Milk and dairy products provide essential nutrients and are an important source of dietary energy, high-quality proteins and fats. Dairy fat was regarded as the most valuable component of milk, but there is a close relationship between the protein and fat content of milk – the more protein is there, the more fat is. Our system allows determining the content of total nitrogen by the Kjeldahl method. The protein content in dairy products is estimated by multiplying the determined nitrogen content by a nitrogen-to-protein conversion factor.