The mind wonders if one day we will have a futuristic kitchen appliance in which a pod (such as coffee pods for coffee makers) is inserted and our food product can be generated (or recomposed) in the appropriate serving size for our nutrition needs with custom sensory qualities and appealing shape.
“Flor de Cacao” is an amazing 3D printed chocolate creation by Jordi Roca, one of the world’s most creative pastry chefs, made possible using Barry Callebaut Mona Lisa 3D Studio. The Mona Lisa 3D Studio translates the realization of 3D printing on a commercial scale, allowing chefs to craft their own unique creations and reproduce them rapidly and affordably, no matter how intricate or specific the design (Barry Callebaut press release). Chocolate is a printable material with a well-defined solidification mechanism based on the crystallization behavior exhibited by cocoa butter1,2. Natural foods such as fruit and vegetables, however, show a short printability window. Meaning that the material can be printed with limited printing parameters. As an example, when a narrow nozzle is required due to the lack of or minor presence of solidification mechanism (the ink flows too much). These conditions imply a reduced flux of material and hamper upscaling. To enlarge the printability window and favour upscaled production, hydrocolloids3 can be added to provide a more stable flow and the desired paste-like consistency. Alternatively, the solidification can be triggered immediately after deposition by hydrocolloids that can undergo thermo-reversible or ionic gelation4.
Upscaling of multicomponent systems with time-dependent changes of the physical properties is a challenge. However, problem-solving and pursuing unmet needs are the key drivers to disrupt 3D food printing. Upscaling efforts should be devoted to directions where casting methods of foods into a mold do not attend the essential needs. For instance, the design of internal structures. Texture customization can be achieved by changing the infill percentages of the 3D printed object. Besides, 3D food printing allows freshly mixing of ingredients and has the potential to encapsulate probiotics, vitamins and nutrients through co-extrusion printing. This means that 3D printing technology will most likely not replace standard conventional methods of production but will diversify the food product offering.
Consumer perception cannot be overlooked. There are a lot of emotions surrounding food. As quoted by George Bernard Shaw: “There is no sincerer love than the love of food”. Each of us has a special relationship with food. Our love of food can be associated with memories from infanthood or even cultural beliefs. Noteworthy, 3D food printing is not meant to change the way we eat. 3D food printing should be seen either as a problem solver or a diversified way to deliver real food5. For instance, the technology can be used to encourage the consumption of vegetables and healthy foods for children. Fruit and vegetables can be converted into paste consistency and printed in the form of dinosaurs or any shape the child’s creativity allows. The user can go straight from a virtual model to the end-product. We cannot forget the recent boom in the demand for plant-based food. 3D food printing can perfectly meet the needs of the vegan population. Because 3D printing allows the construction of intricate geometries such as meat fiber, a steak can be printed with the same texture profile of the one animal-derived but using plant-based ingredients that can mimic the flavor of the meat.
A 3D printer can be installed in the most remote area. For instance, a 3D food printer could be used to fabricate fresh food for astronauts during space missions6. The consumer can produce food from scratch with total control of the ingredients used. The versatility of 3D printing is characterized by a decentralized food production model which opens opportunities to innovate. Jayaprakash and collaborators (2020) demonstrated that 3D food printing shows higher business potential for scenarios related to 3D printed snacks/meals in semi-public spaces such as fitness centers and hospitals. Their study has also revealed that personalized nutrition and convenience are seen as key desirable features of 3D food printing by both experts and consumers7.
Although much progress is observed at the component level of 3D food printing, food safety discussions are in the developmental phase. The commercialization of the technology either by the domestic use or retailing will require risk analysis on the shelf-life of the edible inks aligned with the hygienic design of the devices.
A brief history of 3D Printing
Additive manufacturing or 3D printing was introduced by Charles Hull in the early eighties. Hull used UV light to harden one layer at a time of UV-curable material and attach them layer by layer for making a 3D solid object9. Then, 3D printing technology emerged from around thirty years of deceptive period. Today, 3D printers can print a variety of materials ranging from metals, plastics, waxes, biological materials, and food. In fact, any material capable of solidifying can be produced additively. Powered by customization, 3D printing is exponentially unleashing the constraints of traditional manufacturing in several sectors. In the medical devices segment, 3D-printing attracted attention because the technology enables products to be completely matched with one’s body shape. Hence, 3D printers are used to print bone implants, prosthetic limbs, and mechanical-sensing devices10. 3D printing is the main technology used to fabricate hearing aid devices, with more than 10,000,000 3D-printed hearing aids in circulation worldwide back in 201311.
