Poly(ethylene terephthalate) (PET) films (280-mu m film thickness), which are used in food packaging, were immersed into 160- and 320-ppm apple flavor solution for 14, 28, and 56 days at 5, 25, and 40 degrees C, respectively. At the end of this period, the changes in the PET films were investigated by measuring the mechanical and physical properties. The mechanical properties were determined by examining changes in the Young's modulus. The changes in the physical properties were investigated by Fourier transform IR spectroscopy and scanning electron microscopy (SEM). The formation of microcracks in the structure of PET films was observed by SEM. According to the results of those investigations, the apple flavor affects PET films, even at very low concentrations and temperatures. (c) 2005 Wiley Periodicals, Inc.