Pregnant women, cancer patients and the elderly are among those who are at greatest risk of serious illness -- even death -- from eating food contaminated with a bacterium called listeria.

Listeriosis is a serious infection caused by eating food contaminated with the bacterium Listeria monocytogenes.

New concerns about this bacterium have surfaced, and as a result, the government has issued warnings about foods that pose the most dangerous for those who are most vulnerable.

Listeriosis can be avoid by following some simple tips:

• Ready-to-eat foods such as hot dogs, luncheon meats, sausages and other deli-style meats should be cooked until piping hot.
• Always wash hands with hot, soapy water after handling any of these foods. Be sure to wash cutting boards, dishes and utensils that have come into contact with these food products.
• Avoid unpasteurized milk and foods, such as unpasteurized cheese.
• All meats should be cooked thoroughly.
• Leftovers should be thoroughly reheated.

The symptoms of listeriosis include fever and muscle aches and gastrointestinal symptoms such as nausea and diarrhea. If the infection spreads to the nervous system, symptoms can include headache, stiff neck, confusion, loss of balance and convulsions.

Pregnant women are about 20 times more likely than other healthy adults to contract listeriosis. Experts said that hormonal changes during pregnancy leave the immune system less able to fight the infection.

Listeriosis during pregnancy can cause premature delivery, miscarriage, fetal death or illness in the newborn after birth.

Healthy adults and children occasionally get infected with Listeria, but they rarely become seriously ill. For people with weakened immune systems, following these recommendations could save their lives.

Additional Resources:

• FightBAC!
• USDA/FDA Foorborne Illness Information Center
• Information from the Centers for Disease Control and Prevention