A sick feeling washes over you:  nausea, stomach cramps, headache and fever.  Vomiting and diarrhea may soon follow.  The symptoms are familiar to anyone who’s had the flu, but there may be another culprit—food that’s gone bad.

Food-borne illness, or “food poisoning,” usually comes from eating food tainted with bacteria or their toxins.  Other types of microbes—like viruses or parasites—can also be behind food poisoning.  People have long known that raw meat, poultry and eggs can harbor disease-causing microbes.  But in recent years even fresh fruits and vegetables have caused headline-making outbreaks of food-borne illness.

Fortunately, most cases of food poisoning aren’t life threatening.  You usually recover after a few days of misery.  But children, the elderly and people with weakened immune systems are at more serious risk.

Food poisoning can cause debilitating abdominal pain, nausea, headache, fatigue, vomiting, diarrhea and dehydration.  Symptoms usually appear several hours to several days after eating tainted food, depending on the microbe.  For example, Salmonella bacteria—a common source of food-borne disease—usually cause illness 12 hours to 3 days after ingestion, with symptoms lasting about 4-7 days.

Noroviruses are another major cause of food-borne illness.  Found in the vomit or stool of infected people, noroviruses can live in food and on surfaces.  Careful hand-washing helps prevent the spread of these highly contagious viruses.

Some microbes are especially deadly.  Listeria monocytogenes—a bacterium found in some ready-to-eat and raw foods—has caused the majority of food-related deaths in the U.S. in recent years.  Listeria is unusual because it can grow and multiply even at refrigerator temperatures.

E. coli bacteria have been responsible for many highly publicized outbreaks of food-borne disease caused by contaminated vegetables or undercooked hamburgers.  The O157:H7 strain recently made headlines when it caused 53 people to be hospitalized in a four-state region.  They’d eaten tainted lettuce at a fast-food chain.  The O157:H7 strain is especially harmful to children because it can cause sudden kidney failure.

You can take an active role in fighting food poisoning.  Thorough washing and proper cooking eliminates many disease-causing microbes.  See the “Wise Choices” box for more tips on preventing food poisoning.

The most common way to treat food poisoning is to drink plenty of fluids.  The sickness usually subsides within a few days.  Contact your doctor, though, if you develop signs of severe dehydration, such as dry mouth, less urination or increased heart rate, or if you develop signs of shock, like weak or rapid pulse, clammy skin or chest pain.