Bulk milk cooling unit is used to cool raw milk at the village level co-operative milk societies from the ambient temperature to 4 degree Celsius in conformity to specified ISO standard .

The cooling tank is used for cooling the milk immediately after milking to conserve quality of milk and check growth of micro-organisms. It is intended for daily collection of milk. It is a hygienic container built to sanitary standards, which besides cooling also serves as buffer storage prior to transfer of milk for onward transportation and further processing.

The milking system has been configured such that volume of each milking is as under:
i) Milking in the morning (up to 10 AM ) - 50 %
ii) Milking in the evening - 50 %

The agitator provided in the cooling tank works intermittently and at a very gentle speed to avoid damage to the milk fat globules.

The best alternative to present collection system of milk is cooling of milk immediately after milking by bulk cooling tanks. The usage of such tanks has become popular in the recent past because it not only helps in increasing the shelf life of milk but also provides a systematic and simple way, to ensure procurement of more milk by covering untapped areas for milk procurement.

As per the latest Draft Codex International Code of Hygienic Practice for Milk and Milk Products from Codex Secretariat, if milk is not processed within two hours of milking, it is required to be cooled to a temperature below 7deg celsius. Therefore, the dairies who have to market their milk and milk products in international market shall have to comply with the Codex International Code of Hygienic Practice and cold chain will become a must for them. Initial capital investment pays back in the long run, as the system eliminates use of milk cans, milk sourage and reduction in transportation costs..

Typical rural milk chilling and collection system