[Storage Stability of Nitrite in Nitrite Analysis of Meat Products].

For the analysis of nitrite ions in food, the stabilities of nitrite ions in meat products and their standard solutions were evaluated. Nitrite is easily oxidized or reduced; hence, products with standard solutions or colour retention agent must be carefully handled. To assess the stability and decreasing trend of nitrite, we examined the storage stability of standard solutions using calibration curves, the time course of nitrite in chopped meat products stored under different conditions, and the time course of nitrite in the sample solutions. Regarding calibration curves, the storage stability was determined for standard solutions that were prepared with ultrapure water at concentrations of 0.025 and 0.4 μg/mL and were stored at 5℃ for one year. The results revealed no changes in concentration of any solution over time, suggesting that no readjustments to the standard solution concentration were necessary before testing until one year after their preparation. Time course of nitrite in chopped meat products stored under different conditions showed a significant decrease in nitrite in refrigerated storage (5℃), whereas stability of nitrite was maintained for up to 1 day in frozen storage (-20℃) and for 14 days in frozen storage (-40℃). The time course of nitrite in the sample solutions showed that the quantitative values of nitrite in the extract remained unchanged within one week of extraction for the meat products tested in the study.