Grades and Methods of Analysis of Dry Skim Milk

Abstract

The increased use of dry skim milk in the food industries has created a need for its proper classification by grades, so that the grade name may be taken as an index of quality. Formerly the quality of this product has been appraised by direct observation of its physical properties, by the results of selected laboratory determinations, or by a combination of both. Grading practices of the past have not been uniform due to the following: variation in the criteria accepted as a basis for grading; lack of adequate terminology to be applied to characteristics of quality; variations in laboratory practice; and undefined expression of the limits of probable errors in analysis. The work of the Standards Committee of the American Dry Milk Institute consisted of collaborative work on laboratory technic, selection of the most suitable methods of analysis, the examination of a large number of samples and the correlation of the results of inspection and laboratory determinations with the more universally accepted trade demands of quality. Three grades of quality have been established and these in turn are applied to each of three divisions named according to the method of their manufacture spray, vacuum drum, and roller. A single standard for evaluating the quality of all dry skim milk would be simpler but owing to a variation in the relation of solubility to the several industrial applications of this product, the above division is deemed necessary at this time. Each of these divisions is subdivided into extra, standard, and third grade. It is not intended that classification under the