Evaluation of e-beam, gamma- and X-ray treatment on the chemistry and safety of polymers used with pre-packaged irradiated foods: a review

Polymers used to package food intended for irradiation must currently recei ve separate US FDA approvals for e-beam, gamma and X-radiation. The three f orms of irradiation have virtually indistinguishable effects on polymers he ld in vacuum. However, in air, irradiation damage is favoured by slow dose rates, such as that characteristic of gamma irradiation. Irrespective of ir radiation type, theory and existing polymer irradiation literature both sug gest that radiolytic products in food contact polymers should not present a health hazard due to migration into the foods they contain. Equations are presented which calculate the FDA allowable content of radiolytic products to achieve 'threshold of regulation' clearance and conversion of radiolytic yield values (G-values) into ppb concentration in the treated polymer in c onformance with FDA practice. An approach to quantifying the functional bar rier of a polymer is discussed.