Benjamin Horemans, Hendrik De Ruyck, Jan De Block, Lieve Herman, Bruno De Meulenaer

Research output: Contribution to conferencePoster


Convenience food is well established in many Western-European countries, and its popularity is expected to increase even more over the next few years. In order to meet consumers’ expectations, food manufacturers constantly look for innovative applications to heat their products inside their packaging, following strict European regulation on food contact materials (2004/1935/EG). However, the use of prints on ovenable and microwaveable food contact films remains challenging. Solvent-based inks for food contact materials often contain nitrocellulose, which dissociates and releases nitrogen oxides (NOx) upon heating. It is assumed that these NOx react with amines in food to produce carcinogenic nitrosamines. The packaging sector is aware of this problem and guarantee their costumers’ safety through preventive measures. However, since alternative inks or additional packaging increase the overall cost, and since it is not sure that every retailer is completely aware of the formulation or risks related to nitrocellulose-inks, one fears that not everyone takes necessary precautions.
To the authors’ knowledge, this study is the first to report fundamental experimental results on the formation of nitrosamines upon heating nitrocellulose-prints on food contact materials. The release of NOx from printed packaging foils upon heating was studied in a closed flask, from which the air mixture was continuously sampled by a NOx analyzer. The formation of nitrosamines was studied using migration cells, filled with a buffered amine solution (1 mM, pH 3.2) and covered with a printed polypropylene laminate. Nitrosamines were concentrated using solid phase extraction (SPE) and analyzed with capillary gas chromatography coupled to positive chemical-ionization mass spectrometry (GC-PCI-MS).
The release of NOx from nitrocellulose-containing prints on food packaging foils, increased exponentially with applied temperature. The amount of NOx set free upon heating seemed significant from 90°C and above. When heated in a migration cell (area/volume = 1), such a release could theoretically give rise to a substantial amount of nitrite in solution, provided that the migration of gaseous NOx to the food matrix is maximal. Kinetic studies on the nitrosation of dimethylamine demonstrated a second order dependency in the nitrite concentration. After incubation (2.5 h at 90°C), 2-20 µmole l-1 nitrite reacted to produce 0.13-21 µg l-1 N-nitrosodimethylamine (NDMA). By incubating the amine solution in contact with the printed foil for 2.5 h at 90 and 130°C, about 100 and 600 ng l-1 NDMA was found, respectively.
Compiling these results, one can conclude that a significant fraction of NOx released by the printed food contact material ends up in solution as nitrosating reagent, giving rise to carcinogenic nitrosamines. However, more elaborated research is needed in order to fully understand the fundamental mechanisms, and to validate these findings for real food matrices and contact materials.
Original languageEnglish
Publication statusPublished - 20-Nov-2014

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