Each year close to 50 million people in the U.S. become sick from contaminated food, according to the U.S. Centers for Disease Control and Prevention. Many just have mild stomach pain or feel queasy or nauseated and their symptoms go away in a day or two. But tens of thousands of people are hospitalized for the condition each year, usually for dehydration caused by diarrhea and vomiting brought on by the food poisoning.

Seniors should be especially cautious because as you age the risk of becoming very ill grows due to the fact that your immune system cannot always fight off the illness.

Food poisoning is your body reacting to food or water contaminated by bacteria or viruses or, less commonly, a parasite, during improper cooking, handling, or storage. By taking the proper precautions you can often avoid becoming sick, says Niket Sonpal, M.D., a gastroenterologist and professor at the Touro College of Osteopathic Medicine in New York City.

Common Culprits

Meat, poultry, eggs, and shellfish can harbor bacteria that make you sick if you eat them raw or undercooked, or if your hands or preparation surfaces are not cleaned after contact, says Sonpal. Dairy foods and food with mayonnaise need to be refrigerated within two hours, or within an hour if the outside temperature is 90 degrees or over, Sonpal adds.

Produce can harbor bacteria if handled with unwashed hands or irrigated with contaminated water. Recent recalls for contaminated fruits and vegetables include bagged salad, red onions, and peaches.

Always wash fruits and vegetables under cold running water. For recalls, pay attention to news reports and consider signing up for a loyalty card from the supermarket, which can generate an alert if there’s a recall, says Don Schaffner, Ph.D., a professor in the department of environmental and biological science at Rutgers University in New Brunswick, N.J.

When to Call the Doctor

In some cases, food poisoning can lead to serious health consequences. For example, dehydration from vomiting or diarrhea can reduce the blood volume in your body causing you go to into shock. Call the doctor if you have:

• Dehydration symptoms including dry mouth, little or no urination, dizziness, or sunken eyes
• Cannot hold down fluids without vomiting
• Diarrhea that lasts more than two days
• Severe vomiting or stomach pain
• Fever of 102 or higher
• Black, tarry, or bloody stool
• Muscle weakness
• Blurred vision
• Confusion
• Jaundice, which can be a sign of hepatitis A, which can be caused by contaminated foods such as seafood.

Basic Food Safety

Make sure you take these precautions with food to lower your risk of food poisoning:

Clean: Wash your hands and surfaces often when preparing food; wash utensils, cutting boards and counter tops with hot, soapy water. Rinse fresh fruits and vegetables under running water to wash off pesticides and dirt.

Separate: Safe prep includes using separate cutting boards for raw meat, poultry, seafood, and eggs. In your grocery bags and refrigerator secure meat, poultry, and seafood away from each other, so juices cannot run and contaminate other foods, says Sonpal.

Cook to the right temperature: Use a food thermometer and follow these temperatures:

• 145°F for whole cuts of beef, pork, veal, and lamb
• 160°F for ground meats, such as beef and pork
• 165°F for all poultry
• 165°F for leftovers and casseroles
• 145°F for fin fish or cook until flesh is opaque

Chill: Keep your refrigerator at 40°F or below and if the power goes out throw out food in the fridge after four hours. Also, thaw frozen food in the refrigerator, in cold water, or in the microwave.