In the study, analyses were run in duplicate for all samples and
then the average values for all samples were considered for
calculation of nitrate/nitrite content of foods. Linear regressions of
the mean values of the absorbance at 538 nm for each standard
curves minus the blank values were used to determine the total
nitrate/nitrite and nitrite concentrations in the samples; the
respective formulas for calculation of nitrate/nitrite contents of
different food groups are provided in