Identification of Packaging Material of Foods by Infrared Spectroscopy

Abstract

In recent years plastic films have become widely used for food packaging. Further, there are many cases where different types of plastic are laminated or plastic are coated or laminated on paper or metal foil.Among these, there are few cases that toxic additives may be present. Hence, there is a need to discriminate the types of packaging material in order to assure the safety of foods. However, with the existing transmission of IR, the absorption band might become complicated by the lamination or, in case of laminated paper or metallic foil, determination becomes impossible. Hence, a discrimination of packaging material by Attenuated Total Reflex (ATR) spectrum method was performed.By measuring the transmission and the outer and inner sides of IR it is possible to determine the types of plastic laminated. This method was especially effective in the identification of paper or metallic foil laminated with plastic.From the results of measurements made on about 100 packaging material of foods it was found that polyethylene was used most in contact with food, followed by polypropylene. There were no cases where polyester or polyamide was used in direct contact with foods.