Migration of model contaminants (ethylene glycol, DEHA and DEHP) from PET bottles into Iranian yogurt drink

The migration of di-(2-ethylhexyl) adipate (DEHA), di-(2-ethylhexyl) phthalate (DEHP) and ethylene glycol from PET bottles into the Iranian yogurt drink was studied. According to European Commission regulations acetic acid (3% w/v) was chosen as stimulant. The acetic acid samples were stored at 4, 25 and 45 °C for four months and analyzed periodically by gas chromatography. Differential scanning calorimetry (DSC) was used to investigate if contact with the food stimulant could affect the PET material. It was concluded that the storage temperature had a great effect on the migration of DEHP, DEHA and ethylene glycol. Also increasing storage time resulted in higher concentrations of migrating substances. The concentrations of migrating substances did not exceed their specific migration limit (EEC regulations). Determination of glass transition (Tg) and crystallinity of PET bottles using DSC method showed that the variations in the migration rate of selected contaminants during the time did not relate to the change of PET material in contact with 3% acetic acid.