Nitrate and nitrite content of vegetables, fruits, grains, legumes, dairy products, meats and processed meats

The aim of this study was to investigate the contents of nitrate/nitrite in frequently consumed food items among Iranians. Stratified random sampling was conducted seasonally from November 2014 through January 2016 for samples collected from the main municipal markets of Tehran. To determine the nitrate/nitrite contents of foods, spectrophotometric methods, developed by International Organization for Standardization (ISO), were used. Method limit of detection (LOD) was 0.61 mg 100 g−1 and 0.10 mg 100 g−1, for nitrate and nitrite, respectively, and method limit of quantification (LOQ) was 1.86 mg 100 g−1 and 0.16 mg 100 g−1 for nitrate and nitrite, respectively. A relatively high nitrate concentration was observed in breads (∼50.0 mg 100 g−1). Mean ranges of nitrate and nitrite in fruits were 7.50–46.8 mg 100 g−1 and 0.15–0.71 mg 100 g−1, respectively. Vegetables with the highest nitrate concentrations included radish (625 mg 100 g−1), beetroot (495 mg 100 g−1), tarragon (424 mg 100 g−1), lettuce (365 mg 100 g−1), mint (279 mg 100 g−1), and celery (261 mg 100 g−1). Nitrite content of vegetables ranged 0.21–0.74 mg 100 g−1. In dairy products, mean nitrite and nitrate content ranged 0.14–0.45 mg 100 g−1 and 1.26–5.75 mg 100 g−1. Mean nitrate and nitrite concentrations in meats and processed meats were 5.56–19.4 mg 100 g−1 and 2.93–13.9 mg 100 g−1, respectively. This database could provide opportunities to quantify nitrate and nitrite exposure of Iranians and to evaluate risk-benefit of nitrate-nitrite exposure.