Quality control in the production of fluoridated food grade salt

Fluoridated food grade salt has been manufactured in Switzerland for 50 years. Since correct dosing is important not only for effective caries prophylaxis but also in order to guarantee food safety, the production of fluoridated salt must be accurately monitored. The authorities do not impose any specific requirements as regards the purity of the fluoride compounds that are used, nor the homogeneity or dosing accuracy that should be attained during the manufacture of fluoridated salt. The quality requirements to be observed and the means by which these standards are to be ensured must largely be determined by the producer himself as part of the "self-monitoring" that is stipulated by the law. Depending on whether fluoridated salt is manufactured in a continuous or discontinuous process and on whether the fluoride is added as a solution or in solid form, a plant-specific testing plan must be drawn up for the implementation of quality monitoring. On the basis of statutory requirements, a food manufacturer must subject all the processes which he carries out to a risk analysis (HACCP study). Monitoring of the dosing of fluoride must be classified as a Critical Control Point (CCP). Three well-established testing methods which have been validated in ring tests are available to determine the fluoride content in food grade salt (a potentiometric, an ion-chromatographic and a photometric method). In practice, the potentiometric method has proven to be a simple, accurate and comparably low-priced process and is widely used.