Why is there Cyanide in my Table Salt?

Yellow Prussiate of Soda (YPS, Na4[Fe(CN)6]·10H2O) is an approved anticaking agent in table salt. Given that it is a cyanide salt, its use as a food additive is surprising. In a recently accepted manuscript (Dorazio, S. J.; Brückner, C. J. Chem. Educ. 2015, accepted for publication) we highlight recent reports by Bode et al. (Cryst. Growth Des. 2012, 12, 1919. and  ibid. 5889.) on the mode of action of sub-monoatomic layers of YPS on NaCl crystals to act as an anticaking agent through nucleation inhibition . The molecular-level explanation reinforces the notion of how structure and charge affect the properties of matter. In addition, we report a simple naked eye analytical method of detecting YPS on store-bought table salt in the form of the pigment Prussian Blue (Fe4[Fe(CN)6]3·xH2O).