Am I taking a risk of getting food poisoning by eating vegetables, such as tomatoes and spinach, raw?
Food poisoning. Wash them before eating - is essential --- otherwise, no risk.
Yes, there's a risk. Raw fruits and raw vegetables have many benefits, but there are some drawbacks, which is why human cultures eat cooked food. Raw plants have tough Cellulose fiber, so require more chewing to break into the cells so we can get the nutrients. Extra fiber is fermentation food for our gut bacteria, leading to gas. Without cooking, one eats live bacteria, viruses, fungi, and parasites that are on food.
Yes, so wash them. Uncooked or improperly cooked food, even organic foods, can carry infectious bacteria or viruses. Wash your fruits and vegetables well before eating. Wash melons, etc. Before cutting them open.