"Racism is a product of having taken your serfs from a region in which people look different from you, which is an obvious foundation for basing an ideology upon.
I hereby suggest that any slave system in which the slaves looked appreciably different from the masters would result in a racist ideology."
The indentured servitude that affected a significant number of white settlers was not significantly better than outright slavery. Howard Zinn , in People's History of the U.S. also writes at length that racism was specifically developed by the ruling class in order to put an end to a developing fraternization between poor white settlers and black slaves.
So, the racist ideology you mention is exactly what did not develop spontaneously, but had to be nurtured and reinforced by the ruling class in order to avoid class-based uprisings.
Joanna