Food to avoid when pregnancy includes those which are contaminated with the bacteria named Listeria. The bacteria poison the bloodstream which carries nutrients and vitamins to the baby via placenta. This in turn develops the condition named as listeriosis. What type of foods needs to avoid during pregnancy? Raw meat, eggs, undercooked meat, fish high in mercury, unpasteurized milk and cheese. All these may contain the bacteria. Also, shellfish is the food to avoid during pregnancy as it may contain vibrato bacteria. Cook it at 145 Fahrenheit so that bacteria get destroyed and you can have healthy food to eat.