Listeria is a gram-positive, rod-shaped bacterium that is an environmental pathogen and can grow under either anaerobic (without oxygen) or aerobic (with oxygen) conditions. Of the six species of Listeria, only Listeria monocytogenes causes disease in humans.
Those at risk of a Listeria infection (Listeriosis):
- Pregnant women: They are about 10-20 times more likely than other healthy adults to get listeriosis. About one-third of listeriosis cases happen during pregnancy. Fetuses are also highly susceptible to infection and severe complications.
- Newborns: Newborns can develop life-threatening disease from perinatal and neonatal infections
- Persons with weakened immune systems
- Persons with cancer, diabetes, kidney, or gastrointestinal disease
- Persons with HIV/AIDS: Individuals with HIV/AIDS are almost 300 times more likely to get listeriosis than people with healthy immune systems.
- Persons who take glucocorticosteroid medications (such as cortisone)
- Persons of advanced age: One risk assessment showed people over 60 years old were 2.6 times more likely to develop listeriosis than the general population. And in 2011, the median age of diagnosed cases in people who were not pregnant was 71 years old.
What foods are at risk of Listeria contamination:
- Foods at ready-to-eat salad bars, sandwich bars and delicatessens
- Ready-to-eat meats (deli meats)
- Pre-cut fruits and vegetables
- Soft and semi-soft cheeses
- Unwashed raw fruits and vegetables
- Soft-serve ice cream
- Raw shellfish and seafood
- Unpasteurized dairy products
- Cold cured or prepared meats
- Raw and cooked poultry
How to Avoid a Listeria Infection:
- Avoid the foods above if you are a person in an at risk category
- Keep your refrigerator at 41°F (5°C) or below to slow the growth of Listeria.
- Ready-to-eat foods, such as deli items and leftovers, should be stored no longer than seven days at or below 41°F
- Thoroughly cook raw food from animal sources, such as beef, pork, or poultry to a safe internal temperature.
- Avoid getting fluid from hot dog and lunch meat packages on other foods, utensils, and food preparation surfaces, and wash hands after handling hot dogs, luncheon meats, and deli meats.
- Rinse raw fruits and vegetables thoroughly under clean running tap water before eating.
- Keep uncooked meats, fish, and poultry separate from vegetables, and from cooked foods and ready-to-eat foods while shopping and in storage.
- Do not drink raw (unpasteurized) milk, and do not eat foods that have been made from or include unpasteurized milk.
- Eat cut melon within four hours or refrigerate it at or below 41°F for no more than seven days.
- Wash hands, knives, countertops, and cutting boards after handling and preparing uncooked foods.
- Consume perishable and ready-to-eat foods as soon as possible.