Studies on functional barriers to migration. 3. Migration of benzophenone and model ink components from cartonboard to food during frozen storage andmicrowave heating

Studies of the migration of benzophenone from inks and of model ink compone nts incorporated deliberately into cartonboard have been carried out a low temperature and during microwave heating. Benzophenone was found in the pac kaging of four of seven frozen foods examined and this was attributed to it s use as a photoinitiator for UV-curved ink. Benzophenone was found to migr ate to the packaged food even from polyethylene-coated board, and this was attributed in part to the fact that polyethylene is rather permeable to low molecular weight substances and is not a good barrier to migration. Additi onal studies were conducted with two other frozen foods by incorporating mo del ink components into their cartonboard packaging. The substances were be nzophenone, benzylbutyl phthalate, butyl benzoate, chlorodecane and dimethy l phthalate. Migration was readily detected after storing the food at -20 d egrees C for 1 week in the impregnated cartonboard. Migration levels in the food increased only slowly thereafter, up to 1 year, except for the most v olatile substances used. Subsequent heating of the frozen food using a micr owave oven decreased the concentration of some migrants by volatilization, but increased the concentration of other, less volatile substances by heat- accelerated migration. It is concluded that for inks used to print food con tact materials, if the content of low molecular weight volatiles is control led and if transfer of higher molecular weight components via set-off is co ntrolled also, then migration levels could be kept low in these conditions. Copyright (C) 2000 Crown Copyright.