Operators in industry maintain that milk powders standardised with permeate are more sticky when they are dried than powders standardised with pure lactose solutions. This work uses the particle gun to determine whether or not any significant difference could be found between powders standardised by the two different streams.

The results showed that there was no significant difference in stickiness behaviour, as determined by the particle gun and the fluid bed techniques, between the two solutions used for standardisation. The bulk composition and surface composition was also shown to be the same, except for the surface composition of lactose in Whole Milk Powder, which was significantly higher for the pure lactose standardisation solution compared to the permeate solution and the unstandardised whole milk powder. It has been concluded that the additional salts in the permeate are insufficient to affect the stickiness properties of the powders, and the operators experience cannot be substantiated.