After saying that in the ideal world we must not put plastic in contact with food, we move on to evaluate ours. In our world it is very easy, indeed safe, to find food sold in plastic packaging. Butter, cheese and vegetables are already commonly contaminated. And our unconscious use amplifies everything! Do we have to heat vegetables boiled in the microwave? Why not use a nice plastic bowl? Or a small box of tuna in olive oil kept in the box coated with Bisphenol A? Better not! Then let’s have a steak in a non-stick stone pan. The “stone look” pan, to tell the truth, the stone has never seen it! So what is it? Simple…plastic, which we are heating up.
In a world like this, do you care if you use plastic printed by you in contact with food? If the answer to this question is at least read the “how”.
3D Materials: HOW?
If you still want to use food contact plastic, whether printed or not, you should pay attention to a few rules.
First of all, it must be borne in mind that even the new and amorphous food PET (that of water bottles to understand one another), considered one of the safest plastics, is recommended to be used only once! The manufacturers themselves do not recommend reusing the same bottle and filling it again, because with aging it tends to release substances (those we talked about earlier). The same goes for those who have taken a “heat stroke” (as we know, heat helps). Heat and contact with acids, fats and water deconstruct plastics to try to understand how we say: At least cold. Let’s try to put food and plastic in contact with each other cold, and for the shortest possible time! We try to follow the advice of the American Ministry of Health:
- Discard containers containing clearly damaged that have scratches, or consumed, because the transfer of toxic substances increases considerably.
- Do not heat or put plastic containers in contact with hot food and drink, under these conditions the release is amplified.
3D Materials: WHAT (Materials for 3D printing)?
What 3d materials can we use? We still want to create something that comes into contact with food, what to choose? If absurdly respecting what has been said so far, we want to create a form for biscuits, because: it can be used cold and stays in contact with food for a very short time. Which material can we choose?
We can say that starting by choosing a certified material for food contact is a good start, even if we know that it will certainly contain all the chemical substances (except BPA) analyzed before. If we are lucky it will have just few others. Probably the certification has obliged the manufacturer to use dyes or thickeners that comply with the laws (at least of the time and place of production).
3D materials: Best chose
The best solutions are the PLA of known origin, produced by companies that work in certain countries that are required to comply with strict environmental and hygiene laws.
Being biodegradable, however, releases the substances that compose it very quickly and therefore in greater quantities per unit of time in particular circumstances.
For this reason the PLA in contact with food, especially if liquids, fats, acids, alcohols, and at high temperatures should be used only once and then compacted.
Another solution is PETG, preferably certified for food use. The food certification proves that it is a new PETG, that is, with a percentage of recycled plastic inside of less than 50%. This figure is important because the plastics of the “past” could drag with them toxic products or arrive from countries with different legislations.
Again, as with water bottles, it should only be used once.
Absurdly, a similar argument applies to ABS, which emits toxic fumes during extrusion but probably has the same rate of release of toxic chemical particles as PETG once extruded, as well as having the same resistance to acids, fats and temperatures.
3D Materials: WHEN?
“A little coughing? Smoke a nice cigarette that disinfects. This was said in the early twentieth century, before medical studies showed that the few positive effects of smoking are subdued by the sea of diseases that bring this vice. In all likelihood, our time will be the equivalent for plastics. Plastic everywhere. In this sea of plastic it is practically impossible not to come into contact with this material. So trying to avoid it, at least at the table, would be a good thing!
And with this we get to who.
3D Materials: WHO?
Are you a healthy adult with children? Don’t you plan to have more? Then it probably won’t be the coffee in the machine or the steak in the non-stick pan that kills you, or at least not sooner than the cholesterol in the meat will do.
Speech changes radically if we talk about pregnant women, children in development or infants. In the cases listed, with the inclusion of couples who wish to have children, I would advise against coming into contact with plastic, or otherwise try to avoid it as much as possible, whether in contact with food, in clothing, and in general in everyday life. Think that PBBs (flame retardants) are also found in the pillows and mattresses with which we spend 1/3 of our lives! As I said before, the presence of endocrine disrupters can be crucial in the developmental stages of the fetus and the newborn, so in the case of both future mothers and babies, it is better to move towards glass containers, and forget about plastics for a while.
3D Materials: WHY?
Why is the real question, why, since we know all these things, is plastic still so present in our diet? Why do you still want to use plastic in contact with food after all you have read? You can’t give up cookies in the shape of a Christmas tree! Or Snowman! Or to make the New Year’s Eve toast in a glass printed by yourself! Well then do it. If it makes you feel safer, do not use ABS but only certified filaments for food contact. However, you should be aware that the differences are minimal. And these are just some of the many variables that we do not yet know.
3D Materials: Summary
All this endless article can be summed up in a single rule of life: we try not to let plastic and food come into contact, but if we really have to / we want to do it, at least we use plastics not damaged and change them often, but above all we do not use it to contain drinks and hot food!