The study reveals the AhR toxicity of a pizza box
A Danish study from the Danish National Food Institute and Søborg University was recently published in the scientific journal Food additives and contaminants. It showed that there is still a lot to learn on toxic substances inside the paper and cardboard of food product packaging. Please note that this study comes from a larger study on the analysis of 20 different types of paper.
Tests revealed the presence of substances toxic to humans and the environment (AhR toxicity, see the following definition) in the chemical composition of a recycled food product packaging. This toxicity is equivalent to 47.9 nano-grams per kilo of the packaging of the most toxic dioxin: 2,3,7,8-TCDD (see definition below).
Definitions: AhR toxicity and dioxins
Aryl hydrocarbon receptor (or AhR): Protein encoded by the AHR gene in humans. It is a transcription factor, which means that its function is to “copy” gene data. It was shown that substances like 2,3,7,8-tétrachlorodibenzo-p-dioxine (the most potent dioxin) could lead to changes in genes transcription. This type of toxicity is called AhR toxicity.
Dioxins: Persistent organic pollutants in the environment. Very toxic, they can interfere with the hormonal system, cause cancer, cause developmental and reproductive problems, or weaken the immune system. There are more than 210 dioxin-like compounds, but only 17 are considered to have high level of toxicity.
2,3,7,8-tetrachlorodibenzo-p-dioxin or TCDD: Dioxin-like compound considered as the most potent. According to the International Agency for Research on Cancer (ARC), it is one of the most toxic dioxin for humans and, the only one considered as a carcinogen.
Understanding the scientific method used for the study
Preliminary tests
The authors of the study tested a sample coming from a pizza box made of recycled cardboard by boiling it in ethanol. The result showed an AHR toxicity equivalent to 47.9 nano-grams of 2,3,7,8-tetrachlorodibenzo-p-dioxin per kilo of cardboard.
To discover the source of this toxicity, the sample was then fractionated by high-performance liquid chromatography (HPLC) into 10 parts. The toxicity was concentrated in only two of the ten resulting parts. The analysis enabled to determine the presence of seventy-five substances in these two parts.
Analysis of the 75 substances found: which ones are responsible for the toxicity?
The authors chose fifteen of these substances because they shared similar structures with active AhR substances and were probably responsible for the toxicity. The detailed analysis from this list showed that only seven of these compounds were commercially available as preparations and could be measured in cell tests.
One of these seven substances showed significant AhR toxicity: “Solvent Violet 8”, a dye used in printing inks. But according to the main author of the study, it is only responsible for less than 1% of the toxicity…
The only other known sources of toxicity were the traces of dioxins, furans and PCBs in the packaging. Added up, all identified toxic substances accounted for just 3% of the toxicity.
Potential consequences of this study
The lack of knowledge on the toxicity of paper packaging: a challenge to overcome
This study shows the lack of traceability of toxic substances in papers and cardboards in contact with food products, and the lack of knowledge on the nature of these substances. In addition, it insists on the presence of dangerous substances in recycled paper and cardboards.
In an interview with Chemical Watch, the main author of the study highlights that the complexity of the traceability of the substances in the packaging comes, for instance, from the fact that “Paper products can be highly sophisticated, made of different layers, with surface coatings and printing inks, and then recycled as well. They are complicated products.”
The results are very interesting for regulators and paper and ink industries, as they highlight the difficulty of tracing toxicity in paper and cardboard packaging.
Will there be an increase in the controls on materials in contact with food products?
Nowadays there are only few controls on the chemical substances present in materials in contact with food products. However, industrial bodies like EuPIA (European Printing Inks Association), are favorable to a European framework that would prevail on national legislation. Indeed, they may be seen as trade barriers.
Regulatory framework on printing ink
At European level, regulation (EC) No 1935/2004 doesn’t authorize printing inks in contact with food
Today, the use of chemical substances in printing inks, coatings and every other material in contact with food is regulated by regulation (EC) No 1935/2004 on materials and articles intended to come into contact with food. However, the positive list of substances allowed in food contact materials does not include printing inks.
At national level: some advances in printing ink-related legislation
Switzerland: In Europe, the only legislation at national level, which frames the composition of printing ink used on packaging, is a Swiss Government Ordinance from 2010.
Germany: Germany planned an Ordinance on printing inks in early 2015. For now nothing has been amended by the European Commission.
Conclusion
This study highlights that little is known on toxic chemical substances in food product packaging. Currently, the toxicity of the analyzed cardboard sample is irrefutable, but its source is impossible to diagnose precisely.
This study makes way for new scientific investigations to remedy the lack of knowledge, and potential regulatory evolution when these toxic substances will be better identified.
You wish to learn more on food contact materials regulation?
Please don’t hesitate to contact us at contact@ecomundo.eu if you have any question or if you are looking for specific services. You can also call us at +33 (0)1 83 64 20 54 for Europe or at +1 (778) 234 1607 for North America.
