Levels and Matagenic Activity of N-Nitrosodimethylamine in Fermented Fishes

Abstract

Partially purified N-nitrosodimethylamine (NDMA) from 88 samples of uncooked fermented fish extracts obtaining from three different geographical regions of Thailand was quantitatively investigated using absorption spectrophotometric technique. Only about 7.56% of total specimens observed to be negative for this particular toxic compound. The NDMA levels of positive batches were in the range of 32 - 638 parts per billion (ppb), 28 – 352 ppb, and 42 - 1,228 ppb for the samples obtained from Northern, Central and Northeastern region of Thailand, respectively. The in vitro mutagenesis activity of chemically occurring NDMA in all positive hatches were also detected by using two different strains of Salmonella typhinturiunt (TA 98 and TA 100) via preincubation with a rat liver microsomal enzyme system (S-9 Mix). The mutation was shown base-pair substitution. A linear dose-response relationship between mutagenicity and the extract concentration was investigated. The mutagenicity of fermented fish extracts obtained from 3 regions also shows correlation with the levels of NDMA.