Nitrite level of pickled vegetables in Northeast China

Abstract

Nitrite is commonly present in pickled vegetables. Nitrite has been proven to have adverse effects on health, including changing the normal form of hemoglobin and the formation of carcinogenic nitrosamines. The aim of our study was to determine the levels of nitrite in pickled vegetable samples consumed in Harbin, China. In this study, 218 samples of pickled turnip (PT) (n = 42, packaged (PK) = 19; unpackaged (UPK) = 23), pickled tuber mustard (PTM) (n = 44, PK = 23; UPK = 21), pickled cucumber (PCC) (n = 48, PK = 25; UPK = 23), and pickled cabbage (PCB) (n = 84, PK = 39; UPK = 45) were analyzed between October 2011 and December 2011, using colorimetric nitrite assay based on the Griess reaction. A nitrite level of <5 mg/kg was normally predominant in 147 (67%) samples of the investigated pickled vegetables, ranging from 0.01 mg/kg to 42.03 mg/kg, while a nitrite level of >20 mg/kg was detected in 9 (4%) samples. The overall nitrite content was 4.02 ± 0.62 mg/kg for PT, 4.52 ± 1.07 mg/kg for PTM, 3.91 ± 0.69 mg/kg for PCC, and 4.86 ± 0.80 mg/kg for PCB. The content of nitrite in unpackaged pickled vegetables (PT, 5.47 ± 0.89; PTM, 6.84 ± 2.02; PCC, 5.32 ± 1.27; PCB, 6.41 ± 1.28; and total, 6.08 ± 0.71 mg/kg) was significantly higher than those in packaged products (PT, 2.68 ± 0.72; PTM, 2.30 ± 0.55; PCC, 2.62 ± 0.54; PCB, 3.08 ± 0.81; and total, 2.73 ± 0.36 mg/kg) (P < 0.05). The variance in the concentration of nitrite in the pickled vegetables probably resulted from differences in quality, processing technique, and storage condition of the pickled vegetables. Our results indicated that, in China, low level nitrite is widely present in pickled vegetables. It is therefore important to assess the content of nitrite in pickled vegetables in China.