Some food historians say that 1491 to 1493 are the years the world began in terms of food, that is. Prior to 1492, eight plants--corn, beans, squash, chile, tomato, potato, vanilla, and cacao--existed only in the Americans. Italy didn't have the tomato; Ireland didn't have the potato, nor Russia the vodka distilled from it; and there were no chiles in South Asia. When these ingredients crossed the ocean, they drastically transformed the way the Old...