Sampling of bread for added sodium as determined by flame photometry

Sodium content in bread is a growing interest in public health. This study was undertaken to evaluate the role of sampling in the dispersion of salt content in bread. Ten brands of bread representing the consumed types were collected from the largest retail places in Portugal. Their sodium and potassium contents were determined using flame photometry. The ratio sodium/potassium was used as an indicator of salinity. Sodium content varied from 490 ± 21 to 724 ± 9/100 g of white bread. Data from uncertainty budgets demonstrated that sampling is the dominant contributor (>55%). According to our results for sodium in bread, to pool samples from different sampling points can disguise the heterogeneity of the results. Therefore, the importance of the number of primary sample units and of the identification of sampling points is highlighted. This provides the necessary information to the users of Food Composition Databanks who wish to have an overview of the parameters, which influence the estimation of sodium intake values, which may affect the diet-disease relationship.