Potatoes, maize and tomatoes reached Europe and Asia only after:

1. Many common foods were unknown to our ancestors five centuries ago. 2. They were introduced in Europe and Asia after Christopher Columbus reached the continent later called the Americas. 3. The crops themselves came from the American Indians. _Source: NCERT Class 10 Social Science, 'India and the Contemporary World II', Ch 3 'The Making of a Global World'_