3D printing applied to design food constructs was first reported by researchers from Cornell University who introduced the Fab@Home Model. The 3D printer developed by them was capable of producing forms using liquids and semi-solid food materials12. Fab@home printers and most 3D food printers developed in the subsequent years are based on extrusion processes. In this type of 3D printing technology, a moving nozzle is used to extrude an edible formulation with consistencies ranging from free-flow to paste-like material. The edible ink is extruded out of the nozzle in a filament form and is deposited at points predetermined by a 3D model. Lowering the viscosity faster should be the solidification of the material to ensure adhesion between the layers and self-sustaining properties of the 3D printed constructs4,13.
Food Safety
Although we may consider 3D printing machines as an industrial machine or as a kitchen appliance the food safety challenges are similar and can be resumed to:
Edible inks
Food materials used to print would be processed goods from the food industry. Nothing very different from usual should be done by organizations or consumers to guarantee the safety of these raw materials. In fact, these raw materials, if commercialized in a frozen or dry state can minimize the risk of biological growth.
Cleaning
Cleaning is an important step to reduce the microbiological load of equipment and prevent cross-contamination. Cleaning of the 3D Printing machine should follow the cleaning and handling instructions provided by the fabricant. In an industrial setting, the organization should include the 3D printing machine on their cleaning procedures and check effectiveness regularly.
Hygienic design
The 3D Printers should have a hygienic design allowing to disassemble parts of the equipment where cleaning is paramount and assure that the materials used are food-grade preventing migration from its components to the products. Either for the industry or as kitchen appliance the materials should be resistant to cleaning products (and preferably to the use of home dishwashers).
Brittle materials should be avoided to prevent physical contamination (e.g. breakage of equipment parts). In a recent 3D food printing conference, Gaia Di Martino presented a cleaner and more hygienic 3D printer. The system consisted of a new extrusion system where the food is not in touch with the metal parts. The food is contained and squeezed into a high-density polyester container. The edible ink is extruded with the help of 2 peristaltic pumps to ensure homogeneous flow8.
Shelf-life
When used in the industry, shelf-life studies should be conducted to assess whether the production method may reduce or extend the shelf-life time defined for the product. The shelf-life is dependent on the commercialization route of choice: centralized production or not. The decentralized food production model foresees that the consumer will make use of food safe edible inks to produce 3D printed food. In this case, the 3D printed food is generally consumed immediately after production. The consumer can use fresh-food ingredients or industrialized food safe edible ink. Shelf-life studies should be conducted either for industrialized food safe edible inks or the 3D printed food reaching consumers through distribution channels as well as partnerships with retailers.
Looking forward
We live in a digital world where the information travels fast and there is a rising need for “personalization”. 3D printing technology has enabled personalization in aerospace, medical, pharmaceutical and, over the past decade, in the food sector. The disruption of the traditional food industry to personalized production, however, confronts many challenges. To make 3D food printing available for the population will require a robust business model and a lot of product development work in at least four dimensions: (1) printability, (2) upscaling, (3) consumer perception and (4) food safety.
Personalization and the capability of printing complex structures are unique features of 3D printing. Nevertheless, 3D food printing is built upon sustainability by reducing waste. Only the necessary material is used during printing to build the designed object. In addition, food by-products or foods that would otherwise end up in a waste can be utilized as ingredient inks and 3D printed into an attractive shape with delicious taste, characterizing an upcycling method.
There are identifiable food safety threats and hazards but outweighing these are the exciting innovative opportunities inherent in this technology.
Identified food-safety risks can be prevented if we reduce the number of steps in the food chain and production is brought closer to consumption! The mind wonders if one day we will have a futuristic kitchen appliance in which a pod (such as coffee pods for coffee makers) is inserted and our food product can be generated (or recomposed) in the appropriate serving size for our nutrition needs with custom sensory qualities and appealing shape.
This article was written with Fernanda C. Godoi
Disclaimer: The information contained on this article is based on research done in the last months and the authors personal experience and opinion. It is not intended to represent the view of any organization they work for or collaborate with. The authors will not be held liable for the use or misuse of the information provided in the article.
References
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