Initially, cream was separated and retained for buttermaking and the fresh skim milk was returned to the milk producers. Casein and casein products as well as lactose and dried milk were prepared. In countries with commercial dairying these processes are carried out in large-capacity processing plants. In Africa, milk is produced in most agricultural production systems. It is either sold fresh, consumed as fermented milk or manufactured into products such as butter, ghee and cheese.
Sour milk is the most common product, and milk is usually soured before further processing.
It is important, therefore, to consider these processes and look to possible technological interventions at this level when considering dairy development in the rural sector. Farmers in many African countries produce sour milk, butter and cottage cheese for home consumption and sale. The Maasai in Kenya make ghee from sour milk. Fermented milks are made throughout sub-Saharan Africa, and concentrated fermented milks are made in some parts of the continent. While the processes used have not been subject to extensive scientific investigation, they appear to be effective methods of converting milk into stable marketable products and have long been used for processing surplus milk.