In the reported study were determined the isotherms and the kinetics of the process of adsorbing water vapour by mixtures of powder foods and their agglomerates produced using a method of repeated wetting in a fluidised bed that was pneumatically or mechanically generated. The mixtures were made of products in the form of powders: whole milk powder, powdered sugar, rice groats and strawberry powder. The mixtures had a composition pattern of the commercially available powdered nutrients for children. The effect of wet agglomeration in a fluidised bed on the water vapour adsorption by multi-component food powders depended on its character. The effect of changes, aimed at decreasing the adsorption capacity of water steam by agglomerates, depended first of all on their compositions and to a lower extent on their structure connected with the method of agglomeration and kind of wetting liquid used in the process.