Assessment of Phthalates Migration in Polyethylene Food Packages: A Case Study in Ghana

Abstract

The use of plastics such as polyethylene in the food industry in Ghana as opposed to traditional forms of packaging such as the use of leaves and paper is constantly growing with different designs and compositions. These plastics contain chemicals that are added during the manufacturing process. These chemicals, such as plasticizers, are used to make the plastics flexible but are not covalently bonded to the polymer, hence are able to migrate from the food packages into food when heated or stored for a long term. In this regard, plasticizers such as phthalates from food contact materials have raised many concerns due to suspected carcinogenic effects in humans. Other effects due to the exposure to phthalates include damage to liver, kidney, heart, and lungs as well as adverse effects on reproduction, development and blood clotting. Five different polyethylene packaging materials including: black polythene bags, plain polyethylene bags/films commonly called take away bags, polyethylene plastic bottles, thick plain polyethylene bags/films and polyethylene food containers were assessed. Total of four phthalates were soxhlet-extracted and identified by GC-MS. The extent of migration of the phthalates into food was assessed using food simulants (distilled water for aqueous food and olive oil for fatty foods) by varying exposure times and temperatures. The results indicated that the four phthalates under investigation were all detected in the polyethylene packaging materials. DBP was detected in all the polyethylene samples. DEHP was detected in 20 out of 25 polyethylene samples. The concentrations ranged from not detected to 14.30mg/kg for DEHP, 3.60mg/kg to 15.45mg/kg for DBP and not detected to 5.14mg/kg for DEP. BBP was detected in only one out of the 25 samples analysed with a concentration of 1.43mg/kg. The migrated phthalates from the polyethylene packaging materials into the aqueous food simulant were detected in trace concentrations with average values of 1.68μg/kg for DEHP, 0.60μg/kg for DBP and 0.01μg/kg for DEP. The migrations of these phthalates in the aqueous food simulant were all below the EU specification for phthalate migration in food contact materials. The migration of phthalates in the fatty food simulant however showed very high concentrations of phthalates migration from the polyethylene packaging materials into the olive oil. The migrated concentration of DEHP and DBP ranged from 0.69mg/kg to1.60mg/kg and not detected to 1.43mg/kg respectively. The rate of migration of phthalates from the polyethylene packaging materials into food simulant increased with increasing temperature in both food simulants. The results indicated that 28.13% and 34.38% of the migrated DEHP and DBP in the fatty food simulant exceeded the SML for food contact materials according to the EU regulation. Migrated BBP was however not detected in the fatty food simulant (olive oil).