Here is the context:
Culinary cultural fusion is all the rage; more novels translated from languages then ever before, although few are read, and in the surest sign of cultural globalization, football, the world's game, finally has reached America.
Actually I cannot get the grammar of the phrase. Why did the speaker use the preposition in with it? Wouldn't it make sense without it? If it would not, then could you please explain what the difference is with in and without?