Milk Chiller Tech to Aid Poor Farmers

Each year, millions of gallons of milk go to waste because farmers can’t get it chilled quickly enough. It’s a common problem in countries like Uganda and India. A milk chiller, as it’s called, requires power, and lots of it. Which means, of course, a connection to the electricity grid and and usually a diesel generator as a back-up. It’s a set-up that often too expensive for many farmers and dairies in the developing world. The World’s Clark Boyd writes about efforts to develop tech to help these farmers and dairies in his latest column for BBC Future.

William Kisaalita has cold milk on his mind.

The tissue engineer runs a program at the University of Georgia in the US that develops new technologies to help farmers in his native Uganda, where he grew up on a farm.

“I’ve always had an interest in doing something for small farmers,” Kisaalita tells me. “They are my aunts and uncles, my brothers and sisters. No one develops tech to help them, but I feel that there is room to create products that improve their profitability.”

Kisaalita has worked on a number of such problems over the past decade, including a low-cost nutcracker for farmers in Morocco and a solar-powered incubator for guinea fowl in Burkina Faso. But now he has turned his attention to milk producers in his home country.

Many small-scale Ugandan farmers own a few cows, which are milked twice a day to sell locally or to larger dairies. But here’s the thing – for it to stay fresh, the milk has to be cooled – easier said than done in areas with intermittent or no electricity. “I’ve seen farmers pour their milk away at the end of the day,” Kisaalita says. “Sometimes as much as half of it.” And when sour milk is poured away, so too are profits and a valuable source of nutrition.

The United Nations, in fact, estimates that 27% of all milk in Uganda goes to waste, much of it due to spoilage. The UN says that loss costs Ugandan farmers more than $20m a year. The yearly losses are similar for neighbouring Kenya and Tanzania.

So Kisaalita and his students began building a small-scale milk chiller that could hold 20 litres of the white stuff. Traditionally, big dairy machines have an outer and inner tank, with insulation in the space between. Compressors, condensers and refrigerants are pumped through the system to rapidly chill the milk and keep it cool. It’s a system that requires a constant electrical power, either from the grid or from a diesel generator back-up. Read more>>