An investigation of the levels ofN‐nitrosodimethylamine, apparent totalN‐nitroso compounds and nitrate in beer

Abstract

Over 170 retail samples of beer have been analysed for N‐nitrosodimethylamine (NDMA), apparent total N‐nitroso compounds (ATNC) and nitrate. Levels of NDMA ranged from below 0.1 up to 1.2 μg/kg with a mean of 0.2 μg/kg. ATNC was detected in 42% of the samples in concentrations of up to 569 μg(N‐NO)/kg. The levels of nitrate ranged from less than 0.2 up to 143 mg/kg with a mean of 16.8 mg/kg. There was no correlation between the amounts of NDMA and ATNC found in the retail beers. Samples taken during the course of fermentation showed that NDMA was unaffected by the bacterial reduction of nitrate which causes ATNC formation. HPLC studies using a photolysis/chemiluminescence detector revealed that the ATNC in beer are highly polar species of as yet unknown identity.