Emission of additives and degradation products from commercial polypropylene, polyethylene and their composite packages

Migration is a known phenomenon defined as the partitioning of certain chemical compounds from plastic food packaging into food and has been intensely investigated in recent years. Due to outstanding chemical and physical properties plastics are used in many fields. Polypropylene and polyethylene are extensively used polymers because of their chemical resistance, high tensile strength and low density. To improve the properties of the plastics, additives such as plasticizers, stabilizers, antioxidants, lubricants, pigments and others are required to be added. However, they can migrate from the plastics into the food and contaminate it during production or storage. Therefore, the aim of this study was to investigate commercial polypropylene and polyethylene packages to determine what most often used additives and degradation products of the food packages can migrate to food. After the initial identification of plastics by Fourier-transform infrared spectrometry, the determination of cadmium, chromium, lead and mercury was carried out by atomic absorption spectrophotometry. To evaluate possible volatile and semi-volatile organic compounds thermal desorption gas chromatography coupled with mass spectrometry was used. The results revealing the presence of different potential organic compounds and metals emitted during the degradation process of different types of food contact materials are discussed.