Printing inks for food packagingstudy of the key parameters in the migration of photoinitiators

Abstract

In the last 50 years, the UV-curing inks began to substitute the classical solvent-based inks, obtaining better printing packages, safer for the consumers and with less impact for the environment. Nevertheless, since 2005, when the European food safety authorities have found photoinitiators in packaging of milk for babies from these inks, they become in an important food safety issue worldwide. The main objective of this thesis is going deeper in the knowledge about the migration of photoinitiators and their degradation products into the food. To address this objective, this thesis is divided in three main parts. Firstly, a review about photoinitiators is presented from the food safety point of view, explaining what they are, how they migrate into the food, what is their legislation over the world and which strategies can be followed for their detection (with the problems and peculiarities that this fact implies due to their action mechanism). Following, different analytical approaches have been described for the determination of the photoinitiators and their byproducts by multiple techniques, from the classical HPLC-DAD and GC-MS to the novel LC-ESI-MS/MS, UHPLC/ESI-HRMS and DART-HRMS. The last section of the thesis studies the migration kinetics of 6 of the photoinitiators that produce more food safety alerts and notifications in the last years. These studies were carried out at all the common temperatures of food storage in all the food simulants present in the current legislation (except for dry foods), from the polymeric material most used in food packaging, LDPE. Thereby, the mathematical model developed from these data allows the prediction of their migration to the foodstuff almost in any case.