WHAT IS THE COMPOSITION AND QUALITY OF WISCONSIN MILK ? Milk Composition

1 What is the ideal milk composition for cheese manufacture? How close is Wisconsin milk to that ideal, and how does it compare with milk from other leading dairy states? What can Wisconsin's dairy farmers and cheese processors do to ensure that milk produced in the state improves the state's cheese industry from farm to wholesale product? These questions are addressed in this report, which supports Rethinking Dairyland leaflet No. 7. The ideal milk for making a whole milk cheese, e.g. Cheddar, would contain 14-15 percent total solids and have a casein-to-fat ratio of about 0.7. This would typically be milk with about 4.2 percent fat and about 3.6 percent true protein. Few, if any, cows produce milk of this composition. So cheese makers standardize their milk using a variety of processes. Fat content may be reduced through cream separation. Solids content may be increased through vacuum pasteurization or by adding additional nonfat milk solids to the raw milk in the form of condensed skim milk, nonfat dry milk or ultrafiltered milk concentrate. Basically, the two main ingredients of milk that a cheese maker needs are casein and fat. The amount of fat that can be used in a cheese make procedure is limited by the amount of casein present to hold the fat in a stable system. Thus, the casein to fat ratio is a critical one determining the cheese making potential of a milk supply. The final composition of a cheese will dictate what amount of casein and fat are required to make that cheese. Ideal casein to fat ratios (based on recommendations from the WI Center for Dairy Research) for some varieties of cheese are shown in Table 1.