Listeriosis from food?

Dear Alice,

Can a person get listeriosis from eating processed food such as dry slim jim, sausage, etc.?

— Cautious

Dear Cautious,

Listeriosis is an infection caused by eating food contaminated with the bacterium, Listeria monocytogenes, found in soil and water. Vegetables can become contaminated from soil or manure used as fertilizer. This bacterium may be found in raw foods, such as uncooked meats, vegetables, and raw (unpasteurized) milk and dairy. Processed foods, such as soft cheeses, hot dogs, luncheon meats, cold cuts, fermented or dry sausage, and other deli-style meats and poultry may contain Listeria monocytogenes.

Listeria monocytogenes is killed during pasteurization and heating procedures during meat processing. However, if good manufacturing standards are not upheld, foods may become contaminated. The United States Department of Agriculture (USDA) has established steps for inspectors to follow to prevent food contamination by this pathogen.

Symptoms can appear anytime from a few days to several weeks, with an average time of three weeks for those exposed to become ill with listeriosis. The indicators are flu-like symptoms: fever, muscle aches, and sometimes nausea or diarrhea. If the infection spreads to the nervous system, headaches, stiff neck, confusion, loss of balance, or convulsions can occur. Listeriosis is especially dangerous for pregnant women. They may only experience mild flu-like symptoms, but the illness may be passed on to the infant. This can lead to miscarriage, stillbirth, or serious health problems for the child. There is a blood test that available to test or listeriosis; sometimes a spinal fluid or urine test may be done if a pregnant woman suspects she has been infected. It is especially important that pregnant women seek treatment right away if they are feeling any symptoms. Treatment for a listeria infection generally involves going to a hospital for intravenous antibiotics.

General recommendations to reduce one's risk of getting listeriosis include:

  • Thoroughly cooking raw beef, pork, and poultry
  • Washing vegetables thoroughly before cooking
  • Keeping uncooked meat separate from vegetables, cooked food, and ready-to-eat foods
  • Not drinking unpasteurized or raw milk and other products made from this source
  • Washing hands, utensils, and cutting surfaces thoroughly after handling uncooked foods

Persons at particular risk for listeriosis infection include pregnant women, newborns, the elderly, and individuals with weakened immune systems. For these people, the Centers for Disease Control and Prevention (CDC) also recommends:

  • (Re)heating hot dogs, luncheon meats, or deli meats until they are steaming hot
  • Washing hands thoroughly after handling hot dogs and deli meats to avoid cross-contamination of other foods with fluid from these items
  • Avoiding soft cheeses: feta, Brie, Camembert, blue-veined cheeses, and queso blanco fresco (Mexican style cheeses)
  • Avoiding pâtés or meat spreads. Canned or shelf-stable pâtés or meat spreads are safe.
  • Avoiding refrigerated smoked seafood unless it is part of a cooked dish that is heated until steaming hot. This type of fish is labeled "nova-style," "lox," "kippered," "smoked," or "jerky," and may be salmon, trout, whitefish, cod, tuna, or mackerel. This type of fish is found in the refrigerator section of the grocery store, or may be sold at delicatessens. Canned or shelf-stable smoked seafood may be eaten.

Do your part for safer snacking by practicing the recommendations listed above and seeking treatment for any symptoms you are experiencing.

Last updated Mar 23, 2015
Originally published Jan 31, 2003