N-nitrosodimethylamine in German beer

Abstract

A total of 514 beer samples (called ‘first samples’), produced in Baden-Württemberg, FRG, between October and December 1987, were analysed for their N-nitrosodimethylamine (NDMA) content. In 302 of the samples NDMA was not detected (<0.2 μg/kg), 191 contained indeterminable traces of NDMA (0.2–<0.5 μg/kg) and 21 samples showed NDMA contents of 0.5 μg/kg to 1.7 μg/kg. The technical threshold value of 0.5 μg/kg was exceeded by 14 samples. No significant differences in the NDMA content were observed between the different beer types, but beers with a higher malt extract content (strong beer) showed slightly increased average NDMA content. Top fermented pale ale produced from wheat malt showed, as expected, the lowest average NDMA content. For those samples containing greater than 0.5 μg/kg NDMA an additional sample of the same beer type, but produced some months later (called the ‘second sample’), was analysed. The highest content of NDMA found in the second samples was 3.2 μg/kg. The average NDMA content of the 514 first samples was 0.16 μg/kg and the average daily intake was calculated as 0.1 μg for men and 0.03 μg for women. Individual daily intake of NDMA, depending on the amount of beer consumed and the beer type, may reach up to 10 μg/person/day.