Article Title

Investigation of the nitrate and nitrite contents in milk and milk powder in Taiwan


Cow milk is one of the most important nutrition sources besides breast milk for infants and babies; therefore the detection of nitrate and nitrite in milk is of great importance to the health of infants and babies. Traditional colorimetric method for the determination of the nitrate and nitrite concentrations in food is very tedious. In the present study, 100 samples of milk and milk powder were analyzed by ion chromatography to detect nitrate and nitrite simultaneously without tedious preparation steps. The limit of detection (LOD) for nitrate is 0.33 ppm and the LOD for nitrite 0.07 ppm. The measured nitrate concentration in milk ranged from 0.3-417.7 ppm with an average concentration of 92.7 ppm. The nitrite concentration in all milk samples were below the detection limit. The survey information was as the following: (1) the average nitrate concentration of colostrums fortified milk ranged from 14.1 to 136 ppm. (2) the average nitrate concentration of whey fortified milk ranged from 42.6 to 242.8 ppm. (3) the average nitrate concentration of ordinary milk ranged from 57.9 to 157.6 ppm. The dietary intake of nitrate from milk and milk products in Taiwanese adults and children were estimated. All the nitrate exposure levels calculated with the measured results for the different age groups were less than the acceptable daily intake (ADI) of 3.7 mg/ kg body weight per day suggested by WHO. Finally the health effect of nitrate and nitrite in foods was discussed.

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