Migration of Photoinitiators in Food Packaging: A Review

Abstract

Photoinitiators are highly photoactive compounds included in the formulations of UV curing printing inks and varnishes. Twenty five of those photoinitiators can be found in the bibliography regarding food packaging migration and analytical methods with an increasing interest in the last 9 years because of the foodstuffs contamination with 2-isopropylthioxanthone detected in 2005. An overview about migration of photoinitiators in food packaging is firstly given in terms of Rapid Alert System for Food and Feed notifications, mechanisms of migration, and specific migration limits. Besides set off, a migration model based on diffusion and partition coefficients is considered to analyse the factors affecting migration: physicochemical properties of the photoinitiator, characteristics of the foodstuffs and food simulants, temperature and packaging. Molecular weight, volatility, polarity and lipophilicity are considered as the main physicochemical properties of the photoinitiators playing a role in migration. In relation with the food packaging, information from published works is reviewed, taking into account the special migration behaviour of paper and cartonboard as well as the efficiency of different plastic films as barriers to avoid or reduce migration. Results of the application of the migration model are compared with reported data from the bibliography. Finally, the use of polymeric multifunctional photoinitiators is concluded as the best option for ultraviolet curing inks and varnishes to print food packaging. They have higher molecular weight together with fewer and lower volatility photodecomposition byproducts and a higher probability than conventional photoinitiators of being bound into the cured polymer matrix.

Functional Barrier Performance of a Polyamide-6 Membrane Towards n -Alkanes and 1-Alcohols

“…Therefore MOSH and MOAH can be found in (nearly) every cardboard packaging material which has been manufactured by use of a certain amount of recycled fibres . Also compounds from printing inks had been found in cardboard packaging materials, from which they can migrate into food or food simulants . The use of functional barriers seem to be a practical way to reduce the contamination of MOSH, MOAH and other contaminants in cardboard packed food.…”

Comparative study of ink photoinitiators in food packages using gas chromatography with vacuum ultraviolet detection and gas chromatography with mass spectrometry

“…One of the key components of printing UV‐cured inks is photoinitiators (PIs). These chemical substances are highly photoactive due to containing photosensitive groups to initiate polymerization reactions for curing inks and lacquers under UV light . In carton board or plastic food packages, they can exist mainly as residues during printing.…”

Efficient initiation of radical‐mediated thiol‐ene chemistry with photoactive silica particles

“…The majority of these strategies rely on photo‐induced processes and the use of commercially available low molecular weight photoinitiators might pose concerns when it comes to the extractability of unreacted photoinitiator molecules or cleavage products. The migration tendency and volatility of conventional photoinitiators is also a key issue in printing inks and coatings . One efficient approach toward lower migration, reduced odor and improved compatibility in resin formulations involves the synthesis of polymer based photoinitiators with photo‐fragmenting or H‐abstracting building blocks .…”