When iron comes in contact with potassium iodate, they react. The iodine evaporates and the iron forms compounds that are less easily absorbed by the body. The salt darkens and takes on a metallic taste – hardly something someone would want to sprinkle on food.
Mannar learned all of this the hard way. In 1993, he walked into the office of Levente Diosady, a food engineering professor at the University of Toronto specializing in the processing of edible oilseeds, and told him about the idea of DFS. “He said, ‘It should be pretty easy – can we do some testing? », Diosady remembers. “I said, ‘Yes, we can do some testing, but it probably won’t be that easy.’” The two received a small grant from a newly formed group called the Micronutrient Initiative to explore the technical side of the creation of DFS.
Diosady knew the key was to keep iron and iodine from coming into contact with each other, but he didn’t have a clear idea of how to do it. He and one of his lab technicians tried to create iodine microcapsules with a thin, water-resistant coating around each particle, to form a barrier between iodine and iron. They tried several encapsulation formulas, but found that in order to mix evenly with salt, the spray-dried microcapsules had to be crushed very finely. During a test in Ghana, consumers complained that the results were lumpy.
“At that point, we went back and said, okay, what can we do to make it bigger? We therefore began to seek to agglomerate these iodine particles to make them more or less correspond to the size of the salt, ”explains Diosady. “That was the goal: to make products that match the size of the grains of salt to avoid separation.”
In the early years of the project, the salt in most countries was neither as uniform nor as sparkling white as it is today, which worked to Diosady’s advantage. “The color wasn’t a big deal. Particle size was not a big deal. It was variable, ”he recalls. But as production became centralized, salt became more uniform in appearance and taste. “We were pursuing a moving goal: the quality of salt over the past 20 years has steadily improved,” says Diosady.
Unable to make the iodine capsules work the way they wanted, Diosady and his team decided to switch up the pantyhose and focus on encapsulating the iron instead. That way, everything they came up with could, in principle, be mixed with existing iodized salt.
This left the question of what type of iron to use. “We went to try a whole series of iron compounds,” says Diosady. Most resulted in an uncolored salt that would never fly with consumers. He remembers those failed attempts every year when winter hits Toronto. “I always use salt in my driveway which is yellow, green – all the different colors that these things have created,” he says.