CHARACTERIZATION OF SHEET AND CONTAINERS OF ORIENTED POLYSTYRENE FOR FOOD-PACKAGING

Oriented polystyrene (OPS) has a very small diffusion asa primary food packaging material in Europe, compared with American and Japanese mar kets. This situation, however, could rapidly change due to the increas ing importance of semi-rigid packaging for novel foods. In this work, optical, diffusional and mechanical properties have been studied for O PS sheeting and thermoformed tubs together with an evaluation of their suitability for food contact and the appreciation of consumers interv iewed when leaving supermarkets. Both for the sheeting and for the fin ished containers were determined high gloss values, low haze, high mec hanical performance and safety indications from the migration tests, b ut low barrier properties against gases and water vapour transmission were found. The conclusions from the interviews with the consumers wer e quite in line with the objective analytical results. In fact, the co nsumers recognized the innovative character of the OPS tub suggesting its use for fresh and/or convenience foods (salads, cheeses, etc.): it ems with short shelf-lives, requiring limited protection against gas e xchanges but clear packaging for the best vision of the product.