The status of fluoride added to bovine milk

The use of bovine milk as a carrier for fluoride has been advocated as a prophylactic measure. The effect of the addition of sodium fluoride to cold milk, up to 1000 ppm, was examined by particle micro electrophoresis, centrifugation, and dialysis.
The fluoride had little effect on the electrokinetic potential, and no sedimentation calcium fluoride occurred. Even with centrifugation at 30 000 g , the bulk of the fluoride remained in solution. Dialysis showed that the fluoride could easily be removed, and that the eluent contained fluoride in the ionic (free) form.
The addition of fluoride to calcium phosphate free (CPF, milk showed that the bulk of the fluoride remained with the protein, even after addition of excess calcium chloride. Thus the fluoride does not affect the stability of milk and the element forms a reversible ionic complex. The evidence suggests that it is held in solution by the smaller milk proteins.