Migration and Sensory Changes of Packaging Materials Caused by Ionising Irradiation

In modern food technology high requirements on the quality of products are made, especially with regard to odour, taste and shelf life. In order to increase the shelf life of foodstuffs for e.g. ionising irradiation and aseptic packaging is used. But the irradiation treatment of the packaging materials - in most cases plastics - can have negative consequences on the packaging materials and therefore on the food quality and on consumers care. Gamma-Irradiation of polymers generally leads to a formation of free radicals and ions, with secondary effects such as cross-linking as well as oxidative chain scission. Volatile radiolysis products are formed which may induce off-odours in the polymers and may change the migration characteristics of the packaging materials. Also additives are destroyed with increasing absorbed irradiation dose and may affect the specific migration behaviour of additives and additive-related decomposition products. In this study the migration behaviour and sensory changes of various plastics packaging materials (polyolefines, poly ethylene terephthalate, poly amide, poly styrole) after gamma-irradiation with 60Co is presented under consideration of different irradiation doses.