What happens to a food when people stop eating it? Most of the food we eat today comes from a handful of crops, but before we became a globalised society, our diet reflected a variety of plants, proteins and foods that were cultivated as local specialties. Now, as our diets become less diverse, these foods face a critical point in their existence. In this programme the BBC's Dan Saladino explores several stories of foods that are dying out and talks to the farmers and producers who are working to save them.

(Photo: Mexican Blue Corn Credit: Omar Torres/AFP/Getty Images)