The Migration of Chemical Contaminants from Polyethylene Bags into Food During Cooking

Abstract

Cooking food in polyethylene bags has of late substituted banana leaves in Uganda. However, such a practice is risky as chemical contaminants may migrate from polyethylene bags into food during cooking causing health complications. Therefore, this study was done to identify and quantify the levels of chemical contaminants (heavy metals) in black and green polyethylene bags. Polyethylene bags were ashed and digested with acid and heavy metal concentrations determined using an AAS. Samples analyzed contained heavy metals with concentrations ranging between; 1125 - 1725, 76 - 112, 35 - 52, 18 - 31 ppm for Pb, Cd, Cr and Co respectively. Heavy metal migration studies into posho cooked in the black polyethylene bags was done at 65 o C (T1), 80oC (T2) and 95 o C (T3). The highest migrated heavy metal concentrations 120.60, 12.25, 9.45 and 15.42 ppm for Pb, Cd, Cr and Co respectively were obtained at T3 at the surface of the posho cube (0.5cm) after 5 hours of heating. While the lowest values for Pb (10.60 ppm), Cd (1.26 ppm), Cr (0.20 ppm) and Co (1.55 ppm) were obtained at T1 towards the centroid of the posho cube (1.5 cm) after 2 hours of heating. Pb migrated highest followed by Co, Cr and Cd. Though small quantities migrated, over a long period of time they may accumulate in the body and cause health complications to the victims. To make this research of substantial importance to the polyethylene bag user, the findings were disseminated through media to the general public.