Once upon a time all we had to worry about was moist proteins, meats and such. Now with industrial agriculture the norm we also have to look out for fresh produce. Contamination is happening in the fields and factories so cases of food poisoning occur in fresh tomatoes, melons, spinach and lettuce to name a few. The only way to insure safety is to grow your own.
On the other hand, compared to the amount of food produced food borne illness is still quite rare. If you wash and trim your produce well and cook your meats to safe temperatures you will be fairly safe.