Mass transport studies of model migrants within dry foodstuffs

Cereals are widely consumed foodstuffs and it is therefore important to take them into account when estimating consumer exposure to packaging-related chemicals. The mass transport of three model migrants (diphenylbutadiene, triclosan and BHT) from low-density polyethylene (LDPE) within dry foodstuffs of different particle size (rice and wheat flour) was studied because of the relationship between consumer exposure and possible harmful effects on human health. The conditions that most affect the mass transport of substances within dry foods are evaluated and discussed. The diffusion coefficients (D_F) for diphenylbutadiene (DPBD) and triclosan in the studied foodstuffs were estimated. The D_F values for DPBD and triclosan in wheat flour at 25 °C were 7.1 × 10⁻⁸ cm²/s and 3.3 × 10⁻⁸ cm²/s, respectively. The D_F values for DPBD and triclosan in rice at 25 °C were 4.7 × 10⁻⁸ and 4.3 × 10⁻⁸ cm²/s, respectively. BHT displayed different behaviour and other tests were therefore carried out to elucidate the associated mass transport process.