N-nitrosamines in Chinese foods.

A total of 695 different Chinese foods and ten malt samples were analysed, using gas chromatography-thermal energy analysis, for the possible presence of volatile N-nitrosamines. N-Nitrosodimethylamine (NDMA) was found in 146 of 176 beers tested at concentrations ranging from 0.1 to 6 ppb. NDMA was also detected in 201 of 271 meat products tested at concentrations ranging from 0.1 to 7.4 ppb. High levels of NDMA, up to 131.5 ppb, were detected in some seafoods and were further confirmed by gas chromatography-mass spectrometry. Milk products were found to contain less than 0.1-3.6 ppb NPYR, less than 0.1-5.7 ppb NDMA and less than 0.1-0.7 ppb NPIP, while in flavourings the nitrosamine concentrations were less than 0.1-10.3 ppb NPYR, less than 0.1-3.6 ppb NDMA and less than 0.1-0.9 ppb NPIP. Pickled vegetables contained less than 0.1-25.5 ppb NPYR and less than 0.1-15 ppb NDMA.