Determination Methods Of Nitrite Content And Its Analysis In Leftover Food Samples

Purpose: A suitable method was selected through the comparison of the determination methods of nitrite.The content of nitrite in leftoverfood sampleswas obtained from the appropriate test method,and the trend of nitrite content in a period of time was found via analysis of the results.To some extent,the result changes people’s views on nitrite content in leftoverfood samples.Method: The determination methods of nitrite were reviewed.This paper introduces the methods of chemical analysis,optical analysis,chromatography,electro chemistry and so on.Also,the advantages and disadvantages of these methods are compared.Griess reagent colorimetric method was used combined with the reality to determine nitrite content in a cooked cabbage,a cooked carrots and a cooked beef,which were preserved 12 h,24h and 48 h at room temperature and at 4℃ respectively.Result:Griess reagent colorimetric method was carried out.The content of nitrite in the cooked cabbage was respectively 0.057mg/kg,0.089mg/kg,and 0.18mg/kg which was preserved 12 h,24h and 48 h at room temperature,and the average value was 0.11mg/kg.While at 4℃,the corresponding content of nitrite was 0.037mg/kg,0.057mg/kg,and 0.057mg/kg,and the average value was 0.050 mg/kg.When it comes to the cooked carrots,the content of nitrite was respectively 0.057 mg/kg,0.073mg/kg,and 0.10mg/kg which was preserved 12 h,24h and 48 h at room temperature,and the average value was 0.077mg/kg.While at 4℃,the corresponding content of nitrite was 0.057mg/kg,0.057mg/kg,and 0.073mg/kg,and the average value was 0.062mg/kg.The content of nitrite in a cooked beef was respectively 0.089mg/kg,0.087mg/kg,and 0.18mg/kg which was preserved 12 h,24h and 48 h at room temperature,and the average value was 0.12mg/kg.While at 4℃,the corresponding content of nitrite was 0.067mg/kg,0.089mg/kg,and 0.089mg/kg,and the average value was 0.082mg/kg.Conclusion: The nitrite content of all samples measured by Griess reagent colorimetric method was less than the national standard(Meat for 3mg/kg,vegetables for 4mg/kg).The content of nitrite in the cooked cabbage preserved at room temperature was 3 times the nitrite content of that preserved at 4℃ after 48 h.The content of nitrite in a cooked carrots was almost the same as that at room temperature and 4℃.The content of nitrite in a cooked beef preserved at room temperature was 2 times the nitrite content of that preserved at 4℃ after 48 h.Compared with room temperature,the nitrite content was lower in the dishes stored at 4℃.Although the nitrite content of the dishes will increase with the time,the total nitrite content is significantly lower than that of the leftovers preserved at room temperature.The risk of nitrite in leftoverfood samples may be negligible.