Daily dietary intakes of nitrate, nitrite and volative N-nitrosamines in the Netherlands using the duplicate portion sampling technique.

In total, 201 duplicates of all foods and drinks sampled by adult volunteers during a 24-hour sampling period have been analyzed for nitrate, nitrite and volatile N-nitrosamines. For nitrate the mean daily intake was equivalent to 179 mg of potassium nitrate per 24 h, for nitrite this intake was equivalent to 4.2 mg of sodium nitrite per 24 h. The best estimate for the total daily fraction of salivary nitrite originating from dietary nitrate has been calculated as 6.3 mol%/24 h. For N-nitrosodimethylamine the mean daily intake was 0.38 microgram/24 h. The most important source of this nitrosamine contributing to the daily dietary intake was shown to be beer, which contributes 71% of the intake of an average consumer. Finally, attention has been drawn to the identification of N-nitroso-5-methyl-1,1-oxazolidine as an environmental nitrosamine present as an impurity in cutting fluids.