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.