New innovations for biobased packaging materials are announced on an almost daily basis. However, there are many things to consider related to their categorization, compliance, and safety – especially when they are used for packaging foods and beverages.
Niko Markkinen, a food contact material testing expert at Measurlabs, discusses four main issues that need to be considered when developing and purchasing such materials.
To be or not to be a plastic
Intuitively, plastics are associated with traditional petrochemical-based materials. However, also bio-based materials in contact with food may well fall within the scope of the Plastics Regulation (EU) No 10/2011 and thus need to comply with the same requirements.
By the regulation, a ‘plastic’ refers to a polymer to which additives or other substances may have been added, and which is capable of functioning as a main structural component of final materials and articles. Furthermore, a ‘polymer’ refers to any macromolecular substance obtained by one of three processes: a polymerization process such as polyaddition, polycondensation, or any other similar process of monomers and other starting substances; a chemical modification of natural or synthetic macromolecules; or microbial fermentation.
This means that even non-plastic packaging materials can be seen by the regulation as plastics, and thus need to be evaluated for their safety in the same way. It has been noticed for example that not all biobased materials sustain all migration test simulants as well as plastics do. While there is yet no other means for carrying out these tests, the biobased materials will have to pass this procedure in the same way as petrochemical-based plastics.
Cellulose as an ingredient in packaging materials is an interesting example in this topic. Regenerated cellulose film is controlled under Commission Directive 2007/42/EC of 29 June 2007, which contains the positive list of substances, the maximum total quantity of these substances, and the migration restrictions for this type of material.
However, regenerated cellulose films coated with plastics must also comply with Regulation (EU) No 10/2011 and pass the tests intended for plastic materials. As a third category, food packages made of paper and paperboard are predominantly cellulose, but for these, there is yet no harmonized legislation within the European Union. A bio-based food contact material is thus more than a sum of its parts and needs to be evaluated as a complete product to confirm which regulation or recommendation it should comply with.
The challenge of monomaterials and the presence of contaminants
At first thought, one could think that biobased materials as food packages would be a safer alternative to traditional plastics as the raw materials are of biological origin. However, biobased food contact materials (FCMs) carry risks for several contaminants which require special attention.
One of the main reasons why biobased materials require such elaborate testing for contaminants is the difficulty of creating them from monomaterials. Producing biobased materials from monomaterial is often difficult or even impossible, especially in cases where the raw material derives from the agri-food sector.
Raw materials such as starches and proteins are often acquired from various sources and locations, in which differing contaminants like heavy metals, persistent organic pollutants, pesticides, and biotoxins can be present. In addition, contamination by polycyclic aromatic hydrocarbons can also occur if the raw materials have been exposed to for example smoke from forest fires.
In addition to contaminants in the raw material, there is also a risk that contaminants like acrylamide formulate during the processing of biomass-containing materials. It is thus required to test not only for the substances originating from the different sources of the raw material but also to screen potential non-intentionally added substances (NIAS) introduced via contamination or formation during the manufacturing process.
Compromised shelf life and potential risks of barrier-improving additives
In 2019, Fera Science Ltd, UK National Reference Laboratory for FCMs, released a report regarding bio-based materials for use in food contact applications. The report concluded that using bio-based packages does not compromise shelf-life or consumer safety when compared to petroleum-based plastics. However, as this study was of a general nature and new materials are constantly being developed, the barrier properties of individual materials should always be tested or confirmed from the manufacturer to not risk customer safety.
To improve the barrier properties and anti-microbial properties of biomaterials, nanoparticles, nanodispersions, nanolayers, and nanotubes can be incorporated into the material. The materials include for example chitosan nanoparticles, cellulose nanocrystals, and essential oils. These types of nanoparticles have been assumed to be safe due to their inherently biological origins. However, current knowledge is lacking on the migration or toxicity of nanoparticles used in biobased food contact materials, and further studies are required to positively ensure their safety.
Allergens in the packaging material?
One interesting topic related to the safety of biobased materials is the possibility of allergens present in the material. At present, there is no evidence to indicate that biobased FCMs would pose an allergenic risk to consumers, but it might still be necessary for manufacturers to review the use of potentially allergenic components in their biobased packaging materials. For example for materials produced from protein-based raw materials this can be quite relevant.
Many of the challenges associated with biobased food packaging materials will be overcome as the industry as a whole becomes more adapted to this new era. Proper traceability of material streams from the agri-food sector, further research on possible health risks of additives, and broad testing of new innovations are the keys to success in the sector. The laws and regulations are constantly updated to answer to emerging challenges and better reflect the evolving industry.