Garima Rakesh Mishra | The Indian Express
February 23, 2017 1:50 am

The near-quadrupling of milk procurement by dairy cooperatives in Gujarat over the last 15 years — from an average of 45 lakh litres to about 170 lakh litres per day — has been attributed no less to a single factor: 24-hour power in rural areas, including guaranteed three-phase supply for eight hours, enabling village-level societies to install bulk milk coolers (BMC). These, with capacities ranging from 1,000 to 10,000 litres, chill the milk to around 4 degrees celsius at the primary collection point itself, inhibiting microbial growth that can lead to undesirable quality/taste changes and expedite spoilage. 

But maintaining the freshness of raw milk sourced from farmers isn’t all that the BMCs have done.

In the pre-BMC era, the milk collected by the society had to reach the dairy plant by 8:30 am or so, before day temperatures rose. It required procurement to start by 6 am and farmers undertaking milking at least an hour earlier, so as to not miss the tanker. The sheer need to hurry through the process, moreover, limited the number of animals that could be milked. With BMCs, the milk was chilled at source and remained fresh, which gave farmers the flexibility to deliver even at 9 am. They could now afford to expand their herd size and supply more milk.

Today, an estimated 80 per cent of milk collected by Gujarat’s dairy unions comes through BMCs and it is not difficult to see the link between these and higher procurement volumes.

Not every state, unfortunately though, is Gujarat — where farmers have assured electricity supply allowing milk to be chilled not very long after it has left the udders of cows or buffaloes. In much of rural India, power supply is irregular, which means even BMCs cannot do without the backup of diesel generators.

This is where an innovation by Promethean Power Systems, a Pune-based company founded by two men from Boston has made a difference. In 2011, Sorin Grama and Sam White built the final prototype of a Rapid Milk Chiller (RMC) based on a proprietary Thermal Storage System (TSS) technology. At the heart of it lay a thermal battery, which drew and stored electricity from the grid as and when available. This stored energy it then released to rapidly chill the milk collected from farmers at ambient temperatures — say, 35 degrees — to 4 degrees Celsius.

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