Effectiveness of polypropylene film as a barrier to migration from recycled paperboard packaging to fatty and high-moisture food.

The capability of a polypropylene (PP) film barrier to prevent migration of residual contaminants from recycled paperboard into food simulants was studied. Anthracene, benzophenone, methyl stearate and pentachlorophenol were chosen as chemical surrogates to represent classes of contaminants likely to be found in recycled paper/paperboard. Each surrogate was spiked into a test specimen made of seven thin virgin paper layers at concentrations of 1-50 mg kg(-1). Test specimen were dried, stacked and sandwiched with PP films, laminated with PP film and then subjected to migration experiments using a compression cell maintained at 100 degrees C for 2 h. The concentration of the surrogates in the test specimen and in 95% ethanol, isopropanol and 10% ethanol food-simulating solvents was determined by gas chromatography with flame ionization and electron capture detection. The results show that although the concentrations of the surrogates in the food simulants decreased with an increase in PP film thickness, they were still high and generally resulted in dietary concentrations >0.5 microg kg(-1), the level that US Food and Drug Administration would equate with negligible risk for a contaminant migrating from food packaging. Only at the lowest spiking level (1 mg kg(-1) benzophenone) did migration from the paperboard through a 0.127-mm PP film result in a dietary concentration of </=0.5 microg kg(-1). Therefore, it can be concluded that for an extended time at 100 degrees C, PP would not be an acceptable barrier to migration of contaminants that are expected to be in post-consumer paper/paperboard.