Chemical migration from secondary packaging materials

5 Chemical migration from secondary packaging materials 

Transfer of substances from secondary packaging to foods can be considered to take place by two main routes. The first is via direct contact where the 

Substances linked with producing odour and taint include short chain aldehydes. In paper and board, these are considered to derive from the degradation of lipids. Pentanal, hexanal, heptanal and nonanal were shown to be volatilised from paper and board materials heated at 60 to 100 °C (Wenzl and Lankmayr, 2002). Other substances were also detected in the headspace above the test samples but were not identified. Whilst transfer to foods was not investigated in these studies, the fact that they were shown 

One such study comparing headspace purge and trap GC-MS, odour tests and an electronic nose showed that the electronic nose could differentiate between unprinted boards and printed and lacquered boards by analysing the vapour phase of the heated boards (Heinio and Ahvenainen, 2002). Optimum differentiation of materials was achieved when test materials were heated at 60 °C for 20 minutes before sampling. Twenty board samples were studied including one unprinted board. Volatiles detected by headspace GC-MS included hexanal, hexane, heptane, toluene and branched hydrocarbons. The board samples were equilibrated overnight at room temperature in sealed headspace vials. 

Two of the substances detected, pentamethyl heptene and tetramethyloctene were considered as substances known to contribute to the odour of extrusion film coatings. The fact that these substances could transfer from the film to the gas phase supported the potential for these substances to give rise to odour problems in foodstuffs. They also impregnated a filter paper with octanal and placed it in the test cell in contact with paperboard laminated to various films including PE, PP, poly(ethylene terephthalate) (PET) and aluminium/PE (Al/PE) (with PE on the outer surface). They monitored transfer of octanal across the material held at 30 °C for 8-10 hours. Transfer was most rapid through uncoated paperboard. Octanal was shown to transfer across PE film laminated to the paperboard within ten minutes. There was no transfer of octanal through PP, Al/PE and PET over ten hours. 

---