Photo: Mackenzie Stroh

Q: Some foods that are supposed to be good for you can be contaminated, like fish with mercury or spinach with E. coli. Should I eat these foods?
— N. Thomas, Brooklyn, New York

A: There's no way to sugarcoat it: One in four Americans suffers food poisoning every year, according to Centers for Disease Control and Prevention estimates. But the vast majority of these illnesses are minor and short-lived. The chance that you'll come to serious harm eating a healthy diet is slim.

The truly risky outbreaks that do occur—melamine in baby formula, E. coli on spinach leaves, salmonella in peanut butter—are horrifying but rare. And there isn't much consumers can do; we need closer monitoring of processing plants and more thorough testing of imported food.

But you can control how food is prepared at home, so check out the government's cleaning and cooking guidelines at www.FoodSafety.gov/ (click on Consumer Advice). Also, the following steps can help ensure that your diet stays safe:

• Eat fresh foods. The less processing involved, the less opportunity there is for bacteria to contaminate food.
  
  
• When possible, choose foods grown locally—within a couple of hundred miles of where you live—to minimize the number of people or machines handling your food. To find farms or farmers' markets near you, go to LocalHarvest.org .
  
  
• Don't let scares about contaminants prevent you from eating healthfully. Mercury may be a concern with some fish, but that's no reason to avoid all seafood. Wild salmon, sardines, Pacific sole, and most shellfish have almost no mercury. (The nonprofit Natural Resources Defense Council has a guide at nrdc.org/health/effects/mercury/guide.asp .)
  
  
• Pesticide levels tend to be high for certain types of produce, such as strawberries, peaches, nectarines, grapes, lettuce, and bell peppers. But washing your fruit and vegetables for 30 seconds can reduce your exposure. If you decide to go organic when buying these items, remember that you'll still need to wash them. (For more guidance, visit GreenerChoices.org .)

David L. Katz, MD, is director of the Yale-Griffin Prevention Research Center and president of the nonprofit Turn the Tide Foundation.