FOR the feeding of babies, everyone agrees that “breast is best”. It is not, however, always convenient. Textile workers in Bangladesh, who are mostly women, are entitled to four months’ maternity leave. Once this is over, they often end up parking their children with relatives when they are at work. Those with refrigerators at home can use breast pumps to express milk before they go on shift, and leave it behind to chill. But fridges are expensive, and many do not own one. Unchilled milk goes off within a couple of hours so the inevitable outcome for fridgeless mothers and their babies is the use of infant formula.

A chance meeting in a coffee shop in Dhaka may, though, have helped with this problem. It was between Sabrina Rasheed (pictured above, right), a child-nutrition expert at the International Centre for Diarrhoeal Disease Research in Bangladesh, and three Canadian students. Two, Scott Genin and Jayesh Srivastava, are engineers. The third, Micaela Langille-Collins, is a trainee doctor. The upshot of the encounter was that Dr Rasheed gave the students the job of designing a low-cost, low-tech way of keeping mothers’ milk healthy in Bangladesh’s tropical climate, without resorting to refrigeration.

The device the trio came up with, shown in the picture, is a cheap pasteurisation machine based on a food warmer of the sort used in canteens. Instead of food, the warmer’s vessels are filled with paraffin wax, which is liquefied by the heat. Bottles containing expressed milk, held in bags made of silicon-coated nylon, are hung from a plate and bathed in the wax, which is then heated further. A thermometer in the wax registers the temperature, and once that reaches 72.5°C—the level required for pasteurisation—a timer is started. After 15 seconds this sets off an alarm to indicate that the milk has been cooked enough to kill hostile bacteria, and the bottles are removed and allowed to cool.

Thus pasteurised, microbiological tests show, the milk’s shelf life at local room temperatures increases from two hours to somewhere between six and eight. This means no refrigeration is required and relatives looking after babies need collect expressed milk from the factory, where the machine is located, only once a day. The pasteurised milk also retains most of its nutritional value.

With the aid of ten donated breast pumps, Ms Langille-Collins and her colleagues tested their invention at the Interfab Shirt Manufacturing workshop, north of Dhaka. To start with, mothers employed there were suspicious, says Aliya Madrasha, head of human resources at the factory. That changed, though, when they came to understand both the convenience of the system, and the economy of no longer having to buy formula milk.

The new machine is also a hit with the factory’s management. Expressing their milk at the beginning of a shift means women with babies suffer less discomfort during the day, and so are more productive. Absenteeism among mothers has also dropped, from five days a month to one. The biggest benefit, though, according to Ahasan Kabir Khan, the factory’s owner, is the retention of skilled staff who might otherwise leave to nurse their children.

Mr Khan is so impressed that he now wants to put pasteurisation machines in all his factories. Other factory owners, too, are asking for the machines. Dr Rasheed and Ms Langille-Collins are therefore developing a commercial version of the machine, in collaboration with 10xBeta, a firm in New York. If their patent application is approved, they plan to lease the devices to firms all over Bangladesh and then, subsequently, to people in other poor countries all around the world.