This paper gathers a number of significant results where nanotechnology was satisfactorily applied to improve packaged food quality and safety by increasing the barrier properties to oxygen of an ethylene-vinyl alcohol copolymer (EVOH) in dry and under humid conditions and of a poly(lactic acid) (PLA) biopolymer. The nanodispersion in the polymer matrix of modified monolayers of clays included in positive lists for food-contact applications is an adequate methodology to increase packaged food shelf-life. In spite of the fact that, in principle, there is no reason to believe that 'adequately' modified nanocomposites making use of substances in positive lists can impose any immediate risk threat for food-contact applications, further studies concerning potential migration issues and life-cycle analysis have to still emerge within the overall field of nanotechnology to corroborate the fact.

Poly(ethylene terephthalate) (PET) is one of the polymers most widely used in the packaging industry. However, it is highly desirable to enhance its barrier properties for applications, such as carbonated drinks and other rigid and flexible packaging applications. The nanocomposites route offers unique possibilities to enhance the properties of this material, provided that adequate thermally resistant and legislation complying nanoadditives are used. This study presents novel PET nanocomposites with enhanced barrier properties to oxygen, water, and limonene based on a new specifically developed food-contact-complying highly swollen montmorillonite grade, and, furthermore, presents and discusses morphological data. Moreover, given the current interest in the packaging industry to replace this material by other biopolyesters, a comparative barrier performance of PET nanocomposites versus that of biopolymers, such as poly(lactic acid) (PLA), polyhydroxyalkanoates (PHB, PHBV), and polycaprolactones (PCL) and their corresponding nanocomposites is also reported.