I have travelled to Cartagena and Barranquilla twice and Santa Marta twice. I have read that tourists should stay away from fruit, veggies, fish and so I have done this on my trips except I accidentally drank some freshly squeezed juice on my first trip and became sick. On my last trip I did not get sick but I was starved when I got home because I limited my food to grilled chicken, rice, steak, fries, and rice in restaurants.
I love Colombia and I am even thinking of retiring there, but I am afraid of eating some of the food.