I think it's a natural animal instinct to be frightened and defensive against something you don't consider "part of your group", but I don't think that equates to inherent racism.
Sorry to sound all preachy, but I honestly don't think I am racist - there are aspects of certain people, certain cultures etc that I don't like, but I don't think it's the race of the person that determines that. I might not like Saudi Arabian laws, or American ethics, but that doesn't mean I in any way dislike, or am prejudiced against, Saudis or Americans. That's not to say I don't recognise that they may be a product of their culture.
I hope people aren't prejudiced against me on the basis of my ethnicity (although, being a white, straight, non-disabled north-west-european blond-hair-blue-eyed tall male, that really hasn't been a problem for my demographic in the past!!)