Nairobi, Aug. 19 -- For Dennis Karema, the difference between running a business and building one that can matter at scale is impact.

"If I built a business that serves five people, yes, there is a little impact in that village. But what if I could build a business that serves 100 million farmers? Then that is actually part of transforming a continent."

It is an ambition that was sparked by watching his grandmother's tea leaves wither at a collection centre in Murang'a, eventually seeing him build a cold-chain business that now operates across 17 Kenyan counties and has begun crossing national borders.

SokoFresh, the company he co-founded in 2019 and where he is chief executive, has expanded into Seychelles and Madagascar, while also o...