Formation of N-nitroso compounds under simulated gastric conditions from Kashmir foodstuffs

Abstract

Several foodstuffs and teas from an area of high esophageal cancer risk in Kashmir (India) were studied under simulated gastric conditions with a realistic nitrite concentration for the formation of N-nitroso compounds. N-Nitrosodimethylamine (NDMA), N-nitrosoproline (NPRO), N-nitrosothiazolidine-4-carboxylic acid (NTCA) and N-nitrosopipecolic acid (NPIC) were the main products in different foods. Significant amounts of NDMA were formed from dried fish (20 micrograms/kg), dried and pickled vegetables (35.6 micrograms/kg and 7.3 micrograms/kg), locally grown Brassica oleracea ('Hak') leaves (69.9 micrograms/kg), and the traditional tea 'Kehwa' (9.2 micrograms/kg). The highest level of NTCA was formed in smoked fish (3294 micrograms/kg). 'Salted tea' prepared according to local method formed considerable amounts of NPRO (360 micrograms/kg) and NPIC (5870 micrograms/kg) along with 3 yet unidentified non-volatile N-nitroso compounds. High values of 4315 micrograms/kg NPIC were also obtained following nitrosation of red chillies and mixed spice cake ('Wur') under simulated gastric conditions. These results suggest the possibility of an appreciable endogenous formation of N-nitroso compounds from local foods in Kashmir.