Changes of sodium nitrate, nitrite, and N-nitrosodiethylamine during in vitro human digestion

- Amounts of nitrate, nitrite and NDEA decreased during in vitro digestion.
- E. coli dramatically reduced nitrite concentration during in vitro digestion.
- L. casei effectively reduced nitrate concentration during in vitro digestion.
- Amount of NDEA effectively reduced by both E. coli and L. casei.
- This is the first report that human digestion can reduce these compounds.

This study aimed to determine the changes in sodium nitrate, sodium nitrite, and N-nitrosodiethylamine (NDEA) during in vitro human digestion, and the effect of enterobacteria on the changes in these compounds. The concentrations of nitrate, nitrite, and NDEA were significantly reduced from 150, 150, and 1 ppm to 42.8, 63.2, and 0.85 ppm, respectively, during in vitro human digestion (p < 0.05). The enterobacteria Escherichia coli and Lactobacillus casei reduced the amount of these compounds present during in vitro human digestion. This study is the first to report that E. coli can dramatically reduce the amount of nitrite during in vitro human digestion and this may be due to the effect of nitrite reductase present in E. coli. We therefore conclude that the amounts of potentially harmful substances and their toxicity can be decreased during human digestion.