At a gleaming new factory in China’s central hinterland, masked workers in white uniforms season and sift through mounds of latiao, a popular snack that has found hungry fans overseas. Spicy, sweet and curiously chewy, Chinese latiao – literally “spicy strips” – are made by cooking wheat-flour dough under high pressure and heat. Despite their reputation as junk food, the snacks originally developed as emergency supplies have grown into an industry worth more than 60 billion yuan (US$8.9...