The main way for recognizing packages is dividing them to hard, semi-rigid and rigid. The use of semi- rigid packaging for ready- to eat foods increases day by day. The packages which used in this study belong to this kind of packaging that made from 2 main layer; Aluminum and polypropylene, a kind of plastics. For improving the function of these plastics during process, forming and even use of them as food packaging, different kind of additives such as antioxidants, stabilizers, lubricants, antistatic substances and so on are added to them. But these days the safety of these packages especially due to the migration of additives from them is in doubt. Migration is studied in two aspects: Global or overall migration which is the amount of substances transfer from packages to food (include recognized and nonrecognized substances). According to EU if the overall migration is lower than 10 mg/dm 2 or 60 mg/kg of food, the package will not have safety concern. But the migrated substances may be very harmful. So the overall migration cannot assure the safety of packages by itself. Specific migration is the measuring the transfer of certain and recognized substance from packages to food. Measuring the overall migration is only possible in stimulants. Ethanol 10%, acetic acid 3 and extra deionized water as stimulants were used for this purpose. Packages in 6 replications were filled with stimulants and got sterile. After that the overall migration were measured with gravimetric method. For all 3 simulants the amount of migration were lower than EU limit. In this study since the base of these packages is Aluminum and it is considered as the element responsible for neurotic diseases especially Alzheimer, so it is chosen as specific migration substance. As the pH level of stew is between 2 EU stimulants, In this work distilled water and 3% acetic acid as stimulants, were processed exactly the same as chicken stews. The migration of aluminum in stew and stimulants was determined right after thermal process and during storage at 45°C by ICP_OES. Also the content of Al in chicken stew before sterilization was measured. From results, It was determined that aluminum migration in water was very low and the migration in chicken stew was more than stimulants. The effect of time in amount of migration was very pronounced. Regarding the suggested provisional tolerable daily intake of 1 mg Al/kg body weight per day of the FAO/WHO Expert Committee on Food Additives, Al leaching from semi- rigid Al- based packages may add low doses of Al into diet but the determined amount for stored packages may be risky for children and teenagers.