QUICK METHODS TO CONTROL COMPLIANCE OF PLASTIC MATERIALS WITH FOOD-PACKAGING REGULATIONS

A general strategy is presented, aiming to provide plastics manufactur ers,food industries and enforcement laboratories with quick methods to check whether migration from materials for food contact will be accep table during the time of use. The strategy involves several steps, wit h increasing time demand and cost. Monitoring extraction kinetics allo ws both the optimization of the extraction time, and the selection of conditions where extraction is more severe than migration. The influen ce of the extracting solvent is discussed. It may give rise to specifi c non-extraction of some migrants, which may change the conclusions wh en the solvent is used in replacement of a fatty food simulant. Factor s ruling this effect at a given temperature are identified: the affini ty of the solvent with the migrant (selectivity), its ability to reach molecules entangled in the polymeric network (accessibility) and its interaction with the polymer (penetration). The kinetic parameters of the penetration of olive oil into polypropylene have been determined b y the determination of profiles of concentration.