Magdalena Lubecki, Dr. Gabriele Steiner
Primary aromatic amines (PAA) can exist in color pigments. These are harmful substances, some of which are also categorized as carcinogens. According to the Federal Institute for Risk Assessment (BfR), consumers should minimize contact with these substances as much as possible. In view of this statement, in 2014 CVUA Stuttgart analyzed a total of 81 samples, including bakery bags, napkins and muffin tins, for the release of PAA into these products. The leaching of PAA was conspicuous in ten samples.
According to the requirements outlined in the BfR’s Recommendation XXXVI („Paper, Cartons and Cardboard for Food Contact“), no azo pigments listed in the annex of the Consumer Goods Ordinance may be used. In addition, PAA should be undetectable in water extracted from finished products (see Info Box), regardless of whether the PAA comes directly from the azo dye or from the recycled fibers.
Primary aromatic amines are amines with aromatic substituents; the simplest of these is the anilin (see structural formula). PAAs are substances that are used, e.g. in the production of specific pigments or so-called azo dyes, and remain in the pigment as a contaminant. Some PAAs are known to be cancerous for humans. Others are considered to be potentially carcinogenic for humans, based on the results of some animal experiments. As presented here, PAAs relevant to human health can leach out of colored paper napkins and bakery bags, as well as from other printed materials that come in contact with food.
For the interpretation of „undetectable“ the BfR recommends, in addition to the existing total limit value of 10 µg/L for PAA, an additional limit for the transfer of individual substances categorized as cancerous or potentially cancerous, such as anilin, toluidine and anisidine. In the opinion of the BfR, the ALARA principle should be valid for these PAAs (see Info Box). The transfer of PAA to food or food simulants should not be detectable above a limit of detection of 0.002 mg PAA per kg food/food simulant (2 µg/kg). Furthermore, the BfR recommends using only color pigments that do not contain any carcinogenic aromatic amino components.
The ALARA principle is a fundamental guideline for protection from radiation. The term is an acronym for "As Low As Reasonably Achievable". The challenge behind the ALARA principle is to minimize exposure to ionizing radiation so that damage caused to humans, animals and materials is kept as low as reasonably possible. This principle can be applied to any type of harmful or potentially harmful influence, such as exposure to the primary aromatic amines described here.
The recommendation made by the BfR is also being considered via a legislative proposal regarding the composition of printing inks (printing ink ordinance).
A total of 81 samples, including printed bakery bags, colored muffin tins and dyed-through/colorfully printed napkins, were analyzed for the presence of PAA. Ten samples (12 %) contained PAA in amounts higher than the above-mentioned limit recommended by the BfR. The results are presented in the graph below.
The sum of PAA was between 10 and 43 µg/L in eight of the 10 conspicuous samples. In six of the 10 samples individual substances such as aniline, o-Toluidine and o-Anisidine were found in amounts over 2 µg/L.
Production of the cold water extract.
In accordance with DIN EN 64, an extract of cold water was prepared for the sample. The sample was cut into small pieces, put in water at room temperature for 24 hours, and occasionally shaken.
The solution was then filtered, and any PAAs that might be present were then separated by means of liquid chromatography, using UHPLC (Ultra High Performance Liquid Chromatography) and detected by means of mass spectrometry.
Our results showed that colored prints still contain relevant amounts of PAAs. We will therefore continue to conduct these analyses in 2015. The BfR advises consumers to avoid the long-term storage of food in printed paper packaging or wrapped in printed paper napkins, especially with the colors red, orange or yellow. This confirms our findings from 33 napkins, 8 of which (24 %) were conspicuous.
 Opinion No. 021/2014 of the Federal Institute for Risk Assessment from 24 July, 2013, published (in German) under http://www.bfr.bund.de/de/a-z_index/aromatische_amine-4779.html
 Questions and answers regarding primary aromatic amines in printing dyes for paper napkins and food packaging, from the Federal Institute for Risk Assessment from 17 December, 2014, published (in German) under http://www.bfr.bund.de
 Regulation (EC) No. 10/2011 of the Commission from 14 January, 2011 for food contact materials (OJ, L 12/1, L 278/13), last amended via Regulation (EC) No. 202/2014 from 3 March, 2014 (OJ, L 62/13).