The temperature of migration solutions on the preparation of a test solution for migration tests of food-contact products was monitored using a temperature data logger under several heating conditions. Temperature transitions of the solutions heated via four types of water baths set at 60ºC were similar, and the temperature increased with time reaching 60ºC ± 2ºC after heating for 15 min. On the other hand, the temperature increase of the solutions heated using drying ovens was slower than that heated by water baths, and in some cases, the temperature did not reach 60ºC ± 2ºC. Furthermore, the temperature differed according to the drying ovens and the position in the oven. The temperature of the migration solutions by the total immersion method performed at 60ºC for 30 min using water baths and drying ovens temporarily decreased to 56.5ºC–58.0ºC after applying the samples into the solution. Further, the temperature increased rapidly and was maintained at 60ºC ± 2ºC using a water bath set at 60ºC. The temperature increase of the solutions heated using drying ovens set at 60ºC was slower and reached 60ºC ± 2ºC after heating for more than 15 min. However, it was maintained at 60ºC ± 2ºC using a drying oven set at 65ºC, and it was also maintained using a drying oven set at 60ºC when the migration solution preheated at 65ºC was used. The temperature of the migration solution by the total immersion method performed at 95ºC also temporarily decreased to 85.8ºC–90.9ºC after applying the samples into the solution. However, the temperature was maintained at 95ºC ± 5ºC using a water bath set at 95ºC and drying ovens set at 105ºC, 110ºC, and 115ºC. On the other hand, the temperature of the migration solution by the single surface testing performed at 60ºC decreased considerably to 44.4ºC–51.3ºC upon pouring the migration solution into a single surface migration vessel and did not reach 60ºC ± 2ºC after heating for more than 20 min. However, by heating the single surface migration vessel at 60ºC before pouring the migration solution into the vessel, the temperature slightly decreased to 59.1ºC–59.7ºC and was maintained at 60ºC ± 2ºC using a water bath set at 60ºC and a drying oven set at 70ºC. The temperature of the migration solution using the single surface testing performed at 95ºC also decreased to 89.2ºC–90.1ºC upon pouring the migration solution into the vessel with preliminary heating at 95ºC. Subsequently, the temperature was maintained at 95ºC ± 5ºC using a water bath set at 95ºC or a drying oven set at 115ºC. Migration tests into 4% acetic acid by the total immersion method were performed using two rubber gloves, and the resulting total evaporation residue levels and the migration levels of zinc and calcium were compared under several heating conditions. No significant differences in their migration levels were observed in the cases where the migration solution temperatures were maintained within 60ºC ± 2ºC or 95ºC ± 5ºC.
