Abstract: Liquid chromatography-triple quadrupole tandem mass spectrometry (LC-MS/MS) was used to detect the migration of the primary aromatic amines 2,4-diaminotoluene (2,4-TDA) and 4,4’-diaminodiphenylmethane (4,4’-MDA) from polyamide/polypropylene (PA/CPP) retort pouches to acidic food simulants (4% acetic acid solution). In addition, different heat treatments and sterilization methods (pasteurization, steaming, boiling, high-temperature sterilization, and ultraviolet sterilization) were compared for their effects on the migration of both substances. The results showed that the limits of detection and the limits of quantifications for the migration of 2,4-TDA and 4,4’-MDA were both lower than 0.02 and 0.05 μg/kg, respectively, which meet the requirements of European Union standard for the limit of primary aromatic amines (PAAs). This study found that pasteurization, steaming, boiling, and high-temperature sterilization significantly promoted the migration of 2,4-TDA and 4,4’-MDA from PA/CPP retort pouches to 4% acetic acid solution in a temperature-dependent fashion (P < 0.05), which was not significantly affected by ultraviolet (UV) sterilization. According to the migration data, UV irradiation and pasteurization were relatively safe methods for the sterilization of foods packaged in retort pouches. In addition, steaming was a safer method than boiling for heating retort pouched foods. After 15 min of high-temperature sterilization at 121 ℃, the migration amounts of 4,4’-MDA from two commercial brands of PA/CPP retort pouches were 2.733 and 3.113 μg/kg, respectively, which were higher than the EU’s revision of the migration limit for individual PAAs (0.002 mg/kg) and could cause potential food safety risks. Hence, the impact of different heat treatment methods on the migration of PAAs from PA/CPP retort pouches and the safety of retort pouched foods is worthy of attention.

Key words: polyamide/cast polypropylene; primary aromatic amines; liquid chromatography-tandem mass spectrometry; food simulants; migration