This simple milk processing technique can preserve milk safely for one full year. Hence it is very useful in providing additional family income to rural women through self employment.
The fresh milk is heated to a temperature of 600 C. Sugar and other flavours are added before being transferred to milk bottles. The bottles have to be thoroughly cleaned with a detergent or sand and rinsed well in hot water. Milk should be filled leaving a gap of 5 cms from the mouth of the bottle. The bottles are made air tight with crown corks using a manually operated machine. After checking for leakages they are placed in an autoclave or domestic pressure cooker. The autoclave or cooker is heated to 1100 C - 1150 C under 6.5 kg pressure for 4 - 5 minutes. The autoclave is then removed from the fire and kept on the floor for cooling. The bottles are removed and stored on a shelf in a cool place. These bottles should be checked after every 2 - 3 days. If any bottle shows signs of contamination it should be removed from the shelf (precipitation or change in colour). The properly sterilized milk remains usable for about a year under ordinary conditions. The remaining bottles should then be packed carefully so that the corks do not become loose during transportation and be exposed to contamination.
Centre for Rural Development and Appropriate Technology (CRDAT), Indian Institute Of Technology (I.I.T.), Hauz Khas, New Delhi - 110 016